Mapping the Seismicity of Mars With InSight

Abstract

AbstractThe InSight seismometers have recorded more than 1,300 events. Ninety‐eight of these, named the low‐frequency (LF) family, show energy predominantly below 1 Hz down to ∼0.1 Hz. The Marsquake Service identified seismic phases and computed distances for 42 of these marsquakes, 24 of which have backazimuths. Hence, the locations of the majority of LF family events remain undetermined. Here, we use an envelope shape similarity approach to determine event classes and distances, and introduce an alternative method to estimate the backazimuth. In our analysis, we use the highest quality marsquakes with known distances as templates, including the largest event S1222a, and assign new distances to similar group of events for which distance estimates were not previously available. We find the Tharsis region to be more active than initially perceived on the basis of 5 newly located events near Valles Marineris and Olympus Mons. We relocate two marsquakes with little or no S‐wave energy in the NE of the Elysium Bulge. The event epicenters in Cerberus Fossae follow a north‐south trend due to uncertainties in location, while the fault system is in the NW‐SE direction; therefore, these events are re‐projected along the observed fault system based on our interpretations. The marsquakes in our interpreted catalog are predominantly observed in the northern hemisphere of Mars above the equatorial dichotomy boundary.