Differences in Epicentral Location of Mexican Earthquakes between Local and Global Catalogs: An update
Por:
Hjoerleifsdottir, Vale, Singh, Krishna, Husker, Allen
Publicada:
1 ene 2016
Resumen:
Differences in epicentral locations between local and global catalogs
for earthquakes in the Mexican subduction zone were first observed to be
biased in the 1980s, based on a few well studied events. In this study
we compare locations between two local catalogs; (1) a recent high
precision catalog of events in the state of Guerrero and (2) the catalog
of the Servicio Sismologico Nacional (SSN), to the global catalog of the
United States Geological Service (USGS). We find that on average
epicentral locations in the global catalog of earthquakes larger than M
5 in the Mexican subduction zone are 26 km towards N54 degrees E of
those in the local catalogs. We investigate how the errors vary for
different types of earthquakes in Guerrero, and how they vary along the
trench, from the state of Jalisco to the state of Chiapas. The average
differences are largest for thrust events occurring close to the trench,
and for events in Michoacan. The differences are greater on average for
large earthquakes than for small. There is a trade-off between the
distance from the trench and timing, suggesting a poor resolution of
these parameters, due to the lack of stations the Pacific Ocean. We
attribute the differences in locations to systematic patterns in the
velocity structure of the mantle, with consistently fast paths to the
northeast and relatively slow paths towards the southwest.
Filiaciones:
Hjoerleifsdottir, Vale:
Univ Nacl Autonoma Mexico, Inst Geofis, Mexico City 04510, DF, Mexico
Singh, Krishna:
Univ Nacl Autonoma Mexico, Inst Geofis, Mexico City 04510, DF, Mexico
Husker, Allen:
Univ Nacl Autonoma Mexico, Inst Geofis, Mexico City 04510, DF, Mexico
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