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SEIS, the seismometer of the InSight mission, which landed on Mars on 26 November 2018, is monitoring the seismic activity of the planet. The goal of the Mars Structure Service (MSS) is to provide, as a mission product, the first average 1-D velocity model of Mars from the recorded InSight data. Prior to the mission, methodologies have been developed and tested to allow the location of the seismic events and estimation of the radial structure, using surface waves and body waves arrival times, and receiver functions. The paper describes these validation tests and compares the performance of the different algorithms to constrain the velocity model below the InSight station and estimate the 1-D average model over the great circle path between source and receiver. These tests were performed in the frame of a blind test, during which synthetic data were inverted. In order to propagate the data uncertainties on the output model distribution, Bayesian inversion techniques are mainly used. The limitations and strengths of the methods are assessed. The results show the potential of the MSS approach to retrieve the structure of the crust and underlying mantle. However, at this time, large quakes with clear surface waves have not yet been recorded by SEIS, which makes the estimation of the 1-D average seismic velocity model challenging. Additional locatable events, especially at large epicentral distances, and development of new techniques to fully investigate the data, will ultimately provide more constraints on the crust and mantle of Mars.

Convective vortices (whirlwinds) and dust devils (dust‐loaded vortices) are one of the most common phenomena on Mars. They reflect the local thermodynamical structure of the atmosphere and are the driving force of the dust cycle. Additionally, they cause an elastic ground deformation, which is useful for retrieving the subsurface rigidity. Therefore, investigating convective vortices with the right instrumentation can lead to a better understanding of the Martian atmospheric structures as well as the subsurface physical properties. In this study, we quantitatively characterized the convective vortices detected by NASA's InSight (∼13,000 events) using meteorological (e.g., pressure, wind speed, temperature) and seismic data. The evaluated parameters, such as the signal‐to‐noise ratio, event duration, asymmetricity of pressure drop profiles, and cross‐correlation between seismic and pressure signals, are compiled as a catalog. Using these parameters, we investigated (a) the vortex structure and (b) the subsurface physical properties. Regarding the first topic, we tried to illustrate the vertical vortex structure and its link to the shape of the pressure profiles by combining the asymmetrical features seen in the observed pressure drops and the terrestrial observations of dust devils. Our results indicate that most of the vortices move with the wall tilted in the advection direction. Concerning the second topic, selecting the highly correlated events between pressure perturbation and ground response, we estimated the subsurface rigidity at the InSight landing site down to 100 m depth. Our results indicate that the subsurface structure can be modeled with two layers having a transition at 5–15 m depth. Plain Language Summary: As frequently observed on Earth, convective vortices or dust‐loaded vortices are also seen on Mars. They reflect the local atmospheric structure and are the main driving force to lift the fine dust from the ground. In 2018, NASA's InSight succeeded in installing the meteorological and geophysical packages on Mars. That brought us, in particular, meteorological data with an extremely high temporal resolution, contributing to resolving local phenomena such as convective vortices. In this study, using InSight's meteorological (e.g., pressure, air temperature) and seismic data, we quantitatively characterize convective vortices to understand this phenomenon from both meteorological and geophysical aspects. Especially focusing on the asymmetricity of pressure drop profiles at vortex encounters and the correlation between the pressure variations and seismic signals, we investigated (a) a link between the shape of pressure drop profiles and the vertical vortex structure and (b) the ground rigidity structure by measuring the ground responses against the vortex‐related pressure variations. Consequently, first, we found that most of the vortices move with the wall tilted in the advection direction. Second, our results indicated that the subsurface structure can be modeled with two layers down to 100 m with a transition at 5–15 m depth. Key Points: We quantitatively characterized the Martian convective vortices observed by InSight's seismometer and meteorological instrumentsFocusing on the pressure drop profiles, we inferred a link between the asymmetricity and the vertical vortex structureWith the cataloged parameters, we performed a compliance analysis and evaluated the ground rigidity at the InSight landing site [ABSTRACT FROM AUTHOR]

