Click on the map for a larger version (1280 x 898 pixels).

The Smithsonian Institution/United States Geological Survey Weekly Volcanic Activity Report for 2-8 December 2009 is available on the Global Volcanism Program website. The following is a summary and not a substitute for the full report.

• The current report: Weekly Volcanic Activity Report.
• Previous reports: Weekly Reports Archive.
• The SI/USGS map of volcanoes discussed this week.

New activity/unrest: Llaima (Chile).

Ongoing activity: Ambrym (Vanuatu), Chaitén (Chile), Colima (Mexico), Dukono (Indonesia), Fuego (Guatemala), Karymsky (Russia), Kilauea (Hawaii, USA), Kliuchevskoi (Russia), Rabaul (Papua New Guinea), Sakura-jima (Japan), San Cristóbal (Nicaragua), Shiveluch (Russia), Soufrière Hills (Montserrat), Suwanose-jima (Japan).

Note: a.s.l. = ‘above sea level’.

NEW ACTIVITY/UNREST

Llaima (Chile). Steam-and-gas plumes were observed rising from the main crater and E flank during 14 November-1 December. Although seismicity generally decreased, a new type of long-period, low-frequency earthquake was detected. An overflight on 4 December revealed fumarolic activity and some sulphur dioxide emissions coming mainly from fissures on the N crater wall and outer E and W flanks. The Alert Level was raised to Yellow, Level 3.

ONGOING ACTIVITY

Ambrym (Vanuatu). A diffuse plume from probably largely composed of sulphur dioxide was visible on satellite imagery acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) on 3 December.

Chaitén (Chile). Buenos Aires VAAC reported that emissions from the lava-dome complex drifted 15 km SE on 8 December.

Colima (Mexico). On 1 December a white plume rose 100 m above the crater and drifted E. On 2 December, incandescent tephra was ejected 50 m above the crater towards the SE. Later that day, a white plume rose 50 m and drifted SW.

Dukono (Indonesia). Darwin VAAC reported that during 5-6 December ash plumes from Dukono rose to 3 km a.s.l. and drifted 55-85 km NE and SE.

Fuego (Guatemala). Multiple explosions on 4 December produced ash plumes that rose to 4.2-4.7 km a.s.l. and drifted 15-18 km W. Ashfall was reported in communities downwind. Rumbling noises and incandescent block avalanches were also noted.

Karymsky (Russia). Seismic activity was above background levels during 27-30 November and 1 December. Data were not available during 2-4 December due to technical problems. Analyses of satellite imagery revealed a daily thermal anomaly and ash plumes that drifted 165 km E during 29-30 November and 1-2 December. The Level of Concern Color Code remained at Orange.

Kilauea (Hawaii, USA). During 2-8 December lava flowed SE from beneath the Thanksgiving Eve Breakout (TEB) and rootless shield complex through a lava tube system to reach the ocean at multiple locations between Waikupanaha and an area 700 m farther to the W. Thermal anomalies detected by satellite and visual observations revealed active lava flows on the coastal plain. Incandescence was occasionally seen from Pu’u ‘O’o crater; on 2 December, incandescence originated from vents on the E wall. The vent in Halema’uma’u crater continued to produce a white or off-white plume that drifted E, W, and SW, and dropped small amounts of ash downwind. Incandescence originated from multiple spattering holes in the deep floor of the vent cavity.

Kliuchevskoi (Russia). During 27 November-4 December seismic activity was above background levels and lava continued to flow down the ESE flank. Strombolian activity ejected tephra 300 m above the crater. Satellite imagery revealed a large daily thermal anomaly at the volcano. The Level of Concern Color Code remained at Orange.

Rabaul (Papua New Guinea). During 27 November-3 December dense white plumes and gray ash plumes rose from Tavurvur cone. Strong explosions produced ash plumes that rose 1.5 km above the summit and showered the flanks with lava fragments that were incandescent at night. Shock waves rattled windows in the Kokopo area, about 20 km SE. Incandescence from the summit crater was occasionally noted. During 2-4 December, ash fell in Rabaul town (3-5 km NW) and other villages downwind. Based on analyses of satellite imagery, the Darwin VAAC reported that during 5 and 7-8 December ash plumes rose to 2.4 km a.s.l. and drifted 45-55 km E.

Sakura-jima (Japan). Tokyo VAAC reported that explosions during 2-8 December produced plumes that rose to 1.5-2.7 km a.s.l. and drifted in multiple directions. On 4 and 8 December, pilots 30-65 km S of Kagoshima airport reported ash plumes that rose to an altitude of 1.8 km a.s.l. and drifted SW and NE.

San Cristóbal (Guatemala). Washington VAAC reported that on 6 December a gas-and-steam plume with possible ash drifted SW, and also noted smoke from local fires.

Shiveluch (Russia). During 27 November-4 December seismic activity was above background levels, possibly indicating that ash plumes rose to an altitude of 4.5 km a.s.l. Fumarolic activity was seen with a video camera. Analyses of satellite imagery revealed a large daily thermal anomaly from the lava dome and gas-and-steam plumes, possibly with ash, drifting 70 km E on 27, 28, and 30 November. The Level of Concern Color Code remained at Orange. Tokyo VAAC reported that on 4 December an eruption produced a plume that rose to an altitude of 5.8 km a.s.l.

Soufrière Hills (Montserrat). During 27 November-4 December activity from the lava dome continued at a high level. Pyroclastic flow activity was concentrated to the NE and W. The largest pyroclastic flows traveled NE down Tuitt’s Ghaut on 27 November and 2 December, reaching within 200 m of the sea. Associated ash plumes rose to altitudes of 4.6-6.1 km a.s.l. Pyroclastic flows also traveled W down Gages Valley, S down the White River valley and Gingoes Ghaut, and into the upper reaches of Tyers Ghaut (NW). One descended the Tar River valley to the E. Rockfalls cascaded directly from the summit of the lava dome into Tyers Ghaut. Ash venting from the S part of the lava dome was noted several times. Ashfall containing accretionary lapilli, reported from Salem, Old Towne, and parts of Olveston on the evening of 27 November, was associated with a pyroclastic flow down Tuitt’s and White Bottom Ghaut. The Hazard Level remained at 3.

Suwanose-jima (Japan). Tokyo VAAC reported an explosion from Suwanose-jima during 5-6 December. Details of possible resulting emissions were not reported.

ACKNOWLEDGEMENTS AND DISCLAIMER

The foregoing is a summary of the Smithsonian Institution/United States Geological Survey Weekly Volcanic Activity Report covering 2-8 December 2009. It is provided for information only, and is based on but not a substitute for the full report, which comes with its own criteria and disclaimers. The map base is derived from the Smithsonian Institution/USGS/US Naval Research Laboratory This Dynamic Planet website.

For all our coverage of the SI/USGS Weekly Volcanic Activity Reports: Weekly Volcanic Activity Reports « The Volcanism Blog.

In Chile the state emergencies office ONEMI has issued a new bulletin on the situation at Llaima volcano, which has been on Yellow Alert since 5 December, reporting observations made by OVDAS-SERNAGEOMIN.

Seismicity at Llaima remains unstable ‘with events associated with fluid movements and processes of degasification’, and that numerous fumaroles have been visible when the weather has permitted direct observation.

Low concentrations of sulphur dioxide measured on 5 and 6 December indicate that the main crater remains obstructed. An overflight on 4 December also confirmed the blockage of the crater; fumarolic activity from fissures, mainly of white steam with some blue sulphur dioxide emissions, was observed on the north-east flank of the volcano and the interior north and exterior east and west walls of the crater. The largest fissure, and the seat of the greatest activity, was that situated on the north-east flank of the volcano which was the location of gas and ash emissions during April and June 2009.

Based on these observations ONEMI warns that new eruptive activity cannot be ruled out. Yellow Alert applies to Llaima and the districts of Melipeuco, Vilcún, Curacautín, Cunco and Lonquimay, and the 4-kilometre radius exclusion zone around the volcano remains in force.

The bulletin also announces that from today monitoring of Llaima is to be strengthened with several new broadband seismological stations, and three SERNAGEOMIN fieldwork teams are to be despatched to the area.

For all our Llaima coverage: Llaima « The Volcanism Blog.

Information
Global Volcanism Program: Llaima – summary information for Llaima (1507-11=)
Oficina Nacional de Emergencia – Chilean government emergencies office
SERNAGEOMIN – Servicio Nacional de Geología y Minería, Chile
Proyecto Observación Visual Volcán Llaima – Llaima Visual Observation Project

Some more information on activity at Llaima volcano in Chile, which is currently on Yellow Alert.

Chilean state emergencies office ONEMI has issued a new bulletin, reporting that ‘a seismic swarm associated with internal degasification’ and marked by ‘increased release of the volcano’s internal energy’ was detected at Llaima between 16:00 and 18:00 local time on 6 December. Fumarolic activity has been continuing, and the main crater remains obstructed. ONEMI is maintaining Yellow Alert for Llaima and surrounding communities, and the 4-kilometre radius exclusion zone remains in force.

Above: Webcam image of Llaima volcano viewed from Cherquenco on 18 November 2009 (OVDAS-SERNAGEOMIN). [source]

The state geological service SERNAGEOMIN have also published a new Llaima bulletin on their web site today, which notes that fumarolic activity and volcanic gas emissions were observed during the period 14 November to 1 December when weather permitted, and contains the following information about recent changes in the volcano’s seismic activity:

Regarding the seismicity associated with Llaima volcano, it has been marked by the occurrence of a new type of LP [long period] event, of low frequency (less than 3.0 Hz), characterized by a spindle-shaped envelope with a higher amplitude (energy) than the other types of LP seismicity and a duration in some cases of up to 4 minutes. A continuing decline in the numbers of the other three types of LP earthquakes was observed, with an average 5 earthquakes per hour being registered, of which two to three correspond to this new type of event. The background tremor kept its characteristics of amplitude and spectral content.

The foregoing (the changes in the types of seismic events, which appear to be generated by different mechanisms) implies a greater complexity in the internal dynamics of the volcano. In addition, the main crater remains blocked, so the likelihood of a possible volcanic reactivation is greater than in previous months.

Yellow Alert, notes the bulletin, indicates that ‘eruptive activity may occur within weeks or months’.

For all our Llaima coverage: Llaima « The Volcanism Blog.

Information
Global Volcanism Program: Llaima – summary information for Llaima (1507-11=)
Oficina Nacional de Emergencia – Chilean government emergencies office
SERNAGEOMIN – Servicio Nacional de Geología y Minería, Chile
Proyecto Observación Visual Volcán Llaima – Llaima Visual Observation Project

The Chilean state emergencies office ONEMI (Oficina Nacional de Emergencia) has declared a Yellow Alert for Llaima volcano and surrounding communities. According to an ONEMI bulletin issued yesterday, monitoring of the volcano by SERNAGEOMIN’s Observatorio Vulcanológico de los Andes del Sur (OVDAS) between 14 November and 1 December showed ‘continuing emission of water vapour, volcanic gases and background tremor’. This marks an increase in activity since mid-November – the appearance of background tremor is particularly significant. The bulletin reports that ‘considering the continuing obstruction of the main crater, and the appearance of these new types of seismic events, [OVDAS] indicates that these background conditions increase the likelihood of a possible eruptive reactivation of Llaima volcano, within the next few weeks’.

The Yellow Alert applies to the communities of Melipeuco, Cunco, Vilcún, Curacautín and Lonquimay: the authorities in these municipalities, along with those of the Conguillío National Park (within which Llaima is situated) are required to update and apply their emergency contingency plans and co-ordinate theire response with the local bureau of ONEMI. An exclusion zone of 4 km radius, centred on Llaima’s main crater, is in operation around the volcano itself.

