Short Term Changes in Shear Wave Splitting at Sierra Negra Volcano, 2010: Possible Indicator of a Magmatic Intrusion

Abstract:

The Sierra Negra volcano, Galapagos, is a basaltic shield volcano with the largest caldera (7x10 km) in the islands. Frequent eruptions have been dated, with a time interval between them typically in the order of decades (7 were confirmed in the last century), the last one occurred in 2005. We present new results from a shear wave splitting study performed at Sierra Negra volcano using nearly two years (Aug 2009-Jun 2011) of data obtained from SIGNET (Sierra Negra Integrated Geophysical Network) project. Changes in fast shear wave polarity are detected during the period of 4-10 June 2010, which are interpreted as the result of a crustal (6-10 km) magmatic intrusion event. The goal of this study was to determine the state of crustal stress at and around Sierra Negra in order to establish how different possible stress sources (ie the Galapagos spreading center, the Nazca plate movement along the insular platform …

Año de publicación:

2012

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