Quantifying the sensitivity of microearthquake slip inversions to station distribution using a dense nodal array

Bulletin of the Seismological Society of America
By: , and 

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Abstract

To investigate the sensitivity of slip inversions to station distribution and choice of empirical Green’s function (EGF), we examine three microearthquakes that occurred within the high‐density LArge‐n Seismic Survey in Oklahoma (LASSO) nodal seismic array. The LASSO array’s dense distribution of 1825 geophones provides an exceptional level of spatial and azimuthal coverage, allowing for more accurate inversions of slip than are possible with typical station distributions. The highly accurate slip inversions, in turn, allow for the exploration of the sensitivity of slip inversions to station distribution and parameter choices. We examine the effects of these choices using three well‐recorded strike‐slip microearthquakes (ML 1.7, 2.3, and 2.7) using an EGF method. From this analysis and the systematic testing of varied network arrangements, we find that station distributions that have uniform coverage of azimuth and distance can retrieve the overall pattern of slip, but the estimated amplitude of slip can vary by 30% for high‐slip regions due to small variations in station location. In addition, we find that the distance range that accurately resolves the overall pattern of slip is the one that contains the takeoff angles of 45°–65°. Concerning azimuthal coverage, a network with >270° performs similarly to having complete coverage. The choice of EGF can shift the location of resolved areas of slip and their amplitude, depending on its similarity in location and radiation pattern to the target earthquake.

Publication type Article
Publication Subtype Journal Article
Title Quantifying the sensitivity of microearthquake slip inversions to station distribution using a dense nodal array
Series title Bulletin of the Seismological Society of America
DOI 10.1785/0120210279
Volume 112
Issue 3
Year Published 2022
Language English
Publisher Seismological Society of America
Contributing office(s) Earthquake Science Center
Description 18 p.
First page 1252
Last page 1270.
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