Seismo-tectonic structure of the Aysen Region, Southern Chile, inferred from the 2007 Mw=6.2 Aysen earthquake sequence
Por:
Agurto H., Rietbrock A., Barrientos S., Bataille K., Legrand D.
Publicada:
1 jul 2012
Resumen:
On 2007 April 21, a Mw= 6.2 earthquake shook the Aysen Fjord, Southern Chile in an unprecedented episode for this region characterized by low seismicity. The area is intersected by the Liquine-Ofqui Fault System (LOFS), a +1000-km-long strike-slip fault that absorbs part of the oblique convergence motion between Nazca and South America plates. To study the aftershock sequence of this main event, we installed a seismic network of 15 stations in the area for a period of nearly 7 months. We characterized the seismogenic structure of the zone by calculating a minimum 1-D local velocity model and obtaining precise hypocentral coordinates and uncertainty estimates by using a non-linear probabilistic approach. We also obtained fault plane solutions based on first motion polarities and SV/P amplitude ratios. The velocity model shows an average Vp/Vs ratio of 1.76 for the area and low shear wave velocity values for the upper 3 km of crust. The aftershock seismicity was located mainly between 4
Filiaciones:
Agurto H.:
School of Environmental Sciences, University of Liverpool, Liverpool, L69 3GP, United Kingdom
Rietbrock A.:
School of Environmental Sciences, University of Liverpool, Liverpool, L69 3GP, United Kingdom
Barrientos S.:
Departamento de Geofísica, Universidad de Chile, Santiago, Chile
Bataille K.:
Departamento Ciencias de la Tierra, Universidad de Concepción, Concepción, Chile
Legrand D.:
Univ Nacl Autonoma Mexico, Dept Vulcanol, Inst Geofis, Mexico City, DF, Mexico
Bronze
|