Catching up with Chaitén (and Llaima) 20 November 2009Posted by admin in activity reports, Chaitén, Chile, eruptions, Llaima.
Tags: Chaitén, Chile, Llaima, South America, volcanic activity reports, volcanic eruptions
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.
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.]
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