Constraining marsquake focal mechanisms and martian crustal structure using InSight's seismic data

In early 2019, NASA's InSight lander successfully deployed a single three-component very broadband seismometer (VBB) on the surface of Mars to detect and characterize marsquakes. With the motivation to jointly resolve the focal mechanisms and crustal structure, we analyzed marsquake recordings with a relatively high signal-to-noise ratio (SNR) and a robust distance estimate. These high-quality marsquakes were located either in the vicinity of the Cerberus Fossae or the Orcus Patera regions, with distances ranging from 25° to 43° (±10°). We are using different approaches to invert the waveform data inferring the moment tensor and to explore the compatibility of the observed data with different crustal models. These approaches are based on body-wave coda, a time window of around 30 seconds around the P- and S-wave arrivals. Limited by a small number of recordings from a single station, the separation of propagation effects close to the source from receiver-side effects is one of the main challenges. We found that these marsquakes are all likely the results of an extensional fault regime mainly oriented south-east north-west.