Megathrust asperities and clusters of slab dehydration identified by spatiotemporal characterization of seismicity below the Andean margin
Por:
Legrand D., Tassara A., Morales D.
Publicada:
1 dic 2012
Resumen:
The spacetimesize distributions of seismicity during the last four decades (19732010) are used to identify megathrust asperities, the degree of plate coupling (hence potential future large earthquakes) and slab dehydration below the Andean margin (15 degrees 48 degrees S). This seismicity displays globally a typical magnitude distribution with a b value of 1.04 +/- 0.024, for a magnitude of completeness of 4.5 and without considering aftershock sequences. However, this unitary b value of the entire catalogue masks large variations (0.61.7) in space and time, interpreted as related to different tectonics contexts or different states of the seismic cycle. The study has been performed for different regions (upper continental plate, upper and lower parts of the subducting oceanic plate) with respect to a 3-D slab geometry model all along the Andean margin. Low b values (0.60.8) are observed in areas that were ruptured by large Mw= 7.5 megathrust earthquakes. A temporal analysis of these fe
Filiaciones:
Legrand D.:
Univ Nacl Autonoma Mexico, Inst Geofis, Dept Vulcanol, Mexico City 04510, DF, Mexico
Tassara A.:
Universidad de Concepción, Departamento de Ciencias de la Tierra, Victor Lamas 1209, Concepción, Chile
Morales D.:
Universidad de Concepción, Departamento de Ciencias de la Tierra, Victor Lamas 1209, Concepción, Chile
Bronze
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