Systematic Comparison of Hypocenter and Centroid Parameters of Earthquakes Along the South American Plate Boundary

Abstract

We present a statistical and empirical analysis of the earthquake source parameters from the International Seismological Centre (ISC) and Global Centroid Moment Tensor (GCMT) catalogs. Source parameter data are collected for the subduction zones of South America and the Nazca Plate for the time frame 1976 to 2016. The source parameter data for this region are compiled to develop a series of empirical relationships among hypocenter location, centroid attributes, depth, moment magnitude, azimuth, earthquake origin time, rupture length, and hypocenter–centroid distance. In this analysis, only events common to both catalogs are included. In the correlation of different source parameters, we observed the following notable results: (1) hypocenter–centroid distance is constant with moment magnitude, but rises gradually beyond higher magnitudes; (2) origin-time residual gradually increases with moment magnitude, but grows linearly with a higher slope for higher magnitudes; (3) azimuths of the distance vector cluster predominantly around \(250^\circ\). Additional regression and spatial analyses highlight systematic patterns of seismic behavior unique to this subduction boundary.