Mora-Stock, C., Thorwart, Martin, Wunderlich, Tina, Bredemeyer, Stefan, Hansteen, Thor and Rabbel, Wolfgang (2012) Comparison of volcano-seismic activity in Llaima and Villarrica before and after the Maule M8.8 earthquake in Southern Chile. [Poster] In: The Lübeck Retreat, Collaborative Research SFB 574 Volatiles and Fluids in Subduction Zones: Climate Feedback and Trigger Mechanisms for Natural Disasters. , 23.-25.05.2012, Lübeck . The Lübeck Retreat: final colloquium of SFB 574; May 23-25, 2012: program & abstracts. ; p. 20 .

Abstract

Llaima and Villarrica are two of the most actives volcanoes in the Southern Volcanic Zone in the
Chilean Andes, with different type of activity and edifice. Llaima is a close vent volcano with constant
seismic activity, while Villarrica is an open vent volcano with lava lake at the summit and constant
degassing. The relation between volcano eruptions following a great earthquake has been studied in
different cases around the world, and it has been the case for the 1960 Valdivia earthquake in
southern Chile, where Llaima and Villarrica presented eruptions on the following months to years.
This study characterize the volcano-seismic activity in the months before and after the M8.8 Maule
earthquake. Time series for tremors, long period and volcano tectonic events were obtained from the
catalogue of the Volcanic Observatory of the Southern Andes (OVDAS in Spanish) and from the
continuous record of the SFB 574 temporary volcanic networks. In Villarrica volcano, peaks of activity
of tremor and long period events were observed months prior to and after the earthquake, followed by
degassing activity, which is consistent with an increase in the activity related to fluids (gas and
magma). While in Llaima volcano, a high increase in the volcano tectonic activity was observed
directly after the earthquake, a possible structural adjustment response. Pressure change and normal
stress were calculated for the Maule earthquake (M8.8) giving results two orders of magnitude lower
in comparison to the ones obtained for Valdivia earthquake (M9.5). Giving the sustained activity and
the nature of response, it is possible to state that the Maule earthquake affected these volcanoes in
some way, but given the location and the insufficient critical state of both edifices, it was not possible
to generate a great eruption.

Actions (login required)

View Item