Multiparameter surveillance of Villarrica volcano

Abstract

Villarrica is one of the most active volcanoes in Chile and one of the few in the world with an active lava lake within its crater. This snow-covered volcano generates frequent strombolian eruptions and lava flows and, at times, the melting of snow can cause massive lahars. The most common types of activity at Villarrica are, however, continuous degassing and high-level seismicity. In order to investigate the mechanisms driving the persistent degassing and seismic activity at the volcano, we use a multiparameter approach based on high time-resolution gas flux measurements and seismic data. The instrumentation includes 3 stationary NOVAC-type scanning Mini-DOAS spectrometers for the quantification of SO2 fluxes, installed at the volcano in March 2009, and 7 short period and broadband seismometers. This equipment complements the existing OVDAS (Observatorio Volcanológico de los Andes del Sur) volcano monitoring network. Based of the combination of gas and seismological measurements we aim at gaining insight into magmatic and volcano- tectonic processes, especially factors playing a role for the onset of volcanic unrest. Since the gas monitoring network has been installed at the volcano a correlation between SO2 emissions and seismic activity (LP events) has been recognized. We currently investigate a possible influence of regional tectonic activity on changes detected in degassing rates and seismicity, and consequently on volcanic activity