The recent seismo-volcanic activity at Deception

• Main Authors: Jes!us M. Ib!an Ez, Javier Almendros, Enrique Carmona, Miguel Abril
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2002
• Subjects: Antarctic; Deception Island; South Shetland Islands; Antarc*; Antarctica
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.379.5284; http://hera.ugr.es/doi/1498085X.pdf

This paper reviews the recent seismic studies carried out at Deception Island, South Shetland Islands, Antarctica, which was monitoredby the Argentinean andSpanish Antarctic Programs since 1986. Several types of seismic network have been deployed temporarily during each Antarctic summer. These networks have consisted of a variety of instruments, including radio-telemetered stations, autonomous digital seismic stations, broadband seismometers, and seismic arrays. We have identified two main types of seismic signals generated by the volcano, namely pure seismovolcanic signals, such as volcanic tremor andlong-period(LP) events, andvolcano-tectonic (VT) earthquakes. Their temporal distributions are far from homogeneous. Volcanic tremors and LP events usually occur in seismic swarms lasting from a few hours to some days. The number of LP events in these swarms is highly variable, from a background level of less than 30/day to a peak activity of about 100 events/h. The occurrence of VT earthquakes is even more irregular. Most VT earthquakes at Deception Island have been recorded during two intense seismic crises, in 1992 and 1999, respectively. Some of these VT earthquakes were large enough to be felt by researchers working on the island. Analyses of both types of seismic events have allowed us to derive source locations, establish seismic source models, analyze seismic attenuation, calculate the energy andstress drop of the seismic sources, andrelate the occurrence of seismicity to the volcanic activity. Pure seismo-volcanic signals are modelled as the consequence of hydrothermal