Chaitén and Llaima updates from SERNAGEOMIN (17 April 2009)

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