In a further bulletin ONEMI clarifies that the effects of the increased alert level at Llaima are restricted to the enforcement of the exclusion zone around the volcano and more intensive monitoring of its activity, and that ‘the new Alert status does not create new restrictions on the normal activities of the population’.

UPDATE. The increased alert level ‘is a minor issue’ says the Intendenta of Araucanía Region, imposed by SERNAGEOMIN in response to a change in seismic behaviour: ‘this measure is not to alarm the community  but is an alert to the [monitoring] teams to remain vigilant’.

For all our Llaima coverage: Llaima « The Volcanism Blog.

News
Declaran alerta amarilla por actividad del volcán en Chile – El Financiero, 5 December 2009
Chile decreta alerta amarilla en torno a volcán Llaima – El Comercio, 5 December 2009
Alerta en Chile por posible erupción del volcán Llaima – La Nación, 5 December 2009
Alerta amarilla por riesgo de erupción del volcán Llaima – Europa Press, 6 December 2009
Llaman a la calma ante aumento de actividad del volcán Llaima – 123 Chile, 6 December 2009

Information
Global Volcanism Program: Llaima – summary information for Llaima (1507-11=)
Oficina Nacional de Emergencia – Chilean government emergencies office
SERNAGEOMIN – Servicio Nacional de Geología y Minería, Chile
Proyecto Observación Visual Volcán Llaima – Llaima Visual Observation Project

While we wait for SERNAGEOMIN to get around to publishing the latest Chaitén bulletins (which eventually appear as PDFs at the OVDAS site), two brief reports have appeared on the press page of SERNAGEOMIN’s main site, dated 9 November and 16 November, the latter economically combined with a report on Llaima. Translations as follows.

SERNAGEOMIN bulletin on Chaitén volcano
9 November 2009 [original here]

Between 16 and 30 October the eruptive activity of Chaitén volcano, both visually and seismically, has shown no large changes, continuing the developments of the last period. The preceding indicates that the eruptive activity continues with the growth of the dome complex.

On the other hand, the quantity of pyroclastic material both from rock falls and emitted by the block-and-ash flows and lateral explosions has created large accumulations in the adjacent valleys and particularly the valley of the Chaitén river, so that the occurrence of lahars towards Chaitén during periods of intense rain cannot be ruled out.

In consequence, given that the seismicity remains at elevated levels – an effect of the growth of the dome complex – and that the eruptive activity continues with the possibility of the generation of block-and-ash flows in random directions, which may affect surrounding valleys with the generation of new lahars, SERNAGEOMIN suggests maintaining Volcanic Red Alert.

View from the DGAC camera in Chaitén on 30 October. In general, the base of the column appears much wider, although its height does not exceed 1.5 km above the domes.

SERNAGEOMIN bulletin on Chaitén and Llaima volcanoes
16 November 2009 [original here]

The images observed through the DGAC camera located in Chaitén to the south of the volcano show that during 31 October and 1 November the eruption has continued to produce one column, principally consisting of water vapour with occasional gas and ash. Because of the predominant winds in the area the height of the column has not exceeded 1000 metres above the dome complex. During the rest of the reporting period the continuing [cloud] cover has prevented any visual observation of the activity.

Images from the DGAC camera in Chaitén on 31 October (left) and 1 November (right).

Between 31 [October] and 1 November the seismicity has remained relatively stable compared with the preceding weeks indicating that the eruptive activity continues with the growth of the dome complex, only rarely observable recently because of the poor weather conditions in the area.

In consequence, given that the seismicity remains at elevated levels, an effect of the growth of the dome complex, and that the eruptive activity continues with the possibility of the generation of block-and-ash flows in random directions which may affect surrounding valleys with the generation of new lahars, SERNAGEOMIN suggests maintaining Volcanic Red Alert.

Llaima volcano

The poor meteorological conditions did not permitt visual observation of Llaima up to 10 November when it was possible to observe that the weak emissions of water vapour around the principal crater and on the east side of the volcano continue, probably due to the melting of snow deposited in these locations.

Although the seismic activity has shown a slight decline in the number of LP earthquakes, its general characteristics have shown the same behaviour as during the preceding period and apparently the principal crater remains obstructed. Given these conditions, it is not possible to rule out a reactivation of the volcano.

In consequence, SERNAGEOMIN maintains Alert Level Green 2 and continues with permanent monitoring of the volcano, and suggests keeping the 4 km radius of exclusion around the principal crater.

Additionally it is reiterated that this alert could change suddenly, depending on the activity observed/registered at the volcano, so that it is recommended that community preparations are maintained along with the revision and updating of emergency plans.

[End of SERNAGEOMIN bulletins.]

For all our Llaima coverage: Llaima « The Volcanism Blog.
For all our Chaitén coverage: Chaitén « The Volcanism Blog.

Information
Global Volcanism Program: Chaitén – summary information for Chaitén (1508-41)
Erupción del Volcán Chaitén – extensive coverage of the Chaitén eruption
Global Volcanism Program: Llaima – summary information for Llaima (1507-11=)
Proyecto Observación Visual Volcán Llaima – Llaima Visual Observation Project
SERNAGEOMIN – Servicio Nacional de Geología y Minería, Chile

The Chilean state geological service SERNAGEOMIN has published a joint bulletin covering activity at Llaima and Chaitén volcanoes. The Llaima report covers the period 22 August to 1 September, and the Chaitén report covers 20-31 August. Translation as follows.

SERNAGEOMIN bulletin on Chaitén and Llaima volcanoes
Monday 7 September 2009

Llaima volcano

Although the seismicity of Llaima volcano has remained stable during the period between 22 August and 1 September, with RSAM values within normal ranges, sudden changes cannot be ruled out, possibly associated with instability in the magma column, which can be inferred from the marked instability in behaviour shown by the volcano during recent months. As a result, there is the continuing latent possibility of a volcanic reactivation.

In consequence, SERNAGEOMIN maintains Alert Level Green II and suggests keeping an exclusion zone of 4 km radius around the principal crater. It should be noted that OVDAS personnel are constantly attentive to the development of the volcano’s activity. It is reiterated that this alert could change suddenly, therefore it is recommended that the community stay prepared for any changes in activity that may occur and for corresponding revision and updating of emergency plans.

Photographs taken by Victor Hazeldine on 01-09-2009.

Chaitén volcano

For its part, the eruptive activity of Chaitén in the period between 20 and 31 August continued with the growth of the dome complex, which was only occasionally observed because of the winter weather conditions.

The images recorded by the DGAC camera, located in Chaitén, to the south of the volcano, show that the eruption continues in unchanging form with a column of gas and ash climbing, occasionally, to 1.5 km above the dome complex. Also block-and-ash flows persist, indicating that this structure continues to grow, particularly towards the western sector of the caldera.

The quantity of deposited pyroclastic material both from volcanic rocks that have been emitted by the block-and-ash flows and from lateral explosions have created large accumulations in the adjacent valleys and especially the Chaitén river valley, so that the occurrence of lahars towards Chaitén [town] during intense rains cannot be ruled out.

In consequence, given that the seismicity remains at high levels – an effect of the growth of the dome complex – and that the eruptive activity persists with the possibility of the generation of block-and-ash flows in random directions, which may affect the surrounding valleys and generate new lahars, SERNAGEOMIN suggests maintaining Volcanic Red Alert.

[End of SERNAGEOMIN bulletin.]

For all our Llaima coverage: Llaima « The Volcanism Blog.
For all our Chaitén coverage: Chaitén « The Volcanism Blog.

Information
Global Volcanism Program: Chaitén – summary information for Chaitén (1508-41)
Erupción del Volcán Chaitén – extensive coverage of the Chaitén eruption
Global Volcanism Program: Llaima – summary information for Llaima (1507-11=)
Proyecto Observación Visual Volcán Llaima – Llaima Visual Observation Project
SERNAGEOMIN – Servicio Nacional de Geología y Minería, Chile

The picture of Llaima above was taken by Victor Hazeldine on 1 September 2009 and comes from our friends at POVI (Proyecto Observación Visual Volcán Llaima). The view is of the east flank of the volcano, and shows abundant steam rising from thermally active areas around the summit. (Image copyright Victor Hazeldine.)

The following information about Llaima’s recent activity also comes from POVI:

The last summit eruption, as part of the current cycle started in may 2007, lasted 72 hour starting from April 4. The 3 block lava flows reached a total length of 12,5 km.

On April 24 and June 1st sporadic phreatic emission and red glow was observed from a 300 m long lateral active fissure on the eastern upper flank. Until mid July a weak red glow was observed on the western crater rim. The 350 m wide inner crater remains filled with pyroclasts and lava emitted during the long lasting current eruption cycle.

The following graphic shows the time table (chronology) of the current eruption cycle. Half column means weak to moderate ash eruption and/or lava flow (VEI 1). Long column means moderate to strong explosive strombolian eruption (VEI 2 -3).

[Click on the image above to see a larger version.]

Thanks, as ever, to all the team at POVI for keeping us up-to-date with developments at Llaima. For our report of the latest SERNAGEOMIN bulletin on Llaima, click here.

For all our Llaima coverage: Llaima « The Volcanism Blog.

Information
Global Volcanism Program: Llaima – summary information for Llaima (1507-11=)
Oficina Nacional de Emergencia – Chilean government emergencies office
SERNAGEOMIN – Servicio Nacional de Geología y Minería, Chile
Proyecto Observación Visual Volcán Llaima – Llaima Visual Observation Project

The Chilean state geological service SERNAGEOMIN has published brief updates on Chaitén and Llaima volcanoes on its website in a combined bulletin dated 31 August 2009. Translation as follows.

SERNAGEOMIN bulletin on Chaitén and Llaima volcanoes

Chaitén Volcano

In the period between 4 and 20 August the eruptive activity of Chaitén has continued with the growth of the dome complex – particularly towards the western sector of the caldera – observable only occasionally because of the winter season. The column of gases, composed of water vapour and ash, has occasionally risen to 1.5 km above the complex.

Moreover, the quantity of pyroclastic material from fallen volcanic rock originating from both block-and-ash flows and lateral explosions has formed important accumulations in the adjacent valleys and especially towards the valley of the Chaitén river, from which the fresh occurrence of lahars towards Chaitén during torrential rains cannot be ruled out.

In consequence, given that the seismic activity remains elevated as a result of the growth of the dome complex, with the possibility of the generation of block-and-ash flows which may affect the surrounding valleys including the new generation of new lahars, SERNAGEOMIN maintains Volcanic Red Alert.

Llaima Volcano

While seismicity at Llaima volcano tended to decrease in the early days of August, it has subsequently increased, slightly exceeding its usual values in this latest period (17-21 August). These oscillations in seismic activity (LP-type earthquakes [Long Period earthquakes] of high and low frequency) could be related to the rising and falling of the magma column located in the principal conduit of the volcano, demonstrating the instability of the magma column.

The absence of other types of seismic activity in this type of phenomenon suggests the existence of an unobstructed volcanic conduit, in which magmatic fluids can suddenly rise freely, bringing about a new eruptive phase.

Due to the markedly erratic behaviour which the volcano has shown during recent times, it is not possible to rule out its reactivation. Because of the foregoing, SERNAGEOMIN continues with Green Alert level 2, maintaining a 4-km radius of exclusion around the principal crater.

For all our Chaitén coverage: Chaitén « The Volcanism Blog.
For all our Llaima coverage: Llaima « The Volcanism Blog.

Information
Global Volcanism Program: Chaitén – summary information for Chaitén (1508-41)
Erupción del Volcán Chaitén – extensive coverage of the Chaitén eruption
Global Volcanism Program: Llaima – summary information for Llaima (1507-11=)
Proyecto Observación Visual Volcán Llaima – Llaima Visual Observation Project
SERNAGEOMIN – Servicio Nacional de Geología y Minería, Chile

Above: Water vapour emanations produced by atmospheric condensation at Llaima’s summit on 7 July, from the lava flow that descended the western flank in the April eruption and hot areas of the upper part of the eastern flank (image: SERNAGEOMIN).