Estimating the rupture process of a quake constrains the tectonic setting of its source region. In terrestrial seismology, the rupture process can be described with a classical ω2 model. In this study, we focus on one key source parameter of S1222a, the corner frequency, to investigate its origin. However, estimating the corner frequency of S1222a is complicated by S1222a's non‐classical spectra which deviate from the ω2 model. To explain S1222a's spectra, we take into account the site effect at the InSight landing site. Through numerical simulation, we demonstrate that the spectral fitting is greatly improved after considering the site effect. We further estimated the source spectrum and stress drop of S1222a. The obtained stress drop resembles the values for regional tectonic earthquakes and shallow moonquakes but differs from the Cerberus Fossae marsquakes, which favors a different tectonic origin from the Cerberus Fossae marsquakes for S1222a. Plain Language Summary: The source of a quake is a key piece of information to uncover the dynamic process at the source region. In terrestrial seismology, the source of a quake can be described with a classical model in which the spectra decay with frequency at a certain speed. In this study, we focus on one key source parameter of S1222a, the corner frequency, to explore the generating process of S1222a. However, S1222a exhibits non‐classical spectra which cannot be explained by the classical model, making it difficult to estimate S1222a's source spectrum. To explain S1222a's spectra, we hypothesized that the seismic records are contaminated by wave reverberations in the subsurface layers, namely site effect. We validated our hypothesis with a numerical method. After considering site effect, S1222a's source spectrum and stress drop can be better estimated. The obtained stress drop value is close to those for regional tectonic earthquakes and shallow moonquakes but differs from the values observed for some marsquakes located at Cerberus Fossae, a seismically active region on Mars. Thus, we conclude that S1222a has a different tectonic origin from the Cerberus Fossae marsquakes. Key Points: We constructed a numerical model to simulate the site effect at the InSight landing site to better explain the spectra of S1222aWe estimated the corner frequency of S1222a to be 0.76 (0.58–1.07) Hz, which corresponds to a stress drop of 3.62 (0.80–20.26) MPaThe corner frequency and stress drop estimation favor that S1222a has a different tectonic origin from the Cerberus Fossae marsquakes [ABSTRACT FROM AUTHOR]

NASA's Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) mission records several high‐frequency (>0.5 Hz) dispersive seismic signals on Mars. These signals are due to the acoustic‐to‐seismic coupling of infrasound generated by the entry and impact of meteorites. This dispersion property is due to infrasound propagating in a structured atmosphere, and we refer to this dispersive infrasound as guided infrasound. We propose to model the propagation of guided infrasound and the seismic coupling to the ground analytically; we use a 1D layered atmosphere on a three‐layer solid subsurface medium. The synthetic ground movements fit the observed dispersive seismic signals well and the fitting indicates that the regolith beneath InSight is about 40‐m in thickness. We also examine and validate the previously‐published subsurface models derived from InSight ambient seismic vibration data. Plain Language Summary: Under particular weather conditions, the Martian atmosphere displays a special sound‐wave velocity profile, where the wave velocity becomes larger with increasing altitude within a few hundred meters. When an infrasound signal—a low‐frequency (<20 Hz) sound wave inaudible to humans—propagates through such a structure, the infrasound exhibits dispersion: its propagation velocity depends on its frequency. We refer to such infrasound as guided infrasound. Guided infrasound can deform the ground, and have been recorded by the seismometer of NASA's Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) mission on the Martian surface. We propose to model these recordings using the physics of sound waves traveling above a compliant solid ground. We show that our modeling results can fit well the seismic recordings of guided infrasound on Mars. We apply our modeling to the subsurface models from a different InSight seismic observation to check if these models can explain our seismic recordings. This modeling constitutes a new tool to investigate the subsurface structure of Mars, and is also useful for the investigation of Titan and Venus. Key Points: We analytically compute the dispersion relationship of guided infrasound in 1D atmospheric models from Mars and EarthWe model the ground response to guided infrasound to fit the corresponding seismic observation due to meteorite impacts on MarsWe utilize the seismic recording due to guided infrasound to constrain the subsurface structures [ABSTRACT FROM AUTHOR]

