Improving Seismic Source Characterization of Moderate Magnitude Events at Regional Distance With Seismic and InSAR Data

While technologies such as satellite imaging are used in addition to seismic data for large magnitude earthquakes to confirm fault mechanisms, they are significantly less considered for the analysis of smaller sized events. However, constraining the nature of small to moderate magnitude seismic events with a sparse seismic network presents a significant challenge for monitoring agencies. The limitation in seismic coverage as well as low signal-to-noise levels measured in seismic data imply significant uncertainties in accurately estimating the source parameters (i.e., epicentral position, depth, magnitude and mechanism: earthquake, explosion, collapse). Quantifying and reducing these uncertainties becomes paramount, especially for the monitoring of shallow underground nuclear tests.

Here, we explore the advantages of combining seismic data and satellite borne Synthetic-Aperture-Radar-Interferometry (InSAR) techniques to recover the source parameters of superficial geophysical events using moment tensor techniques. We present the work we have undertaken for different types of shallow seismic events including earthquakes and collapses. From the acquisition of satellite images and seismic data to the comparison of the source solutions provided by both datasets, we explore the strengths and weaknesses of each approach that still need to be understood, and we propose joint approaches where possible. In the future, joint seismic-InSAR full moment tensor inversions may lead the way in the monitoring of regions with low seismic coverage.