The most recent SERNAGEOMIN bulletin on Llaima (7 July 2009 – click here for PDF) reports a continuing decline in the volcano’s activity since the most recent eruptive period between April and June this year. Steam has been visible around the summit and from areas where lava flows descended the flanks in April (visible in the picture above), caused by atmospheric condensation rather than by volcanic activity. SERNAGEOMIN also reports a decline in seismicity, with the number and energy of long-period earthquakes falling since June.

Above: Graph of seismic energy released between 6 June and 7 July, measured by the LAVE seismic station at Llaima. The high points on the right were produced by windy weather (SERNAGEOMIN).

Given the low levels of activity at Llaima over the last few weeks, SERNAGEOMIN has lowered the alert level from Yellow (Amarillo) to Green Level 2 (Verde Nivel 2), but warns that the danger of a reactivation of eruptive activity remains. A 4 kilometre radius exclusion zone has been imposed around the Llaima’s summit and SERNAGEOMIN are monitoring the volcano on a permanent basis.

The Chilean state emergencies office ONEMI have also issued a bulletin announcing that although the Yellow Alert has been lifted restrictions affecting access to the Conguillio National Park remain in place, and that recreational facilities within the park near Llaima’s summit will remain closed.

For all our Llaima coverage: Llaima « The Volcanism Blog.

News
Autoridades levantan alerta amarilla en el volcán Llaima – La Tercera, 10 July 2009
Autoridades levantaron alerta amarilla para el volcán Llaima – Radio Cooperativa, 10 July 2009

Information
Global Volcanism Program: Llaima – summary information for Llaima (1507-11=)
Oficina Nacional de Emergencia – Chilean government emergencies office
SERNAGEOMIN – Servicio Nacional de Geología y Minería, Chile
Proyecto Observación Visual Volcán Llaima – Llaima Visual Observation Project

The Smithsonian Institution/United States Geological Survey Weekly Volcanic Activity Report covering 3-9 June 2009 is available on the Global Volcanism Program website. The following is a summary and not a substitute for the full report.

• The current report: Weekly Volcanic Activity Report.
• Previous reports: Weekly Reports Archive.
• The SI/USGS map of volcanoes discussed this week.

New activity: Galeras (Colombia), Karangetang (Indonesia), Sangeang Api (Indonesia), Slamet (Indonesia).

Ongoing activity: Batu Tara (Indonesia), Chaitén (Chile), Dukono (Indonesia), Fuego (Guatemala), Karymsky (Russia), Kelut (Indonesia), Kilauea (USA), Llaima (Chile), Manam (Papua New Guinea), Pacaya (Guatemala), Popocatépetl (Mexico), Rabaul (Papua New Guinea), Redoubt (USA), Sakura-jima (Japan), Santa María (Guatemala), Shiveluch (Russia), Tungurahua (Ecuador), Ubinas (Peru).

NEW ACTIVITY

Galeras (Colombia). The volcano erupted on 7 June, producing a NW-drifting ash plume to 6.8 km a.s.l. and ashfall downwind. The eruption was preceded by a magnitude 4 earthquake ~3 km SSE of the crater at a depth of 2 km. On 8 June there was a magnitude 3.9 earthquake 1 km E at a depth of ~2 km, followed by two explosions about 5 minutes apart, audible up to 45 km distant. The first explosion produced an ash plume reported to have reached 10 km a.s.l. and drifted NW, the second and larger a plume that reached 13.7 km a.s.l. and drifted SE.

Karangetang (Indonesia). Over 1-6 June lava flows travelled 50 m E and 600 m SE, with incandescent rocks reaching as far as 2 km distant. On 1 June ‘white-to-grey-to-brownish’ plumes reached 700 m above the main crater and incandescent lava was ejected 500-700 m on 1 June. Tremor amplitude and earthquake numbers decreased on 4 June, and white plumes rose 50-300 m above the main crater 4-6 June.

Sangeang Api (Indonesia). An increase in earthquake activity caused the alert level to be raised on 4 June. Over 1 May to 3 June white plumes rose 5-25 m.

Slamet (Indonesia). There was an overall decrease in Slamet’s activity over 26 May to 4 June, with earthquake numbers and water temperatures around the volcano lower. White plumes rose 100-750 m. Inflation and an increased number of earthquakes were registered 5-7 June, white plumes with ash emissions rose 200-800 m above the crater, and incandescent material was ejected 50-200 m.

ONGOING ACTIVITY

Batu Tara (Indonesia). Ash plumes reportedly rose to 2.4 km a.s.l. and drifted 40-75 km NW, W and SW over 3-8 June. On 9 June an ash plume drifted 140 km W.

Chaitén (Chile). The lava dome complex continued to grow, with gas-and-ash plumes rising 1.5 km above the dome over 27 May to 8 June. Collapses of unstable slopes generated block-and-ash flows. During 5-9 June ash plumes reportedly rose to 1.5-3.7 km a.s.l. and drifted WSW, SE, ENE and NE, and a thermal anomaly was seen on satellite imagery on 7 June.

Dukono (Indonesia). Ash plumes were reported drifting 20-75 km NW and NE during 6-8 June.

Fuego (Guatemala). Explosions, some accompanied by rumbles and shock waves, produced ash plumes that rose to 4.1-4.7 km a.s.l. and drifted 10 km W, SW and S on 5, 8 and 9 June. Avalanches were reported and fumarolic plumes rose 150 m, drifting S and SW.

Karymsky (Russia). An explosion on 6 June was reported to have produced an ash plume to 3.4 km a.s.l.

Kelut (Indonesia). Occasional diffuse white plumes reportedly rose 50-150 m above the crater. The alert level was lowered on 9 June.

Kilauea (USA). Lava continued to flow SE to the Waikupanaha ocean entry, and the Kupapa’u ocean entry was active again from 4 or 5 June. Active surface flows were detected. The Halema’uma’u crater vent continued to produce a mainly white plume that drifted mainly SW. A molten lava pool produced bright incandescence, and lava was clearly visible on webcam views. SO2 emissions remained elevated.

Llaima (Chile). A small active lava outcrop produced incandescence in an area SW of the main crater during 5-8 June, and a small point on the E flank fissure produced incandescence on 6 June. Gas and steam emissions took place from an area W of the main crater.

Manam (Papua New Guinea). An ash plume was reported to have risen to 2.4 km a.s.l. and drifted ~40 km NW on 8 June.

Pacaya (Guatemala). Fumarolic plumes from McKenney cone rose 50-200 m and drifted W and SW. On the lower S flank 2-4 lava flows 150-300 m long were emitted.

Popocatépetl (Mexico). DUring 3-9 June steam and gas emissions were reported, with the plumes containing slight amounts of ash during 8-9 June.

Rabaul (Papua New Guinea). Tavurvur cone produced white and occasionally blue plumes to 1 km above the crater during 29 May to 6 June, and incandescence was visible at night. An ash plume drifted NW and caused ashfall on Rabaul town and surrounding areas on 5 June.

Redoubt (USA). The lava dome continued to grow, and by 9 June the dome extended 950 m down the N flank. During 3-9 June seismicity was low but above background, and small discrete earthquakes and rockfalls were detected in the summit region.

Sakura-jima (Japan). On 7 June an eruption produced a plume to 3 km a.s.l., and on 9 June an eruption produced a plume to 2.4 km a.s.l. that drifted N.

Santa María (Guatemala). Explosions from the Santiaguito lava dome complex on 5, 8 and 9 June produced plumes to 2.8-3.3 km a.s.l. that drifted SW. Gas plumes, sometimes grey, rose 300-600 m above Caliente dome. Avalanches took place on the S and W flanks.

Shiveluch (Russia). Seismic activity was above background levels 29 May to 5 June, and diffuse ash plumes were emitted, a plume on 1 June possibly rising to 3.8 km a.s.l. Steam-and-gas emissions and a daily thermal anomaly over the lava dome were observed. A possible eruption was reported on 7 June, producing a plume to 3.4 km a.s.l.

Tungurahua (Ecuador). Tremor and explosions were detected 3-9 June, a gas-and-ash plume rose to 200m and drifted W and lahars descended multiple drainage channels on 3 June. Ashfall was reported to the SW and W on 4 June, blocks descended the flanks and roars/cannonades were heard on 7-8 June.

Ubinas (Peru). Plumes rose to 6.1-6.7 km a.s.l., and possibly to 7.9 km a.s.l., on 5 June, and drifted to points S and W. On 6 and 9 June plumes rose to 6.1-7.6 km a.s.l. and drifted S and NE respectively.

ACKNOWLEDGEMENTS AND DISCLAIMER

The foregoing is a summary of the Smithsonian Institution/United States Geological Survey Weekly Volcanic Activity Report covering 3-9 June 2009. It is provided for information only, and is based on but not a substitute for the full report, which comes with its own criteria and disclaimers. The map base is derived from the Smithsonian Institution/USGS/US Naval Research Laboratory This Dynamic Planet website.

For all our coverage of the SI/USGS Weekly Volcanic Activity Reports: Weekly Volcanic Activity Reports « The Volcanism Blog.

From POVI (Proyecto Observación Visual Volcán Llaima) in Chile comes the following information and pictures of Llaima’s current activity.

The current cycle of strombolian activity at Llaima, which began in May 2007, is continuing. On 26 May 2009, after a period of unusually heavy rain, a 500-metre long fissure on the upper east flank of the volcano began to emit dense clouds of water vapour. On the following day, 27 May, small amounts of ash were observed mixed in with the water vapour, and on 28 May the vigour of the emissions and the ash content increased. The photograph below of the east flank, taken by Victor Hazeldine, shows the fissure and its emissions on 28 May.

Fissure on the upper east flank of Llaima volcano, with weak ash and water vapour emissions towards the north. (Image copyright Victor Hazeldine.)

On 1 June, after further bad weather, the energy of the intermittent emissions along the fissure increased. A powerful phreatic eruption began at 11:20 (local time) on 1 June. The eruption ceased by 12:00, and during that afternoon only one small subsequent eruption was observed.

Phreatic eruption at Llaima, 1 June 2009. Image captured at 11:23 local time (Image copyright POVI.)

In the early mornings the POVI surveillance camera at Melipeuco shows small, weak glowing points on the volcano, one on the western inner crater, and another sporadic point in the upper segment of the radial fissure. Since the phreatic fissure eruptions began seismicity has remained at normal levels (as measured by POVI instruments 20 km from the volcano) but the number and energy of LP (long period) earthquakes has increased.

Close-up view of phreatic activity at the radial fissure on the upper eastern flank of Llaima. Picture taken on 1 June 2009. (Image copyright Victor Hazeldine.)

The picture above, taken by Victor Hazeldine on 1 June, shows a rare close-up view of the phreatic activity at the fissure. The photograph was taken from a position south-south-east of the volcano, 12 km distant, and clearly shows the 500 m radial fissure on the upper east flank. During the night a small lava flow, divided into two parts, was visible at the top of the fissure.

[Many thanks to Werner Keller of POVI for providing this information and the above images exclusively to The Volcanism Blog. For copious and detailed coverage of Llaima, visit the POVI Llaima website.]

For all our Llaima coverage: Llaima « The Volcanism Blog.

Information
Global Volcanism Program: Llaima – summary information for Llaima (1507-11=)
Oficina Nacional de Emergencia – Chilean government emergencies office
SERNAGEOMIN – Servicio Nacional de Geología y Minería, Chile
Proyecto Observación Visual Volcán Llaima – Llaima Visual Observation Project

The Smithsonian Institution/United States Geological Survey Weekly Volcanic Activity Report covering 20-26 May 2009 is available on the Global Volcanism Program website. The following is a summary and not a substitute for the full report.

