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Chaitén bulletins: no. 109 (30 October 2009) and no. 110 (13 November 2009) 24 November 2009

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In a remarkable development, SERNAGEOMIN has just released not one but two Chaitén bulletins to the public. Now available on the OVDAS ‘informes’ page are Chaitén bulletins 109 (PDF here, covering 16-30 October) and 110 (PDF here, covering 31 October to 13 November). Translations as follows.

CHAITÉN VOLCANO
TECHNICAL BULLETIN NO. 109
16-30 OCTOBER 2009
OVDAS-SERNAGEOMIN

1. Visual monitoring

During this period the volcano has remained obscured and only occasionally on 25 and 30 October has it been possible to observe the dome complex and its column of gas and ash. In general, the base of the column has appeared much wider, although the altitude has not exceeded 1.5 km above the domes (Fig. 1).

Chaiten 30 October 2009
Fig. 1. View from the DGAC camera in Chaitén on 30 October.

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Catching up with Chaitén (and Llaima) 20 November 2009

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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.

Chaiten 30 October 2009
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.

Chaiten 31 October 2009 (left), 1 November 2009 (right)
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 Volcanism Blog

Chaitén bulletin no. 108 (16 October 2009) 31 October 2009

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SERNAGEOMIN bulletin no. 108 on the Chaitén eruption, covering the period 1-15 October 2009, has been published and can be accessed (PDF) via the SEGEMAR website. A shortened version can be found on the SERNAGEOMIN website. Translation of the complete document as follows:

CHAITÉN VOLCANO
TECHNICAL BULLETIN NO. 108
1-15 OCTOBER 2009
OVDAS-SERNAGEOMIN

1. Visual monitoring

During most of the period covered by this bulletin, the volcano has remained covered by cloud. Occasonally images captured by the DGAC camera have allowed observation of columns of gases and ash emerging from the dome complex (Fig. 1, A).

SERNAGEOMIN-OVDAS personnel in the field confirm the growth of the domes and continual degasification with two important concentrations: one in the centre of the volcano, enriched with water vapour and ash) and the other towards the east of the volcano (predominantly water vapour); equally, numerous minor emissions are visible located on the volcanic edifice.

On the other hand, on 14 October at midday a vigorous explosion of the ‘piston type’ was generated: that is to say, a dense vertical projection of ash accompanied by a dispersion of particulate material forming a large cloud towards the west (Fig. 1; B to E).

Figure 1
Fig. 1. (A) Images from the DGAC camera, showing emissions of gases and ash. (B-E) Sequence of the ‘piston’ type explosion, occurring at midday on 14 October.

2. Seismic activity

In the process of increasing the monitoring network, currently in progress, a seismological station has been installed 1.5 km from the principal crater, located on the edge of the caldera, and there is a choice of seven sites for future stations which will complement with a high level of detail the monitoring of the activity of Chaitén volcano.

The seismicity recorded by the Chaitén volcano network has remained stable, showing a predominance of hybrid (HB) type earthquakes, with an average that has not exceeded 12 earthquakes per hour and with local magnitudes calculated as situated within the range 1.0 to 4.1. It is notable that there were fewer than 1-2 earthquakes per hour with magnitudes of more than 3.5.

3. Conclusions and interpretation

The preceding information indicates a ‘usual’ behaviour within the eruptive cycle of the volcano, indicating that the eruptive activity continues with the growth of the dome complex and the occurrence of possible ‘piston’ type explosions.

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.

OVDAS-SERNAGEOMIN
16 October 2009

[End of SERNAGEOMIN bulletin.]

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

Information
Global Volcanism Program: Chaitén – summary information for Chaitén (1508-41)
SERNAGEOMIN – Servicio Nacional de Geología y Minería (Spanish)
Erupción del Volcán Chaitén – extensive coverage of the Chaitén eruption

The Volcanism Blog

The ecological impact of the Chaitén eruption 27 October 2009

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What follows is a guest post and photo essay (10 images) by Frederick J. Swanson (U.S. Forest Service), Charlie Crisafulli (U.S. Forest Service), Julia A. Jones (Oregon State University) and Nicolas La Penna (Chaitur Excursiones).

