Using Data from InSight to Locate and Explain Marsquakes

We took advantage of seismic data collected and reported by the Marsquake Service (MQS) to create a visual catalog of waveform data from the InSight mission and characterize signals’ origins. Four low frequency events were tagged as strong signals between 1-Jan-2019 and 31-Dec-2019. One of these events was originally thought to be a single event but after careful analysis, a shift in the point of origin overtime indicated that this was a series of two events occurring in quick succession. These four events, S0173a, S0235b, S0325aa, S0325ab were then located and an estimate of the faulting mechanism was made that could explain the different waveform amplitudes. The strongest of the events were S0173a, occurring on 23-May-2019, and S0235b, occurring on 26-July-2019. They were found to be located 29° and 27.5° from the lander with back azimuths estimations of 91° and 74° respectively. These locations indicate these events originated east of the lander near the Cerberus Fossae region, which is in agreement with estimates provided by MQS. We located the third and fourth events on 26-Oct-2019 to the south east and east of the lander due to their respective back azimuths estimations of 123° and 110°. With a distance of 38.5°, S0325aa was found to fall on the boundary between the Martian highlands and lowlands. S0325ab, however, was found to have a distance of 33.6° which is neither in the Cerberus Fossae region or along the highland lowland transition. Based on modeled arrival angles using the Martian interior model named Gudkova, the amplitude ratios of the main body wave phases P and S for all four events align most closely to dip-slip faulting mechanisms with vertical, or near vertical in the case of S0173a, fault planes.