• The current report: Weekly Volcanic Activity Report.
• Previous reports: Weekly Reports Archive.
• The SI/USGS map of volcanoes discussed this week.

New activity: Karangetang (Indonesia), Reventador (Ecuador), Slamet (Indonesia)

Ongoing activity: Barren Island (India), Batu Tara (Indonesia), Chaitén (Chile), Colima (Mexico), Dukono (Indonesia), Ebeko (Russia), Fuego (Guatemala), Kilauea (Hawaii, USA), Llaima (Chile), Rabaul (Papua New Guinea), Redoubt (Alaska, USA), Sakura-jima (Japan), Shiveluch (Russia), Soufrière Hills (Montserrat), Suwanose-jima (Japan), Tungurahua (Ecuador), Ubinas (Peru), Veniaminof (Alaska, USA).

NEW ACTIVITY

Karangetang (Indonesia). 24 May, ash plume reported to 3.7 km a.s.l., drifted 75 km S.

Reventador (Ecuador). 26 May, diffuse ash plume to 6.4 km a.s.l. drifted SW, intermittent thermal anomalies, gas plumes with possible ash also observed.

Slamet (Indonesia.: Seismicity continued to rise or remain elevated with activity peaking on 17 May, white-to-brown plume to 800 m above crater, inflation detected, ashfall 5-9 km away. Lava fountains rose 100-400 m above crater rim during 12 and 21-23 May, white-to-grey emissions to 150 m above crater, incandescent material ejected onto W flank. 22 May, ashfall reported 5 km distant; 23 May, ash plume to 1 km above crater, ashfall on N flank; 24 May, ash plume to 700 m above crater.

ONGOING ACTIVITY

Barren Island (India). 20 May, ash plume to 2.1 km a.s.l., drifted 75 Km NE.

Batu Tara (Indonesia). 20 May, ash plumes to 3 km a.s.l., drifted 65 km NW; 26 May, ash plume to 2.4 km a.s.l., drifted 55 km NW; thermal anomaly noted on satellite imagery.

Chaitén (Chile). Lava dome complex continuing to erupt, gas-and-ash plumes to 1.5 km above the complex and collapses generated block-and-ash flows. Lava dome growth was concentrated in the SW area of the complex. 21 and 26 May, ash plumes to 2.4-3.7 km a.s.l., drifted SSE on 21 May and 45-50 km NE on 26 May.

Colima (Mexico). 21-25 May, white and grey plumes to 3.9-4.2 km a.s.l., drifted E, SE and S.

Dukono (Indonesia). 26 May, ash plume to 3 km a.s.l., drifted 90 km N.

Ebeko (Russia). 22 May, ash plume to 2.4 km a.s.l., drifted SE.

Fuego (Guatemala). 21 May, lahars descended to the W and SW; 25-26 May, explosions produced ash plumes to 4.1-4.7 km a.s.l., drifted W, SW, S and SE, with rumbles; 25 May, fumarolic plumes rose to 4.2 km a.s.l. and drifted S and SE; 26 May, ashfall reported to W and WSW.

Kilauea (Hawaii, USA). 20-26 May, lava flowed SE through lava tubes to the Waikupanaha and Kupapa’u ocean entries; the Halema’uma’u vent continued to produce a mainly white plume to 200-300 m which drifted N, NE and SW, and a molten lava pool produced varying incandescence.

Llaima (Chile). 12-18 May, sporadic incandescence and steam plumes reported in the SW of the main crater.

Rabaul (Papua New Guinea). During 14-20 May white/blue plumes from Tavurvur cone rose to 1 km above the crater, and summit incandescence was seen at night; 20-21 May ash plumes rose to 2.4 km a.s.l. and drifted 30-40 km SE and SW.

Redoubt (Alaska, USA). 20-36 May, seismicity remained above background levels and lava dome growth continued, with visible steam-and-gas emissions and occasional rockfalls producing minor ash clouds.

Sakura-jima (Japan). 26 May, eruption produced a plume to 2.7 km a.s.l., drifted NW.

Shiveluch (Russia). 15-22 May, seismicity above background levels; hot avalanche on 16 May produced an ash plume to 4.5 km a.s.l.; active fumaroles reported 17-18 May; possible ash plume rose to 5.3 km a.s.l. on 21 May; daily thermal anomaly detected over lava dome.

Soufrière Hills (Montserrat). 15-22 May, slight increase in activity, but remained overall at a low level; tectonic earthquakes at less than 3 km beneath the lava dome noted on several days, multiple lahars occurred on 18 May, two possible explosions detected on 21 May.

Suwanose-jima (Japan). 25 May, ash plume to 1.5 km a.s.l.

Tungurahua (Ecuador). 22, 24, 25 and 26 May, ash plumes rose 1-2 km above summit and drifted W, occasional roaring sounds and explosions reported, ashfall reported to the W and SW 20-23 and 25-26 May, crater incandescence seen 24-26 May.

Ubinas (Peru). 20 May, ash plume rose to 7.3 km a.s.l., drifted NE; two explosions reported on 25 May.

Veniaminof (Alaska, USA). Decline in seismicity up to 26 May.

ACKNOWLEDGEMENTS AND DISCLAIMER

The foregoing is a summary of the Smithsonian Institution/United States Geological Survey Weekly Volcanic Activity Report covering 20-26 May 2009. It is provided for information only, and is based on but not a substitute for the full report, which comes with its own criteria and disclaimers. for the full report, which comes with its own criteria and disclaimers. The map base is derived from the Smithsonian Institution/USGS/US Naval Research Laboratory This Dynamic Planet website.

For all our coverage of the SI/USGS Weekly Volcanic Activity Reports: Weekly Volcanic Activity Reports « The Volcanism Blog.

The Smithsonian Institution/United States Geological Survey Weekly Volcanic Activity Report covering 6-12 May 2009 is available on the Global Volcanism Program website. The following is a summary and not a substitute for the full report.

• The current report: Weekly Volcanic Activity Report.
• Previous reports: Weekly Reports Archive.
• The SI/USGS map of volcanoes discussed this week.

New activity: Galeras (Colombia), Nyiragongo (Dem. Rep. of Congo), Rinjani (Lombok Island, Indonesia), Veniaminof (Alaska, USA).

Ongoing activity: Arenal (Costa Rica), Batu Tara (Komba Island, Indonesia), Chaitén (Chile), Dukono (Halmahera, Indonesia), Ebeko (Paramushir Island, Russia), Kilauea (Hawaii, USA), Llaima (Chile), Nevado del Huila (Colombia), Rabaul (Papua New Guinea), Redoubt (Alaska, USA), Sakura-jima (Japan), Shiveluch (Kamchatka, Russia), Suwanose-jima (Japan), Tungurahua (Ecuador).

NEW ACTIVITY

Galeras (Colombia). Gas-and-ash plumes rose to 5.8 km and drifted NE on 6 May. A 90-100 m diameter vent in the main crater was observed producing incandescence during an overflight, and white plumes originated from multiple points inside and outside the crater. There was little volcanic tremor. On 9 May there was a magnitude 2.2 volcano-tectonic earthquake 6 km to the NE of the main crater at a depth of 10 km; seismicity (consisting of hybrid earthquakes and tremor) increased on 11 May, and hybrid earthquakes and tremor were detected. On 12 May steam plumes rose 250 m and drifted NW. The increase in seismicity, with other factors, is interpreted by INGEOMINAS as indicating a possible eruption in the offing, and the alert level for Galeras was raised on 11 May.

Nyiragongo (Dem. Rep. of Congo). Incandescence from Nyiragongo, ‘volcanic dust’ in the air and increased temperatures around the volcano have been reported by news outlets and the Goma Volcano Observatory.

Rinjani (Lombok Island, Indonesia). Seismicity continued to be elevated over 3-7 May, with tremor present, and on 4 May there was an ash eruption from Barujari cone producing a white-to-brown plume that rose 500-700 m and drifted N. Thick white ’smoke’ was seen on 7 May.

Veniaminof (Alaska). Seismic activity at Veniaminof increased over 6-7 May, with low magnitude earthquakes occurring at rates of 5-10 per hour during quieter periods and 1-3 per minute during periods of more intense activity. Seismicity remained elevated over 8-12 May. The summit caldera cone was seen to be steaming in its usual manner.

ONGOING ACTIVITY

Arenal (Costa Rica). Activity during April originated mainly from Crater C: gas emissions, sporadic Strombolian
eruptions, avalanches descending S, SW, and N flanks, small amounts of ejected pyroclastic material and acid rain affecting NE and SE flanks. Crater D showed only fumarolic activity.

Batu Tara (Komba Island, Indonesia). On 5 May an ash plume rose to 2.4 km a.s.l. and drifted 55 km W.

Chaitén (Chile). The dome complex continued to grow and produced 2 km gas-and-ash plumes and collapse-generated block-and-ash flows during 29 April-4 May. The large central spine was found during an overflight on 1 May to have fractured into three main blocks, and the surface of the lava dome complex was very irregular with several spines that had grown to heights of 100 m. During 5 and 10-12 May, ash plumes rose to 2.1-4.6 km a.s.l. and drifted N, NE, and ENE.

Dukono (Halmahera, Indonesia). Ash plumes from rose to 3-3.7 km a.s.l. and drifted 20-110 km SE over 5-7 May.

Ebeko (Paramushir Island, Russia). Activity continued with gas-and-steam plumes containing small amounts of ash observed on 2 May. Ash plumes rose to 2.1-2.4 km a.s.l. and drifted SW and SE over 9-11 May.

Kilauea (Hawaii, USA). Lava continued to flow through the lava tube system to the ocean entries at Waikupanaha (where there were explosions on 10 May) and Kupapa’u (where a bench collapse was detected through seismic signals on 6 May). A small active surface flow was observed. The Halema’uma’u crater vent continued to produce a white plume
that that drifted W and SW, and the brightest incandescence seen since early December 2008 was produced by a molten lava pool deep below the floor of the crater. Sulphur dioxide emissions were elevated, at 1100 tonnes/day (8 May) and 700 tonnes/day (10 May). The 2003-2007 average rate was 140 tonnes/day

Llaima (Chile). Sporadic incandescence was reported from an area in the SW part of the main crater over 28 April to 11 May, corresponding to a small outcrop of lava which produced occasional blocks which rolled down the W flank. Tephra was ejected from an area on the E flank which showed incandescence during the night and an almost continuous orange-brown plume rose 200 m during 5-11 May.

Nevado del Huila (Colombia). Extrusion of juvenile material was detected at the lava dome during overflights on 7 and 9 May.

Rabaul (Papua New Guinea). Ash plumes from Tavurvur cone rose to 3 km a.s.l. and drifted about 35 km E on 9 May.

Redoubt (Alaska, USA). Lava dome growth continues at Redoubt. Seismicity was elevated over 6-12 May and occasional rockfalls and steam-and-gas emissions (possibly with some ash) were observed. Seismicity intensified during 5-6 May, with nearly continuous small earthquakes near the summit, and steam emissions were vigorous, with minor ash content. Tremor nearly doubled in intensity on 6 May and the number of events increased; an ash emission produced a plume that rose to 3.7 km a.s.l. Over 6-7 May seismicity declined but continuous small earthquakes continued at the summit area. On 12 May seismicity decreased to low levels compared to other phases of
the eruption.

Sakura-jima (Japan). Plumes on 9 May rose to 2.1-3 km a.s.l. and drifted S, and on 12 May an ash plume drifted E at 1.8 km a.s.l.

