Local and regional minimum 1D models for earthquake location and data quality assessment in complex tectonic regions: application to Switzerland |
| |
Authors: | Stephan Husen Edi Kissling John F Clinton |
| |
Institution: | (1) Swiss Seismological Service, ETH Zurich, Sonneggstr. 5, 8092 Zurich, Switzerland;(2) Institute of Geophysics, ETH Zurich, Sonneggstr. 5, 8092 Zurich, Switzerland |
| |
Abstract: | One-dimensional (1D) velocity models are still widely used for computing earthquake locations at seismological centers or
in regions where three-dimensional (3D) velocity models are not available due to the lack of data of sufficiently high quality.
The concept of the minimum 1D model with appropriate station corrections provides a framework to compute initial hypocenter
locations and seismic velocities for local earthquake tomography. Since a minimum 1D model represents a solution to the coupled
hypocenter-velocity problem it also represents a suitable velocity model for earthquake location and data quality assessment,
such as evaluating the consistency in assigning pre-defined weighting classes and average picking error. Nevertheless, the
use of a simple 1D velocity structure in combination with station delays raises the question of how appropriate the minimum
1D model concept is when applied to complex tectonic regions with significant three-dimensional (3D) variations in seismic
velocities. In this study we compute one regional minimum 1D model and three local minimum 1D models for selected subregions
of the Swiss Alpine region, which exhibits a strongly varying Moho topography. We compare the regional and local minimum 1D
models in terms of earthquake locations and data quality assessment to measure their performance. Our results show that the
local minimum 1D models provide more realistic hypocenter locations and better data fits than a single model for the Alpine
region. We attribute this to the fact that in a local minimum 1D model local and regional effects of the velocity structure
can be better separated. Consequently, in tectonically complex regions, minimum 1D models should be computed in sub-regions
defined by similar structure, if they are used for earthquake location and data quality assessment. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|