Registro de resúmenes

Reunión Anual UGM 2023


SIS-29

 Resumen número: 0040  |  Resumen aceptado  
Presentación oral

Título:

INSIGHT INTO EARTHQUAKE SOURCE PROCESSES FROM MOMENT TENSOR CATALOGS

Autor:

Boris Rösler
Centro de Investigación Científica y de Educación Superior de Ensenada, CICESE
info@boris.net

Sesión:

SIS Sismología Sesión regular

Resumen:

Analysis of moment tensor catalogs gives insight into general properties of many earthquakes beyond what can be obtained by studies of individual earthquakes and allows estimating uncertainties in the determination of seismic source processes. Traditionally, uncertainties in moment tensors are derived from the misfit between observed and synthetic waveforms. However, the differences between moment tensors in the USGS and the Global CMT Project catalogs are typically an order of magnitude larger than the reported errors, suggesting that the reported errors substantially underestimate the uncertainty due to different inversion procedures. Differences between double-couple (DC) components decrease with magnitude, and correlation between non-double-couple (NDC) components increases, suggesting that seismic sources of large earthquakes are determined more reliably. A dataset compiled from three global and four regional catalogs shows that NDC components are essentially independent of magnitude for earthquakes over a large magnitude range, with a mean deviation from a DC source of about 20%. Additionally, there is essentially no difference in NDC components between earthquakes with different fault mechanisms and in different geologic environments. This consistency indicates that most NDC components, especially for smaller earthquakes, do not reflect real source processes and are likely to be artifacts of the inversion. Through comparison of moment tensors from three global catalogs, I find that NDC components of large earthquakes are more reliably determined, and that the largest NDC components are more likely to represent real source processes. The correlation of NDC components in different catalogs allows quantifying the noise contained in them and thus determination which catalog provides the most precise NDC components.





Reunión Anual UGM 2023
29 de Octubre al 3 de Noviembre
Puerto Vallarta, Jalisco, México