Shiveluch (Kamchatka, Russia). Over 1-8 May seismic activity was above background levels, plumes probably rose to 6.7 km a.s.l., and a daily thermal anomaly at the lava dome was detected.

Suwanose-jima (Japan). Explosions were reported over 7-9 and 12 May.

Tungurahua (Ecuador). Ashfall occurred in Baños, about 8 km N, on 6 May. Steam plumes rose to below 6.5 km a.s.l. and drifted W over 6-8 May. The volcano was very noisy over 9-11 May, with cannonades and roaring sounds being reported. An ash plume rose to 6 km a.s.l. on 9 May, and ash plumes rose to 8 km a.s.l. on 10 May.

ACKNOWLEDGEMENTS AND DISCLAIMER

The foregoing is a summary of the Smithsonian Institution/United States Geological Survey Weekly Volcanic Activity Report covering 6-12 May 2009. It is provided for information only, and is based on but not a substitute for the full report, which comes with its own criteria and disclaimers. The map base is derived from the Smithsonian Institution/USGS/US Naval Research Laboratory This Dynamic Planet website.

For all our coverage of the SI/USGS Weekly Volcanic Activity Reports: Weekly Volcanic Activity Reports « The Volcanism Blog.

The Chilean state geological service SERNAGEOMIN have issued a bulletin reporting activity at Llaima volcano from 28 April to 4 May 2009. A shortened version has been published on the SERNAGEOMIN website (in company with a bulletin on Chaitén), and the full document (PDF) is available from OVDAS.

The bulletin reports the continuing sporadic presence of incandescent points in the south-western margin of the principal crater ‘corresponding with outcrops of lava from which, occasionally, blocks fall and roll down the slopes of the western flank of the volcano’. Weak steam emissions have been seen in the mornings from Llaima’s summit, produced by the condensation of cold air in contact with the heated areas of the volcano. There have been no significant changes in the seismic behaviour of the volcano, which is characterized by weak tremor and LP-type (long period) earthquakes of up to 70 seconds’ duration, ‘related to the continuing movement of fluids and gases in the interior of the volcano’. The number of LP earthquakes ranges between 15 and 18 per hour, which represents no significant change from previous weeks. Seismic energy released (RSAM) has shown a slight tendency to increase.

The bulletin concludes that ‘the situation of the volcano is still critical because of its erratic seismic behaviour, the obstruction of its crater, the sporadic emission of lava in the western margin of the principal crater and the occasional emissions of gas and particulate material from the summit and various points on the western flank.’ There could be renewed explosive activity and lava flows, and thus SERNAGEOMIN maintains Yellow Alert.

For all our Llaima coverage: Llaima « The Volcanism Blog.

Information
Global Volcanism Program: Llaima – summary information for Llaima (1507-11=)
Oficina Nacional de Emergencia – Chilean government emergencies office
SERNAGEOMIN – Servicio Nacional de Geología y Minería, Chile
Proyecto Observación Visual Volcán Llaima – Llaima Visual Observation Project

The Smithsonian Institution/United States Geological Survey Weekly Volcanic Activity Report covering 22 April 2009 to 28 April 2009 is available on the Global Volcanism Program website. The following is a summary and not a substitute for the full report.

• The current report: Weekly Volcanic Activity Report.
• Previous reports: Weekly Reports Archive.
• The SI/USGS map of volcanoes discussed this week.

New activity: Bagana (Papua New Guinea), Ebeko (Paramushir Island, Russia), Galeras (Colombia), Pagan (Mariana Islands), Reventador (Ecuador), Shiveluch (Kamchatka, Russia), Slamet (Java, Indonesia).

Ongoing activity: Barren Island (Andaman Islands), Batu Tara (Komba Island, Indonesia), Chaitén (Chile), Dukono (Halmahera, Indonesia), Fuego (Guatemala), Karymsky (Kamchatka, Russia), Kerinci (Sumatra, Indonesia), Kilauea (Hawaii, USA), Koryaksky (Kamchatka, Russia), Krakatau (Indonesia), Llaima (Chile), Pacaya (Guatemala), Rabaul (Papua New Guinea), Redoubt (Alaska, USA), Sakura-jima (Japan), Santa María (Guatemala), Soufrière Hills (Montserrat), Suwanose-jima (Japan), Tungurahua (Ecuador).

NEW ACTIVITY

Bagana (Papua New Guinea). An ash plume from Bagana was reported on 26 April, rising to 2.4 km a.s.l. and drifting 28 km south.

Ebeko (Paramushir Island, Russia). Continuing activity was observed over the period 17-24 April, with gas-and-steam plumes with some ash content rising to 2 km a.s.l. and drifting north-east during 17-19 April. Light ash fall occurred in Severo-Kurilsk (7 km to the east) on 22 April, and on 25-26 April ash plumes rose to 1.2-2.1 km a.s.l. and drifted south, south-west and west.

Galeras (Colombia). Two explosive eruptions occurred on 24 April: the first produced a shock wave detected up to 25 km away, and incandescent blocks were ejected causing firest on the north flank. About 30 minutes later a second eruption took place, less energetic than the first but longer lasting. Incandescence from both eruptions was visible from Pasto, 10 km to the east. An ash plume rose to 10.3 km a.s.l., and ashfall was reported in areas to the west, up to 20 km distant. On 25 April ash-and-gas plumes rose 1 km above the crater.

Pagan (Mariana Islands). Continuous steam emissions were reported from the north crater during 21-22 April, and a diffuse plume drifting 15 km west was detected on 23 April. Steam emissions had decreased on 28 April.

Reventador (Ecuador). An earthquake swarm was detected at Reventador on 26 March, followed by a decrease in seismicity to low levels. Seismicity increased on 23 April, with long-period events interspersed with bands of spasmodic and harmonic tremor, and steam plumes with low ash content rose to 5.6-6.6 km a.s.l. and drifted west. Satellite imagery revealed a thermal anomaly and a steam plume drifting 26 km west-south-west.

Shiveluch (Kamchatka, Russia). Seismic activity was elevated over 17-24 April, ash plumes probably rose to 4.5-5.3 km a.s.l., and satellite imagery revealed a daily thermal anomaly
on the lava dome. Fumaroles were reported to be active during 16-22 April, and a hot avalanche produced an ash plume to 4 km a.s.l. on 22 April. [More recent activity at Shiveluch is not covered by this SI/USGS report.]

Slamet (Java, Indonesia). During 19-23 April seismicity increased, diffuse white plumes rose about 50 m above the crater on 20 April, white and white-to-brownish plumes rose 50-800 m above the crater during 21-23 April. Press stories quoted a volcanologist’s report of lava being ejected up to 600 m and bursts of ash occurring up to 112 times over a 6-hour period.

ONGOING ACTIVITY

Barren Island (Andaman Islands). Ash plumes reported to 2.4 km a.s.l. and drifting 45-65 km north-east, east and south-east during 23-25 April.

Batu Tara (Komba Island, Indonesia). Ash plumes reported to 3 km a.s.l. and drifting up to 110 km in ‘multiple directions’ during 24-25 and 28 April.

Chaitén (Chile). During 15-21 April gas-and-ash plumes rose 1.5 km from the lava dome complex and seismicity remained elevated, with earthquakes up to magnitude 4.5 recorded. Ash plumes to 2.1-3 km a.s.l. and drifting north-east and north were reported on 25 and 28 April.

Dukono (Halmahera, Indonesia). Ash plume to 4.5 km a.s.l., drifting 150 km east, reported on 28 April.

Fuego (Guatemala). Explosions on 24 and 28 April produced ash plumes to 4.1-4.8 km a.s.l. that drifted 10 km south-west; rumbling noises and shock waves from some explosions were detected 5 km away; avalanches of blocks descended the flanks; and fumarolic plumes rose 50-150 m and drifted south, north-west and north. On 28 April, incandescent material was ejected 75-100 m into the air.

Karymsky (Kamchatka, Russia). Fumarolic activity was observed over 17-24 April, and a thermal anomaly on the volcano was detected on 17 April.

Kerinci (Sumatra, Indonesia). Increased seismicity was detected at Kerinci in early April, accompanied by light and dark plumes rising up to 500-600 m above the crater during 1-20 April. Ashfall occurred at a nearby observation post on 19 April, and ‘noises indicative of an eruption’ were heard at same location on 19-20 April.

Kilauea (Hawaii, USA). During 22-28 April lava continued to flow south-east through a lava tube system to the Waikupanaha (where occasional explosions occurred) and Kupapa’u (where a littoral cone is being built up) ocean entries. Surface flows were present on the coastal plain. The Halema’uma’u crater vent continued to produce a white plume with occasional brown tinges that drifted south-west, north and north-east, and incandescence was intermittently observed.

Koryaksky (Kamchatka, Russia). Seismic activity was reported to be above background levels and weak volcanic tremor was present over 17-25 April. Gas plumes with small quantities of ash drifted in multiple directions over 17-18 April; satellite imagery on the same dates detected gas-and-ash plumes that drifted 100 km north-east. A sulphur dioxide plume was detected extending about 15 km from the volcano. Seismic activity decreased to background levels, with occasional tremor, over 25-28 April.

Krakatau (Indonesia). Local residents reported increases in activity and some evacuated themselves, but the volcanological authorities said nothing unusual was going on. Loud blasts, lava flows and ash plumes rising to 200-800 m above Anak Krakatau crater were reported.

Llaima (Chile). On 24 April ash plumes were observed at an area on the east flank about 700 m below the crater for a period of about 1.5 hours. The presence of steam indicated sub-glacial activity.

Pacaya (Guatemala). On 24 and 28 April, gas emissions from MacKenney cone and occasional ash explosions ejecting tephra 15-25 m were observed, and the seismic network detected tremor and explosions. Rumbling sounds were audible 3-5 km away. Lava flows descended the south-west flank for 50-400 m and fumarolic plumes drifted south.

Rabaul (Papua New Guinea). Tavurvur cone produced white and grey plumes to 0.5-1.5 km above the crater which drifted east and south-east during 18-25 April. Incandescence was visible at night and occasional roaring noises were heard. Ashfall was reported about 20 km south-east and in surrounding areas. Ash plumes were reported to have risen to 3 km a.s.l. and drifted 55 km south and 35 km south-west on 27 and 28 April.

Redoubt (Alaska, USA). The lava dome at Redoubt continues to grow, with seismicity remaining at background levels over 22-28 April. Steam-and-gas plumes occasionally with small amounts of ash were observed on 22 April, and sulphurous odours were reported by pilots to the north-east on 22 and to the south on 28 April.

Sakura-jima (Japan). Things seem to be quietening down, with no large eruptions since 11 April, no deformation reported and low seismicity. The alert level was lowered from 3 to 2 on 24 April.

Santa María (Guatemala). The number of explosions from the Santiaguito lava dome complex has reportedly decreased over the last few weeks. During 24-28 April explosions at Santiaguito produced ash plumes drifting 5-8 km west-south-west, and gas plumes rose 25-75 m above Caliente dome.

Soufrière Hills (Montserrat). Over 17-24 April activity from the lava dome was at a low level. A small pyroclastic flow descended eastwards along the Tar River valley on 24 April.

Suwanose-jima (Japan). An ash plume was reported on 22 April, and an eruption on 23 April reportedly produced ash plumes to 1.2-1.5 km a.s.l. and drifted east and south, and an explosion was reported on 27 Apri. Explosions on 28 April produced plumes to 1.5-1.8 km a.s.l. which drifted east.

Tungurahua (Ecuador). Steam-and-gas plumes with occasional ash content rose to 6.5 km a.s.l. and drifted south-west and west during 22-28 April. Ashfall occurred to the south-west on 21 April, incandescence was seen from the crater over 21-22 April, incandescent blocks were ejected on 22 April. A lahar descended the Patacocha drainage on 25 April.