The entry, descent, and landing (EDL) sequence of NASA's Mars 2020 Perseverance Rover will act as a seismic source of known temporal and spatial localization. We evaluate whether the signals produced by this event will be detectable by the InSight lander (3,452 km away), comparing expected signal amplitudes to noise levels at the instrument. Modeling is undertaken to predict the propagation of the acoustic signal (purely in the atmosphere), the seismoacoustic signal (atmosphere‐to‐ground coupled), and the elastodynamic seismic signal (in the ground only). Our results suggest that the acoustic and seismoacoustic signals, produced by the atmospheric shock wave from the EDL, are unlikely to be detectable due to the pattern of winds in the martian atmosphere and the weak air‐to‐ground coupling, respectively. However, the elastodynamic seismic signal produced by the impact of the spacecraft's cruise balance masses on the surface may be detected by InSight. The upper and lower bounds on predicted ground velocity at InSight are 2.0 × 10−14 and 1.3 × 10−10 m s−1. The upper value is above the noise floor at the time of landing 40% of the time on average. The large range of possible values reflects uncertainties in the current understanding of impact‐generated seismic waves and their subsequent propagation and attenuation through Mars. Uncertainty in the detectability also stems from the indeterminate instrument noise level at the time of this future event. A positive detection would be of enormous value in constraining the seismic properties of Mars, and in improving our understanding of impact‐generated seismic waves. Plain Language Summary: When it lands on Mars, NASA's Perseverance Rover will have to slow down rapidly to achieve a safe landing. In doing this, it will produce a sonic boom and eject two large balance masses which will hit the surface at very high speed. The sonic boom and balance mass impacts will produce seismic waves which will travel away from Perseverance's landing site. Here, we evaluate whether these seismic waves will be detectable by instruments on the InSight lander (3,452 km away). We predict that the waves from the balance mass impacts may be detectable. If the waves are recorded by InSight, this would represent the first detection of ground motion generated by a seismic source on Mars at a known time and location. This would be of enormous value in advancing our understanding of the structure and properties of Mars' atmosphere and interior as well as in improving our understanding of how seismic waves are produced by meteorites hitting the surface. Key Points: The entry descent and landing of Mars 2020 (NASA's Perseverance Rover) will act as a seismic source on Mars act as a seismic source on MarsWe evaluate the detectability of the acoustic (atmospheric) and elastodynamic seismic (ground) signalsWe predict the acoustic signal will not likely be detectable by InSight, but the seismic signal may be [ABSTRACT FROM AUTHOR]

NASA's InSight mission is the first lander to deploy a seismometer on a planetary body since more than 40 years. With a year of seismic data from Mars, new discoveries on Mars' tectonics and interior structure are just emerging. [ABSTRACT FROM AUTHOR]

The InSight (In terior Exploration using S eismic I nvestigations, G eodesy and H eat T ransport) mission landed on the surface of Mars on November 26, 2018. One of the scientific instruments in the payload that is essential to the mission is the SEIS package (Seismic Experiment for Interior Structure) which includes a very broadband and a short period seismometer. More than one year since the landing, SEIS continues to be fully operational and has been collecting an exceptional data set which contains not only the signals of seismic origins, but also noise and artifacts induced by the martian environment, the hardware on the ground that includes the seismic sensors, and the programmed operational activities of the lander. Many of these non-seismic signals will be unfamiliar to the scientific community. In addition, many of these signals have signatures that may resemble seismic events either or both in time and frequency domains. Here, we report our observations of common non-seismic signals as seen during the first 478 sols of the SEIS data, i.e. from landing until the end of March 2020. This manuscript is intended to provide a guide to scientists who use the data recorded on SEIS, detailing the general attributes of the most commonly observed non-seismic features. It will help to clarify the characteristics of the seismic dataset for future research, and to avoid misinterpretations when searching for marsquakes. • This paper is a summary of the InSight data from Mars, mainly focusing on the seismic data set. • We describe the signals of non-seismic origins that potentially can cause misinterpretations as marsquakes. • We outline the common features in the data such as artifacts and patterns for future reference that may be unfamiliar to the scientific community. [ABSTRACT FROM AUTHOR]

The InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) mission began collecting high quality seismic data on Mars in February 2019. This manuscript documents the seismicity observed by SEIS, InSight's seismometer, from this time until the end of March 2020. Within the InSight project, the Marsquake Service (MQS) is responsible for prompt review of all seismic data collected by InSight, detection of events that are likely to be of seismic origin, and curation and release of seismic catalogues. In the first year of data collection, MQS have identified 465 seismic events that we interpret to be from regional and teleseismic marsquakes. Seismic events are grouped into 2 different event families: the low frequency family is dominated by energy at long period below 1 s, and the high frequency family primarily include energy at and above 2.4 Hz. Event magnitudes, from Mars-specific scales, range from 1.3 to 3.7. A third class of events with very short duration but high frequency bursts have been observed 712 times. These are likely associated with a local source driven by thermal stresses. This paper describes the data collected so far in the mission and the procedures under which MQS operates; summarises the content of the current MQS seismic catalogue; and presents the key features of the events we have observed so far, using the largest events as examples. • The Marsquake Service is providing updated catalogues of Martian seismicity as recorded on InSight. • 465 distant marsquakes have been identified in the first 478 martian days (sol) since InSight landed. • This version of the catalogue includes an additional 712 events that may be due to local cracking from thermal forcing. [ABSTRACT FROM AUTHOR]