First Focal Mechanisms of Marsquakes

Since February 2019, NASA's InSight lander is recording seismic signals on the planet Mars, which, for the first time, allows to observe ongoing tectonic processes with geophysical methods. A number of Marsquakes have been located in the Cerberus Fossae graben system in Elysium Planitia and further west, in the Orcus Patera depression. We present a first study of the focal mechanisms of three well-recorded events (S0173a, S0183a, S0235b) to determine the processes dominating in the source region. We infer for all three events a predominantly extensional setting. Our method is adapted to the case of a single, multicomponent receiver and based on fitting waveforms of P and S waves against synthetic seismograms computed for the initial crustal velocity model derived by the InSight team. We explore the uncertainty due to the single-station limitation and find that even data recorded by one station constrains the mechanisms (reasonably) well. For the events in the Cerberus Fossae region (S0173a, S0235b) normal faulting with a relatively steep dipping fault plane is inferred, suggesting an extensional regime mainly oriented E-W to NE-SW. The fault regime in the Orcus Patera region is not determined uniquely because only the P wave can be used for the source inversion. However, we find that the P and weak S waves of the S0183a event show similar polarities to the event S0173, which indicates similar fault regimes

Mars Seismic Catalogue, InSight Mission; V3 2020-07-01

The NASA InSight mission installed a single seismic station on the surface of Mars in 2019. The Marsquake Service (MQS) is an official service of the InSight ground services. MQS is tasked with detecting and characterising marsquakes, and curating the catalogue. Waveform data is publicly released on a 3 month schedule. Starting on 2 January, 2020, an updated MQS catalogue is released with each new waveform dataset. This is Data Release 3

Mars Seismic Catalogue, InSight Mission; V1 2/1/2020

The NASA InSight mission installed a single seismic station on the surface of Mars in 2019. The Marsquake Service (MQS) is an official service of the InSight ground services. MQS is tasked with detecting and characterising marsquakes, and curating the catalogue. Waveform data is publicly released on a 3 month schedule. Starting on 2 January, 2020, an updated MQS catalogue is released with each new waveform dataset. This is Data Release 1

Mars Seismic Catalogue, InSight Mission; V3 2020-07-01

The NASA InSight mission installed a single seismic station on the surface of Mars in 2019. The Marsquake Service (MQS) is an official service of the InSight ground services. MQS is tasked with detecting and characterising marsquakes, and curating the catalogue. Waveform data is publicly released on a 3 month schedule. Starting on 2 January, 2020, an updated MQS catalogue is released with each new waveform dataset. This is Data Release 3

Autocorrelation of the ground vibration recorded by the SEIS-InSight seismometer on Mars for imaging and monitoring applications

vEGU21: Gather Online | 19–30 April 2021Since early February 2019, the SEIS seismometer deployed at the surface of Mars in the framework of the NASA-InSight mission has been continuously recording the ground motion at Elysium Planitia. In this work, we take advantage of this exceptional dataset to put constraints on the crustal properties of Mars using seismic interferometry (SI). This method use the seismic waves, either from background vibrations of the planet or from quakes, that are scattered in the medium in order to recover the ground response between two seismic sensors. Applying the principles of SI to the single-station configuration of SEIS, we compute, for each Sol (martian day) and each local hour, all the components of the time-domain autocorrelation tensor of random ambient vibrations in various frequency bands. A similar computation is performed on the diffuse waveforms generated by more than a hundred Marsquakes. For imaging application a careful signal-to-noise ratio analysis and an inter-comparison between the two datasets are applied. These analyses suggest that the reconstructed ground responses are most reliable in a relatively narrow frequency band around 2.4Hz, where an amplification of both ambient vibrations and seismic events is observed. The average Auto-Correlation Functions (ACFs) from both ambient vibrations and seismic events contain well identifiable seismic arrivals, that are very consistent between the two datasets. We interpret the vertical and horizontal ACFs as the ground reflection response below InSight for the compressional waves and the shear waves respectively. We propose a simple stratified velocity model of the crust, which is most compatible with the arrival times of the detected phases, as well as with previous seismological studies of the SEIS record. The hourly computation of the ACFs over one martian year also allows us to study the diurnal and seasonal variations of the reconstructed ground response with a technique call Passive Image Interferometry (PII). In this study we present measurements of the relative stretching coefficient between consecutive ACF waveforms and discuss the potential origins of the observed temporal variations

Magnitude Scales for Marsquakes Calibrated from InSight Data

A recalibration of the seismic magnitude scales for Marsquakes in the light of events recorded by InSight

Mars Seismic Catalogue, InSight Mission; V2 2020-04-01

The NASA InSight mission installed a single seismic station on the surface of Mars in 2019. The Marsquake Service (MQS) is an official service of the InSight ground services. MQS is tasked with detecting and characterising marsquakes, and curating the catalogue. Waveform data is publicly released on a 3 month schedule. Starting on 2 January, 2020, an updated MQS catalogue is released with each new waveform dataset. This is Data Release 2

Super high frequency events: a new class of events recorded by the InSight seismometers on Mars

International audienceWe present a new class of seismic signals that are recorded by the seismometer placed on the surface of Mars as part of the NASA InSight mission. The signals, termed super high frequency (SF) events, are of short duration (∼20 s), are often similar in amplitude, and feature high frequency energy between ∼5 and 30 Hz that is dominant on the horizontal components. For detection and characterization of SF events, we employ the available continuous 20 samples per second (sps) data from the Very Broadband instrument. Due to bandwidth limitations, 100 sps data from the short period sensor are only partially obtainable, but they aid in analysis of the frequency content above 10 Hz and in distinguishing the events from high frequency noise. From June 2019 to May 2020, 780 SF events have been detected. The events observed occur in repeatable patterns that last for weeks. Initially, the SF events were clustered in the hours before sunset, but more recently, they have been distributed across the evening period. Based on template matching techniques, we have identified 16 distinct families that generally follow the temporal clusters. A thermal origin of these events is suggested, since the majority of the events fall within a ±2 h time window around sunset with extreme temperature changes. The SF events have similarities with thermal events observed on the lunar surface from data collected during the Apollo missions

High frequency seismic events on Mars observed by InSight

International audienc