ACKNOWLEDGEMENTS AND DISCLAIMER

The foregoing is a summary of the Smithsonian Institution/United States Geological Survey Weekly Volcanic Activity Report covering 22 April to 28 April 2009. It is provided for information only, and is based on but not a substitute for the full report, which comes with its own criteria and disclaimers. The map base is derived from the Smithsonian Institution/USGS/US Naval Research Laboratory This Dynamic Planet website.

For all our coverage of the SI/USGS Weekly Volcanic Activity Reports: Weekly Volcanic Activity Reports « The Volcanism Blog.

SERNAGEOMIN have published a short update on activity at Llaima, dated 24 April 2009, on their website. Translation as follows.

24.04.2009 SERNAGEOMIN report on Llaima volcano

From 07:35 today, 24 April, an emission centre located on the eastern flank some 700m below the summit commenced an emission of gases which formed a column 500m in height and an associated plume which dispersed towards the east in accordance with prevailing wind conditions.

This activity continued until approximately 09:00. The emission of water vapour that accompanied the eruption of ash shows that the emission centre is located beneath the eastern glacier.

The area coincides with the sector which produced some explosions on the eastern flank during the first three months of 2008.

[Caption reads: Clearly visible is the emission of ash at 07:35 at about 700m below the summit on the eastern flank, which was much diminished by 10:00 (image POVI Werner Keller).]

There was no seismic precursory activity, seismicity remaining to date (24 April at 10:30) at a usual level, characterized by LP-type earthquakes [long period], reaching up to 20 earthquakes per hour.

In the same way, the RSAM seismic energy remains stable, with values varying between 16 and 25 units over the last 24 hours.

SERNAGEOMIN continues with permanent seismic and visual monitoring of the volcano, also evaluating the developing [eruptive] processes, and maintains Yellow Alert.

[End of SERNAGEOMIN bulletin.]

For all our Llaima coverage: Llaima « The Volcanism Blog.

Information
Global Volcanism Program: Llaima – summary information for Llaima (1507-11=)
Oficina Nacional de Emergencia – Chilean government emergencies office
SERNAGEOMIN – Servicio Nacional de Geología y Minería, Chile
Proyecto Observación Visual Volcán Llaima – Llaima Visual Observation Project

A lot has been going on around the world, volcanically speaking, over the past few weeks, and the NASA Earth Observatory has been featuring some wonderful satellite imagery of current volcanic events.

Submarine eruption in the Tonga Islands (acquired 26 March 2009): an ASTER image from NASA’s Terra satellite showing new land created by the eruption at Hunga Ha’apai, sediment-laden water around the island, and evidence of the destruction of vegetation by the volcanic action.

Plume from Mount Redoubt (acquired 26 March 2009): a series of images captured by the Geostationary Operational Environmental Satellite (GOES) of the plume produced by Mount Redoubt between 09:00 and 11:30 local time on 26 March 2009.

Plume from Rabaul Volcano (acquired 3 April 2009): a MODIS image from NASA’s Aqua satellite shows an off-white plume (suggesting mainly water vapour content) from Rabaul blowing away to the south-east.

Sulfur dioxide plume from Isla Fernandina (aquired 14 April 2009): the Ozone Monitoring Instrument (OMI) on NASA’s Aura satellite captured data on the SO2 plume emitted by the eruption of Fernandina in the Galapagos Islands.

Plume from Mount Pagan (acquired 15 April 2009): a MODIS image from NASA’s Terra satellite shows a gas-and-steam plume released by an eruption of Mount Pagan in the Mariana Islands.

Eruption from Llaima volcano, Chile (acquired 16 April 2009): the Advanced Land Imager (ALI) on NASA’s Earth Observing-1 satellite captured a stunning unobstructed view of Llaima’s barren, lava-layered summit area.

The NASA Earth Observatory is currently celebrating its 10th anniversary, and is inviting everyone to vote on their favourite Images of the Day from the last ten years of wonderful satellite imagery. Seven of the fifty finalists are volcano-related, and any one of them would be a worthy winner.

A combined update for Chaitén and Llaima volcanoes, dated 17 April 2009, is available on the SERNAGEOMIN website. Translation as follows.

17.04.2009 Sernageomin Bulletin on Chaitén and Llaima volcanoes

Since 15 April, when the energy released by the seismicity of Chaitén volcano reached 130000 units RSAM, the values have begun to fall slightly, remaining during last Thursday [16 April 2009] at 100000 units, that is to say, continuing to be very elevated. Llaima, however, has not shown visual signs of significant activity.

Chaitén Volcano

Since 15 April, when the energy released by the seismicity of Chaitén volcano reached 130000 units RSAM, the values have begun to fall slightly, remaining during last Thursday [16 April 2009] at 100000 units, that is to say, continuing to be very elevated. The seismic activity has continued to be characterized by HB-type earthquakes of large magnitude, between 4.0 and 4.5, these occurring every two to three hours.

The high seismic energy release is associated with a greater rate of emission of lava and a much accelerated growth of the dome complex. Moreover, there remains a high probability that block and ash flows will be generated by gravitational collapses.

In consequence, SERNAGEOMIN continues monitoring the evolution of the eruption through the network of stations deployed in the area and maintains Red Alert.

Llaima Volcano

Since 15 April Llaima volcano has not shown visual signs of significant activity. Moreover, the seismicity associated since 12:00 on Wednesday [15 April 2009] has continued, with weak background tremor and LP-type earthquakes up to 20 events per hour. In addition, some 3 earthquakes per hour of greater magnitude (energy) stand out. Finally, the level of seismic energy remains at an average of approximately 20 units RSAM.

SERNAGEOMIN continues permanent monitoring of the volcano’s evolution, also observing the developing processes and maintaining Red Alert, although the possibility of lowering to Yellow Alert is being considered as a result of the diminished seismicity and the absence of significant visible processes of activity.

[End of SERNAGEOMIN update.]

The regional authority responsible for the area around Llaima, the Intendencia de la Araucanía, lifted the Red Alert that had applied to eight communities near the volcano late on Friday, reports El Mercurio. However, a Yellow Alert remains in place for five areas, which La Tercera names as Melipeuco, Vilcún, Curacautín, Cunco and Lonquimay.

For all our Chaitén coverage: Chaitén « The Volcanism Blog.

For all our Llaima coverage: Llaima « The Volcanism Blog.

Information
Global Volcanism Program: Chaitén – summary information for Chaitén (1508-41)
Erupción del Volcán Chaitén – extensive coverage of the Chaitén eruption
Global Volcanism Program: Llaima – summary information for Llaima (1507-11=)
Proyecto Observación Visual Volcán Llaima – Llaima Visual Observation Project
SERNAGEOMIN – Servicio Nacional de Geología y Minería, Chile

The Smithsonian Institution/United States Geological Survey Weekly Volcanic Activity Report covering 8 April 2009 to 14 April 2009 is available on the Global Volcanism Program website. The following is a summary and not a substitute for the full report.

• The current report: Weekly Volcanic Activity Report.
• Previous reports: Weekly Reports Archive.
• The SI/USGS map of volcanoes discussed this week.

New activity: Ebeko (Paramushir Island), Fernandina (Galapagos Islands, Ecuador), Kliuchevskoi (Kamchatka, Russia), Llaima (Chile), Miyake-jima (Japan), Redoubt (Alaska, USA), Sakura-jima (Japan).

Ongoing activity: Arenal (Costa Rica), Batu Tara (Komba Island, Indonesia), Chaitén (Chile), Colima (Mexico), Dukono (Halmahera, Indonesia), Karymsky (Kamchatka, Russia), Kilauea (Hawaii, USA), Koryaksky (Kamchatka, Russia), Rabaul (Papua New Guinea), Shiveluch (Kamchatka, Russia), Soufrière Hills (Montserrat), Suwanose-jima (Japan), Tungurahua (Ecuador).

NEW ACTIVITY

Ebeko (Paramushir Island): 3-10 Apr 09, gas-and-steam plumes with some ash content to 3.4 km a.s.l., drifted 8 km southerly; 5 Apr 09, light ashfall reported in Severo-Kurilsk (7 km E); 12 Apr 09, ash plume drifted 6 km SE at 1.5 km a.s.l.

Fernandina (Galapagos Islands, Ecuador): 10 Apr 09: eruption began between 2200 on 10 Apr 09 and 0030 on 11 Apr 09; an overflight by Galapagos National Park personnel indicated a fissure eruption from the SW flank of the volcano, about 500 m from the summit crater, fissure was 200 x 10 metres and ejected lava fountains 15 m high; gas-and-ash plume drifted SW; 11-14 Apr 09, gas plumes possibly with some ash drifted up to 370 km W, SW, S, and N; 14 Apr 09, large thermal anomaly and sulphur dioxide detected.

Kliuchevskoi (Kamchatka, Russia): 3-10 Apr 09, fumarolic activity observed; 5 & 6 Apr 09, thermal anomaly detected; 5-8 Apr 09, weak volcanic tremor detected; 9 Apr 09, possible eruption produced plume to 4.9 km a.s.l., drifted NE; 11 Apr 09, another possible eruption detected.

Llaima (Chile): 6 Apr 09, rapid decline in activity; 7 Apr 09, weak emissions of gas and ash observed, overflight reported main crater completely blocked by a large pyroclastic cone with four inactive craters, sulphur dioxide and hydrochloric gas emissions, two lava flows descended W flank and one descended NE flank, all causing lahars; 7-10 Apr 09, intermittent incandescence from lava flow at SW base of pyroclastic cone observed, incandescent blocks descended W; 8 Apr 09, gas plume drifted NE; 9-10 & 13-14 Apr 09, gas and steam plumes rose from pyroclastic cone; 14 Apr 09, fumarolic activity from pyroclastic cone observed.

Miyake-jima (Japan): 1 Apr 09, eruption produced ash plume to 600 m above the crater, drifted E.

Redoubt (Alaska, USA): 8-14 Apr 09, lava dome continued to grow, reported as circular in shape, 400 m in diameter, in same location as previous lava dome; continuous sulphur dioxide plume seen on satellite imagery; smaller steam plumes with possible ash content observed.

Sakura-jima (Japan): 8 Apr 09, eruption produced plume to 2.7 km a.s.l.; 9 Apr 09, Vulcanian explosion ejected bombs up to 1.3 km distance, plume rose to 4.8 km a.s.l., drifted SW, pyroclastic flow traveled 1 km E, heavy ashfall reported in Kagoshima City (~10 km W); 10 Apr 09, eruptions
produced plumes to 2.1-2.7 km a.s.l., drifted W and S.

ONGOING ACTIVITY

Arenal (Costa Rica): during Mar 09 gas emissions, sporadic strombolian eruptions and occasional avalanches down SW flanks from Crater C; acid rain and small amounts of ejected pyroclastic material affected NE and SE flanks.

Batu Tara (Komba Island, Indonesia): 11-12 & 14 Apr 09, ash plumes to 1.8-2.4 km a.s.l., drifted 35-90 km W and NW.

Chaitén (Chile): 30 Mar – 6 Apr 09, collapses from central spine continued, and new smaller spine grew on the southern area of Dome 1; 8 Apr 09, seismic activity gradually increased; 11-12 Apr 09, numbers and magnitudes of earthquakes reached highest levels; during 9-11 & 14 Apr 09, ash plumes rose to 1.5-2.4 km a.s.l., drifted NE, ENE, and ESE.

Colima (Mexico): 8-10 & 12-13 Apr 09, white and gray plumes to 3.9-5.2 km a.s.l., occasionally
drifted E, S, SW, and W.

Dukono (Halmahera, Indonesia): 12 Apr 09, ash plume to 3 km a.s.l., drifted 55 km NW.