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Deservedly, Chaitén volcano at 43° S in Chile has been a popular subject on The Volcanism Blog, but mostly viewed via remote sensing from space or the plume surveillance camera. To give a feeling for on-the-ground conditions, we offer a short photo essay from travels to the area in March 2009 to carry out reconnaissance on ecological effects of the May 2, 2008, eruption. One of our study objectives was to compare ecological responses to the eruption of Chaitén with those observed in the intensively-studied Mount St. Helens landscape since her May 18, 1980, eruption (Dale et al. 2005).

Chaitén and Mount St. Helens have some important similarities in the suites of volcanic processes involved in their major eruptions – lateral blast, tephrafall, and lahars – as well as high levels of water and sediment runoff from tephra-mantled hillslopes (Lipman and Mullineaux 1981, Carn et al. 2009, Lara 2009). (Note: ‘blast’ is used here as a general term for a laterally-directed, rapid movement of sediment-charged air; clearly the volcanic processes were quite different.) The recent eruptions at these two volcanoes differed in several respects, including much more extensive blast and lahars at Mount St. Helens and what appears to be much more extensive forest canopy damage in response to tephrafall at Chaitén. Further, and of substantial ecological importance, were differences in particle size of tephras between the two volcanic eruptions. Mount St. Helens tephra was coarse dacite pumice, whereas Chaitén tephra was very fine rhyolite ash. At both volcanoes these processes have created gradients of disturbance in the forests ranging from complete removal of aboveground vegetation to toppling of trees to killing of standing trees by abrasion and scorching of foliage to a gentle deposition of cool tephra into living forest. Stream and river habitats near the volcano also experienced a range of disturbances, including inundation by fine tephra washed from the hillslopes and severe scour by lahars and floods augmented by rapid runoff from tephra-covered hillslopes. These fluvial processes severely damaged the town of Chaitén and triggered evacuation of its 5000 residents.

As at Mount St. Helens, the severely impacted Chaitén landscape at first appeared lifeless, but we quickly found organisms surviving in a variety of ways and in many locations. Several types of understory plants, such as ferns, nalca, and bamboo, sprouted vigorously from belowground rootstocks. Several species of broadleaf trees, both standing and toppled with limbs removed, were beginning to sprout along the bole. We were surprised by the paucity of evidence of animals, including insects, spiders ballooning in on the winds, birds and burrowing animals, such as the rodents and ants which were common at Mount St. Helens in the first summer after the eruption. More detailed reports from Chaitén are forthcoming; observations at Mount St. Helens are documented in Dale et al. (2005).

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Chaitén imagery at the NASA Earth Observatory 26 October 2009

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Chaiten volcano, 20 October 2009 (NASA EO-1 image)

The NASA Earth Observatory is showcasing a new image of Chaitén volcano in Chile, captured on 20 October 2009 the Advanced Land Imager (ALI) on NASA’s Earth Observing-1 (EO-1) satellite. A reduced-size preview is shown above: Chaitén volcano, marked with the yellow arrow, is producing a white plume that turns to the north-east. Chaitén town, inundated by lahars that have descended the Chaitén river valley from the volcano, can be seen in the lower left of the image. The snow-covered mass on the upper right is Minchinmávida volcano.

The Earth Observatory offers a detail view of Chaitén volcano with labels and an explanatory caption and the full-size version of the image (3 MB, 3000 x 3000 pixels), which shows lots of fascinating detail.

Chaitén volcano, Chile – NASA Earth Observatory (26 October 2009)

[NASA Earth Observatory image created by Jesse Allen, using EO-1 ALI data provided courtesy of the NASA EO-1 team.]

The Volcanism Blog

Dr Jonathan Castro talks Chaitén at Eruptions 26 October 2009

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In a great example of geoblogging outreach, Dr Erik Klemetti of Eruptions recently invited his readers to put questions on the Chaitén eruption to Dr Jonathan Castro. The questions and the answers are now posted at Eruptions, and offer illuminating and fascinating insights into the Chaitén eruption that you won’t find anywhere else. Take a look: Answers to your Chaiten questions from Dr. Jonathan Castro.

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

Information
Global Volcanism Program: Chaitén – summary information for Chaitén (1508-41)
SERNAGEOMIN – Servicio Nacional de Geología y Minería (Spanish)
Erupción del Volcán Chaitén – extensive coverage of the Chaitén eruption

The Volcanism Blog

The view from Chaitén, 15 October 2009 15 October 2009

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Chaiten volcano, 15 October 2009, 18:24

As spring brings better weather in the southern hemisphere, good days for viewing Chaitén volcano through the DGAC camera in Chaitén town become more frequent. Today the weather has been clear and cloudless, and at the time of posting the most recent view (18:24 local time) is as shown above. The width of the plume reflects the wide base from which the emissions are rising.

