Locating the Largest Event Observed on Mars With Multi‐Orbit Surface Waves
M. P. Panning, W. B. Banerdt, Caroline Beghein, Sebastián Carrasco, Savas Ceylan, John Clinton, Paul M. Davis, M. Drilleau, Domenico Giardini, A. Khan, Doyeon Kim, Brigitte Knapmeyer‐Endrun, Jiaqi Li, Philippe Lognonné, Simon C. Stähler, Géraldine Zenhäusern
Abstract
Abstract Prior to the 2018 landing of the InSight mission, the InSight science team proposed locating Marsquakes using multiple orbit surface waves, independent of seismic velocity models, for events larger than M W 4.6. The S1222a M W 4.7 of 4 May 2022 is the largest Marsquake recorded and the first large enough for this method. Group arrivals of the first three orbits of Rayleigh waves are determined to derive the group velocity, epicentral distance, and origin time. The mean distance of 36.9 ± 0.3° agrees with the Marsquake Service (MQS) distance based on body wave measurements of 37.0 ± 1.6°. The origin time from surface waves is systematically later than the MQS origin time by 20 s. Backazimuth estimation is similar to body wave estimations from MQS although suggesting a shift to the south. Backazimuth estimates from R2 and R3 are more scattered, but do show clear elliptical motion.