Karymsky (Kamchatka, Russia): 2 & 3 Apr 09, seismicity above background levels; 4 Apr 09, seismicity at background levels; 5 Apr 09, weak thermal anomaly detected; 9 Apr 09, fumarolic activity observed.

Kilauea (Hawaii, USA): 8-14 Apr 09, lava flowed SE through lava tube system to Waikupanaha and Kupapa’u ocean entries, occasional explosions at the Waikupanaha entry, surface flows detected, incandescence intermittently seen from Halema’uma’u vent, which produced white plume occasionally tinged brown, drifted mainly SW.

Koryaksky (Kamchatka, Russia): 7 & 8 Apr 09, seismicity elevated, at background levels on the other days 3-10 Apr 09; 7 Apr 09, weak volcanic tremor detected; during reporting period gas plumes
containing a small amount of ash rose to 5.4 km a.s.l., drifted NE, NW, SE, and SW; 11 Apr 09, ashfall reported in Petropavlovsk-Kamchatsky (30 km S).

Rabaul (Papua New Guinea): 3-9 Apr 09, white and grey plumes from Tavurvur cone rose 1 km above the crater, drifted SE and NW; occasion incandescence seen at night, light ashfall reported in Kokopo, ~20 km SE; 11-12 Apr 09, ash plumes rose to 2.4 km a.s.l., drifted up to 75 km NW; 14 Apr 09, ash plumes to 3 km a.s.l., drifted W and up to 120 km NW.

Shiveluch (Kamchatka, Russia): 3-10 Apr 09, seismic activity above background levels; 3-5 and 8-9 Apr 09, ash plumes likely rose to 7.5 km a.s.l.; 3-7 & 9 Apr 09, fumaroles active; daily thermal anomaly detected on the lava dome.

Soufrière Hills (Montserrat): 3-10 Apr 09, activity at a low level; heavy rainfall during 8-9 Apr 09, caused multiple lahars.

Suwanose-jima (Japan): 8 & 10 Apr 09, explosions reported.

Tungurahua (Ecuador): 9 Apr 09, steam plume rose 300 m above crater, drifted SW; 10 Apr 09, light ashfall reported to the SW; 11 Apr 09, lahar traveled SW down Mapayacu drainage; 14 Apr 09, steam-and-gas plume with some ash content to 7.5 km a.s.l., drifted N.

ACKNOWLEDGEMENTS AND DISCLAIMER

The foregoing is a summary of the Smithsonian Institution/United States Geological Survey Weekly Volcanic Activity Report covering 8 April to 14 April 2009. It is provided for information only, and is based on but not a substitute for the full report, which comes with its own criteria and disclaimers. The map base is derived from the Smithsonian Institution/USGS/US Naval Research Laboratory This Dynamic Planet website.

For all our coverage of the SI/USGS Weekly Volcanic Activity Reports: Weekly Volcanic Activity Reports « The Volcanism Blog.

The following two pictures of Llaima volcano in Chile, taken on 11 April 2009, have been provided exclusively to The Volcanism Blog by Werner Keller of POVI, Proyecto Observación Visual Volcán Llaima. These images are copyright Prof. Marco Millar (e-mail: keltico@hotmail.com). The pictures show one of the two lava flows from the western flank of the volcano. The rough surface typical of ʻaʻa type lavas can be seen clearly in the lower image.

Many thanks to Werner Keller and Prof. Marco Millar for these images. More can be found at the POVI website.

Werner Keller reports that the front lobes of the lava flows extruded during Llaima’s eruption of 3-8 April were located from satellite images at 1891, 1921 and 1946 metres above sea level, and that the total extent of the lava flows was 12.5 kilometres.

For all our Llaima coverage: Llaima « The Volcanism Blog.

The Smithsonian Institution/United States Geological Survey Weekly Volcanic Activity Report covering 1 April 2009 to 7 April 2009 is available on the Global Volcanism Program website. The following is a summary and not a substitute for the full report.

• The current report: Weekly Volcanic Activity Report.
• Previous reports: Weekly Reports Archive.
• The SI/USGS map of volcanoes discussed this week.

New activity: Ebeko (Paramushir Island), Krakatau (Indonesia) Llaima (Chile), Nyamuragira (Democratic Republic of Congo), Nyiragongo (Democratic Republic of Congo), Pacaya (Guatemala), Redoubt (Alaska).

Ongoing Activity: Asama (Japan), Batu Tara (Komba Island, Indonesia), Galeras (Colombia), Karymsky (Kamchatka, Russia), Kilauea (Hawaii, USA), Koryaksky (Kamchatka, Russia), Popocatépetl (Mexico), Rabaul (Papua New Guinea), Sakura-jima (Japan), Shiveluch (Kamchatka, Russia), Soufrière Hills (Montserrat), Suwanose-jima (Japan), Tungurahua (Ecuador).

NEW ACTIVITY

Ebeko (Paramushir Island): 3 Apr 09, alert level raised to Yellow; ash-and-gas plumes to 3.2 km a.s.l., drifted ~20 km NW and E; 13, 29 & 31 Mar 2009, ashfall up to 0.2 cm thick reported in Severo-Kurilsk, 7 km E

Krakatau (Indonesia): 27-30 Mar & 1 Apr 09, ash plumes to 200-800 m above Anak Krakatau crater; 2 Apr 09, ash eruption reported, resulting ash plume drifted more than 60 km S.

Llaima (Chile): 2-3 Apr 09, increase in frequency and amplitude of seismicity evolving into continuous seismic tremor, steam plumes with small amounts of ash emitted; late on 3 Apr 09, incandescence from main crater, weak strombolian explosions from northern cone within the crater; 4 Apr 09, strombolian activity and rhythmic explosions in the main crater originated from two nested pyroclastic cones, incandescent tephra ejected 700 m above crater; ashfall in Conguillío National Park, lava flow 1 km long traveled W towards the Calbuco River; 5 & 6 Apr 09, dark grey ash plume drifted E, continuous explosions, heavy ashfall to the E, lahars and lava flows reported; 7 Apr 09, gas-and-ash plume to 1 km above summit, drifted NE.

Nyamuragira (Democratic Republic of Congo): 23-27 Jan 09, seismic swarm reported, with increased seismicity along the East African Rift since then; 22 & 24 Mar 09, intense fumarolic activity in the summit crater of Nyamuragira observed, concentrated in southern area.

Nyiragongo (Democratic Republic of Congo): seismic swarm reported from Nyiragongo and Nyamuragira in January and increased seismicity along the East African Rift since then; frequent gas plumes, contributed to acid rain; 22 Mar 09, tremor detected; 22 & 24 Mar 09, active fumaroles observed along a fissure connecting the Shaheru (S flank) and Nyiragongo craters, strong methane concentrations detected, lava lake level had dropped 20 m and temperature of some fissures had risen by 4 degrees C compared to 27 February; a small area of the lava lake was active, lava fountains seen.

Pacaya (Guatemala): constant explosive activity from McKenney cone in late March and early April, vigorous degassing, strombolian explosions ejecting material 25 m into the air, lava flows descended W and SW flanks up to 300m.

Redoubt (Alaska): 1-3 Apr 09, continuing emission of steam, gases and small amounts of ash; 1 & 2 Apr 09, plume containing some ash to 4.6-7.6 km a.s.l., extended about 65 km ENE; 4 Apr 09, explosion produced ash plume to 15.2 km a.s.l., drifted SE, lahar descended Drift River valley; 5-6 Apr 09, small earthquakes and intermittent tremor continued, plume of primarily steam and gas continuously emitted to 7.7 km a.s.l., drifted SE; 6 Apr 09, gas-and-steam plume to under 7.7 km a.s.l., drifted NE; 7 Apr 09, small steam-and-ash plume to 4.6-6.1 km a.s.l., drifted 16-24 km SE.

ONGOING ACTIVITY

Asama (Japan): 7 Apr 09, Alert Level lowered from 3 to 2 (on a scale of 1-5).

Batu Tara (Komba Island, Indonesia): 5-6 Apr 09, ash plumes to 2.4 km a.s.l., drifted 40-210 km W.

Galeras (Colombia): 3-7 Apr 09, gas plumes, sometimes with ash content, originating from different areas in the main crater, to under 6 km a.s.l., and zones of high temperatures noted.

Karymsky (Kamchatka, Russia): 27 Mar – 3 Apr 09, seismic activity above background levels; 31 Mar 09, thermal anomaly detected.

Kilauea (Hawaii, USA): 1-7 April, lava flowed SE through lava tube system to reach Waikupanaha and Kupapa’u ocean entries, surface flows detected, occasional explosions at Waikupanaha ocean entry; Halema’uma’u vent continued to produce mainly white plume drifting SW, incandescence intermittently seen from the vent

Koryaksky (Kamchatka, Russia): 27 Mar – 3 Apr 09, seismic activity at background levels, gas plumes with small amount of ash to 4 km a.s.l., drifted E, SE, S, and W; 27-28, & 31 Mar & 1-2 Apr 09, gas-and-ash plumes drifted 313 km E, in southerly directions.

Popocatépetl (Mexico): 1 Apr 09, ash plume rose 1 km above the summit; 2 Apr 09, small ash emission observed.

Rabaul (Papua New Guinea): 27 Mar – 2 Apr 09, white and occasionally grey (or brown) plumes from Tavurvur cone rose 1 km above the crater, drifted SE and NW; incandescence from summit crater seen at night; 2 Apr 09, light ashfall reported in Rabaul town (3-5 km NW) and surrounding areas; 5 apr 09, ash plume to 2.4 km a.s.l., drifted ~ 37 km NE; 7 Apr 09, ash plumes to 3 km a.s.l., drifted NW.

Sakura-jima (Japan): 5-7 Apr 09, explosions and eruptions produced plumes to 2.1-3.0 km a.s.l., drifted SE (5 Apr 09) and S (7 Apr 09).

Shiveluch (Kamchatka, Russia): 27 Mar – 3 Apr 09, seismicity above background, ash plumes likely rose to 5.5 km a.s.l., fumaroles active daily; 31 March 09, explosions produced ash plumes to 6 km a.s.l.; 1 Apr 09, daily thermal anomaly detected, ash plume drifted 80 km S.

Soufrière Hills (Montserrat): 27 Mar – 3 Apr 09, activity at a low level; 1 Apr 09, small pyroclastic flow traveled E down Tar River Valley; 6 Apr 09, ash plume drifting at 2.7-4.9 km a.s.l. reported.

Suwanose-jima (Japan): 6 Apr 09, explosions reported.

Tungurahua (Ecuador): 1-3 & 5 Apr 09, steam or steam-and-ash plumes rose to maximum 1 km above crater, drifted S, SW, and NNW; 6 Apr 09, fumarolic plumes to 500-600 m; light ashfall reported SW.

ACKNOWLEDGEMENTS AND DISCLAIMER

The foregoing is a summary of the Smithsonian Institution/United States Geological Survey Weekly Volcanic Activity Report covering 1 April to 7 April 2009. It is provided for information only, and is based on but not a substitute for the full report, which comes with its own criteria and disclaimers. The map base is derived from the Smithsonian Institution/USGS/US Naval Research Laboratory This Dynamic Planet website.

For all our coverage of the SI/USGS Weekly Volcanic Activity Reports: Weekly Volcanic Activity Reports « The Volcanism Blog.

The Chilean state geological service SERNAGEOMIN seems to have had some kind of technological crisis over the past 24 hours, with their main site intermittently inaccessible, and the Observatorio Volcanológico de los Andes del Sur (OVDAS) site still broken as of posting time. The latter site is so ugly and annoying that its total disappearance would be little cause for regret, except that it is where SERNAGEOMIN post PDFs of their volcanic activity bulletins, when they get around to it. The following bulletin on Llaima (8 April 2009) and a second short report (8 April 2009, 10:30) therefore come from the main SERNAGEOMIN site, which is currently back in the land of the living.