Earlier today there was evidently a significant partial dome collapse event at around 11:00 which produced a greatly thickened and very dark brown, ash-laden plume (13 pictures in total):

Chaiten volcano, 15 October 2009, 10:41

Chaiten volcano, 15 October 2009, 10:46

Chaiten volcano, 15 October 2009, 10:51

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Chaitén magma’s surprising speed 8 October 2009

Posted by admin in Chaitén, Chile, current research, eruptions, geoscience, natural hazards.
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New research just published in Nature indicates that the magma feeding the eruption of Chaitén that began in May 2008 rose from the magma chamber to the surface much faster than anyone thought, and much faster than sticky, viscous rhyolite magma has any right to move. This makes the Chaitén eruption even more interesting than it was already, and suggests that rhyolitic volcanoes may spring nasty surprises on us in the future by building up to eruption very quickly.

Blognote: Dr Erik Klemetti has all you need to know about Chaitén’s racy rhyolite over at Eruptions, and offers the opportunity to put your questions to one of the authors of the Nature study, Dr Jonathan Castro.

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

Information
Global Volcanism Program: Chaitén – summary information for Chaitén (1508-41)
SERNAGEOMIN – Servicio Nacional de Geología y Minería (Spanish)
Erupción del Volcán Chaitén – extensive coverage of the Chaitén eruption

The Volcanism Blog

Chaitén bulletin no. 107 (1 October 2009) 7 October 2009

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SERNAGEOMIN bulletin no. 107 on the Chaitén eruption, covering the period 16-30 September 2009, has been published and reports the results of an overflight carried out on 29 September, running to a remarkable five pages in length. Among the interesting facts reported: the emergence of a new third lava dome, the appearance of an elongated depression in the central area of the dome complex, and a collapse event on 29 September possibly triggered by the Samoa earthquake.

The original document is available as a PDF via the informes page of the Observatorio Volcanológico de los Andes del Sur (OVDAS) website, and in a shortened version on the main SERNAGEOMIN site. Translation as follows.

CHAITÉN VOLCANO
TECHNICAL BULLETIN NO. 107
16-30 SEPTEMBER 2009
OVDAS-SERNAGEOMIN

1. Visual monitoring

SERNAGEOMIN and ONEMI personnel, carrying out an overflight on 29 September, observed that the volcanic system continues in eruption, with a changing morphology that reflects the growth and collapse of the dome complex (figures 3 and 4). The appearance of a third dome towards the central-southwest portion is notable. The columns of gas and ash, which on occasion reach 2.0 km altitude above the dome complex, show two principal sources of gas and ash emission located in the central part and towards the east of the dome complex. The block-and-ash flows still persist, indicating that the dome complex is very active and has continued to grow. In the course of this period, the images observed through the DGAC camera located in Chaitén to the south of the volcano, show that the gas column has changed its dimensions both in diameter and height, because of the activity itself and the atmospheric conditions.

Figure 1
Fig. 1. Image taken by the DGAC [camera] at dawn on 28 September.

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Chaitén lava domes at the NASA Earth Observatory 2 October 2009

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Lava domes, Chaiten volcano, 30 September 2009 (NASA EO-1 ALI image, courtesy NASA Earth Observatory)

Hot on the heels of the last Chaitén image featured by the NASA Earth Observatory comes this close-up view of the Chaitén lava domes, captured by the Advanced Land Imager (ALI) aboard the Earth Observing-1 (EO-1) satellite on 30 September 2009. In this new image the plume is blowing away to the south, revealing the northern part of the dome complex which was obscured in the earlier image (detail shown below).

Chaiten volcano erupting, 27 September 2009 (NASA EO-1 ALI image, courtesy NASA Earth Observatory)

[NASA images by Robert Simmon, using EO-1 ALI data provided courtesy of the NASA EO-1 team. Thanks to Robert Simmon of the NASA Earth Observatory for referencing this blog in his caption.]

Lava domes, Chaitén volcano – NASA Earth Observatory (2 October 2009)

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

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