08.04.2009 SERNAGEOMIN Bulletin on Llaima Volcano

After 74 hours of a vigorous strombolian eruptive phase, accompanied by emissions of lava, on 6 April at 23:00 the eruption declined abruptly in intensity until it reached a very weak level with little ash emission, this phase ending on 7 April at 14:00.

The main crater has been blocked by a large pyroclastic cone, which surpasses in height the edge of the highest peak of the volcano.

Currently, the volcano is maintaining only gaseous emissions in the form of a weak fumarole. The seismic signal corresponds to earthquakes of LP [long period] type (up to 20 per hour) with an average of 30 units RSAM.

During 5 April most of the volcano has been permanently obscured. In the morning a lahar was reportedly generated towards the río Captrén which cut the road between Curacautín and the Conguillío National Park. In the afternoon it was possible to see part of the plume of ash, of dark grey colour, directed towards the east.

Throughout the following day, 6 April, there remained poor visibility conditions, although occasionally it was possible to see the cloud of gas and ash directed principally towards the east (Lago Verde). During the afternoon it was possible to confirm the cutting of the road in the Captrén area and possibly to hear periodic explosions associated with the fall of ash and fine lapilli towards the north-east.

The column was of much lighter colour (little ash concentration) indicating a diminution in the intensity of the eruption. During the night no incandescence or glow was seen.

In the morning of 7 April, meanwhile, only weak emissions of ash and volcanic gases were observed. On this day an overflight was carried out by an aircraft of Club Aéreo de Temuco, in the company of the Governor of Cautín, Mr Christian Dulansky. The principal observations made were as follows:

The main crater of the volcano is completely covered and obstructed by a large pyroclastic cone with four inactive craters, with only gaseous emissions of sulphur dioxide and hydrochloric acid.

On the west flank two main lava flows were observed, the southern flow with a length of some 4.5 kilometres, which had been completely encased in the glacier and blocks of ice upon it, which melted and evaporated, carrying dark brown-coloured water into the río Calbuco. The northern flow had a similar length, and was held up and divided into two arms of 1 kilometre, one towards the headwaters of the río Calbuco and the other towards the headwaters of the río Lanlan, with a lesser load of water entering the area of the shelters.

On the north-east flank another lava flow came from the base of the pyroclastic cone towards the headwaters of the río Captrén (Fig. 3), which generated lahars which descended this valley and cut the road between Curacautín and the Conguillío National Park (Fig. 4).

The glacier on the west flank of the volcano showed cracks and ridges of ice, suggesting creeping of the glacial mass. During the overflight of 4 April the glacier and its cracks were completely covered by the mantle of pyroclasts.

The headwaters of the río Calbuco showed a large burden of muddy water moving through various tributaries, however, it was possible clearly to see the saturation of most of it [with volcanic deposits], since at the road bridge (between Cherquenco and Melipeuco) the water flow was much lower. Remains of tree trunks along its path were evidence of the passing of the lahars that were reported on 4 April.

Seismic activity

The seismic activity which occurred on 5 and 6 April continued to register an energetic tremor, which seismic energy oscillated between 900 and 1600 units RSAM. Moreover, on 6 April at 20:33, a superficial VT-type [volcano tectonic] earthquake was recorded with a magnitude of 1.5, with an epicentre beneath Llaima volcano. Two and a half hours later, at 23:00 approximately, in a sudden way, the energetic tremor declined from 1100 to 19 RSAM units in just under two hours, a phenomenon common in this eruptive cyle which began in May 2007. Finally, during today, seismic activity has been characterized by up to 20 LP-type earthquakes per hour, of low amplitude, with an oscillation of RSAM values between 15 and 50 units.

As explained above, the status of Llaima volcano remains critical because of its erratic behaviour and the obstruction of its crater. If there is an eventual reactivation, the most critical areas are the valleys of the Calbuco, Lanlan and Captrén rivers, because of the possibility of the generation of lahars. Moreover, the generation of ashes, affecting principally the sector east of the volcano.

In consequence, SERNAGEOMIN maintains Red Alert while this post-eruptive situation continues.

[End of SERNAGEOMIN bulletin, 8 April 2009.]

08.04.2009 SERNAGEOMIN Bulletin on Llaima Volcano (10:30)

During the night it was possible from Melipeuco to see intermittent incandescence at the south-west foot of the large pyroclastic cone that completely fills the main crater. From this lava was emitted at a very low rate and incandescent blocks rolled down the slope of the volcano.

Today, 8 April, from dawn until the present hour a very weak fumarole of volcanic gases (SO2 and HCI) has been seen which emerges from various points on the summit of the pyroclastic cone and forms a thin fumarolic plume in a north-east direction because of the prevailing winds from the south-west.

Preliminary calculations have enabled the indication that the height of the large pyroclastic cone surpasses by 70 metres the summit of the principal crater, that is to say, Llaima volcano would have a current altitude of 3240 metres above sea level (originally 3169 meters above sea level).

In relation to the seismicity, this remains at very low levels characterized by the presence of LP-type earthquakes (up to 20 per hour), of little energy, with RSAM varying between 17 and 19 units during the last few hours.

SERNAGEOMIN continues with permanent visual and seismic monitoring from various points around the volcano, evaluating, in addition, the effects of the last eruptive phase, and maintaining Red Alert.

[End of SERNAGEOMIN bulletin, 8 April 2009, 10:30.]

For all our Llaima coverage: Llaima « The Volcanism Blog.

Information
Global Volcanism Program: Llaima – summary information for Llaima (1507-11=)
Oficina Nacional de Emergencia – Chilean government emergencies office
SERNAGEOMIN – Servicio Nacional de Geología y Minería, Chile
Proyecto Observación Visual Volcán Llaima – Llaima Visual Observation Project

The Smithsonian Institution/United States Geological Survey Weekly Volcanic Activity Report covering 27 May-2 June 2009 is available on the Global Volcanism Program website. The following is a summary and not a substitute for the full report.

• The current report: Weekly Volcanic Activity Report.
• Previous reports: Weekly Reports Archive.
• The SI/USGS map of volcanoes discussed this week.

New activity: Karangetang (Indonesia), Makian (Indonesia), Slamet (Indonesia).

Ongoing activity: Bagana (Papua New Guinea), Batu Tara (Indonesia), Chaitén (Chile), Dukono (Indonesia), Etna (Italy), Kilauea (Hawaii, USA), Llaima (Chile), Nevado del Huila (Colombia), Popocatépetl (Mexico), Rabaul (Papua New Guinea), Redoubt (Alaska, USA), Sakura-jima (Japan), Shiveluch (Russia), Soufrière Hills (Montserrat), Tungurahua (Ecuador), Ubinas (Peru).

NEW ACTIVITY

Karangetang (Indonesia). 30-31 May, seismicity increased and tremor was detected. Diffuse white plumes rose 10-50 m and crater incandescence was seen on 30 May, white emissions rose 100 m above Utama Crater on 31 May, incandescent material descended as far as 2.3 m, mostly down S flank.

Makian (Indonesia). Seismicity, particularly tremor, increased during 28 May-2 June.

Slamet (Indonesia). 27 May, ash plume rose to 4.3 km a.s.l., possible plume rose to 6.1 km.

ONGOING ACTIVITY

Bagana (Papua New Guinea). 2 June, ash plume to 2.4 km a.s.l., drifted 75 km W.

Batu Tara (Indonesia). 27 May-2 June, ash plumes to 2.4 km a.s.l., drifted 25-75 km NW, W and SW; thermal anomaly detected 29 May.

Chaitén (Chile). 20-27 May, gas-and-ash plumes rose 1.5 km from the growing lava dome complex and collapses caused by instable slopes generated block-and-ash flows. Seismicity remained elevated with large hybrid earthquakes at 5-9 km beneath the western part of the dome complex. 28-29 May and 1-2 June, ash plumes rose to 1.8-2.4 km a.s.l.

Dukono (Indonesia). 27-28 May, ash plumes to 3 km a.s.l., drifted 55-110 km NE.

Etna (Italy). 25-31 May, the NW-SE-trending fissure E of the summit craters continued to produce active lava flows, There was degassing from the Northeast Crater, the NW and SE Bocca Nuova vents, from the E flank of the Southeast Crater and at summit fumarolic fields.

Kilauea (Hawaii, USA). 27 May-2 June, lava continued to flow SE through lava tubes to the Waikupanaha ocean entry and (until 31 May) the Kupapa’u ocean entry. Active surface lava flows were also detected on 30 May. The Halema’uma’u crater vent continued to produce a mainly white plume with an occasional brown tinge, that drifted mainly SW. A molten lava pool near the base of the cavity produced varying incandescence.

Llaima (Chile). A 2-square-kilometre area of elevated temperatures was observed on the E flank during an overflight on 1 June. Small areas of gas emission, a small cone in formation about 800 m below the crater and a 300-metre-long E-W-trending fissure 200 m from the rim of the main crater, emitting brown ash and steam plumes, were also observed. There were weak fumaroles at the summit crater.

Nevado del Huila (Colombia). A seismic swarm took place on 28 May that included magnitude 4 and 4.8 earthquakes. On 31 May an episode of tremor occurred associated with an ash emission, and a further pulse of tremor was detected on 2 June.

Popocatépetl (Mexico). 27 May-2 June, emissions of steam and gas observed, with slight amounts of ash during 27-29 May.

Rabaul (Papua New Guinea). 21-28 May, white and occasionally blue plumes from Tavurvur cone rose 1 km above the crater and incandescence from the summit crater was observed at night.

Redoubt (Alaska, USA). Seismicity remained low but above background 27 May-2 June. Lava dome growth continued.

Sakura-jima (Japan). An explosion on 30 May produced a plume to 4.6 km a.s.l. that drifted SE. On 31 May an ash plume rose to 3 km a.s.l., and on 1 June eruptions produced plumes to 2.1-3.4 km a.s.l, some of which drifted S.

Shiveluch (Russia). Seismic activity was above background levels 22-29 May; steam-and-gas emissions were observed 21-23 May, and plumes with small amounts of ash rose to 4 km a.s.l. on 22 May. A daily thermal anomaly was detected over the lava dome.

Soufrière Hills (Montserrat). Activity during 22-29 May was at a low level: a possible small explosion followed by a rockfall occurred on 23 May, and a small pyroclastic flow descended 1 km E on 24 May, producing an ash plume that drifted W.

Tungurahua (Ecuador). Strombolian activity was observed at night during 26-28 May, followed by nocturnal incandescence at the crater until 1 June. On 27-29 and 31 May thermal anomalies were detected. There was the usual range of noises: explosions, cannonades and roars. Steam-and-ash plumes rose to 7 km a.s.l. and drifted W and SW on 28 May, and ashfall was reported 28-30 May.

Ubinas (Peru). On 29 and 31 May eruptions produced ash plumes to 5.5-6.7 km a.s.l. that drifted NE and SW. A bluish gas plume with some ash content was reported on 1 June, and gas-and-ash plumes rose 0.9-1.5 km a.s.l. and drifted SE following an explosion on 2 June.

ACKNOWLEDGEMENTS AND DISCLAIMER

The foregoing is a summary of the Smithsonian Institution/United States Geological Survey Weekly Volcanic Activity Report covering 27 May-2 June 2009. It is provided for information only, and is based on but not a substitute for the full report, which comes with its own criteria and disclaimers. for the full report, which comes with its own criteria and disclaimers. The map base is derived from the Smithsonian Institution/USGS/US Naval Research Laboratory This Dynamic Planet website.

For all our coverage of the SI/USGS Weekly Volcanic Activity Reports: Weekly Volcanic Activity Reports « The Volcanism Blog.