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The InSight lander successfully delivered geophysical instrument package on the Martian surface on November 26th, 2018, including a broadband and a short-period seismometer (Seismic Experiment for Interior Structure, SEIS). The seismic instrument package is specifically designed to record marsquakes and meteoritic impacts in Martian conditions. Routine operations are split into two services: the Mars Structure Service (MSS) and the Marsquake Service (MQS), which are responsible for defining structure models and seismicity catalogs, respectively. The first "deliverable" of the MSS will be a model based on the events detected during the first 3 months of seismic monitoring of the mission, for which only a few quakes might be expected based on current estimates of Mars seismic activity. To test our approach of determining the interior model of Mars and to prepare the InSight science team for data return, we made use of a "blind test" time series for which the Marsquake parameters (location, depth, origin time, and moment tensor) and interior model were unknown to the group at large.In preparation for the mission, the goal was to develop mature algorithms to handle the data as efficiency as possible. Synthetic seismic waveforms were computed in a 1D mantle model with a 3D crust on top using AxiSEM and Salvus. The time series were created by adding seismic noise that relies on pre-landing estimates of noise generated by the sensors, electronic system, environment, and nearby lander. To characterize what we could learn about Mars interior structure with only one station and with the first seismic event, we performed inversions of a synthetic data following a blind test process, where the interior model was unknown to all team members carrying out data analysis and inversion. We detail and compare the results of this "blind test" using different methods including inversion of surface wave dispersion data, body waves travel times, and the waveforms themselves. We have used mainly Bayesian techniques to obtain robust probability density functions of interior structure parameters. The effects on the retrieved model distributions of fixing mars quake location and origin time are investigated, as is the effect of using fixed Vs flexible parameterizations. To allow for tighter constraints, we also test the use of priors based on thermodynamically-constrained models together with seismic observations, as well as seismic confirmation/rejection of models purely based on thermodynamical modelling. These techniques considered here form a large part of the planned modeling of the MSS that will be ultimately employed with the first recording of a seismic event by InSight. [ABSTRACT FROM AUTHOR]

ABSTRACT Garlan, T.; Mathias, X.; Brenon E.; Favretto-Cristini, N.; Deschamps, A.; Beucler, E., Guyomard P., and Morio, O., 2018. Circular sedimentary figures of anthropic origin in a sediment stability context. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 411–415. Coconut Creek (Florida), ISSN 0749-0208. The French POSA project studies the seismic energy released by bomb and mine blasting. This project is based on seismological and acoustical measurements recording during blasting actions in order to study seismic wave propagation nucleated by controlled sources (location and explosive energy). These measurements are compared to numerical modeling of the acoustic and seismic wave propagation based on the most faithful 3D representation of the seabed sediments and underlying rocks. This project first focused on the 3D environment representation based on specific surveys and on two blasting experiments which consist in exploding bombs of different loads at two distinct environmental places. The in-situ measurements reveal several hundred circular figures with very specific characteristics which clearly differentiate them from other sedimentary, biological and geological figures encountered on the seabed. They are found within the whole studied area and their diameter is from 10 to 130 m. About 30 circles by kilometer square are observed without correlation with the depth which varies from 10 to 150m. These sedimentary structures indicate that they have been generated by the explosion of bombs, but at different periods. The oldest ones most probably result from bombs dropped in 1940 and 1944 during the landing of the Allied forces in the region of Toulon. These original anthropic sedimentary figures and their differences compared with other circular structures observed on the seabed are described. [ABSTRACT FROM AUTHOR]

Garlan, T.; Mathias, X.; Brenon E.; Favretto-Cristini, N.; Deschamps, A.; Beucler, E., Guyomard P., and Morio, O., 2018. Circular sedimentary figures of anthropic origin in a sediment stability context. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 411–415. Coconut Creek (Florida), ISSN 0749-0208. The French POSA project studies the seismic energy released by bomb and mine blasting. This project is based on seismological and acoustical measurements recording during blasting actions in order to study seismic wave propagation nucleated by controlled sources (location and explosive energy). These measurements are compared to numerical modeling of the acoustic and seismic wave propagation based on the most faithful 3D representation of the seabed sediments and underlying rocks. This project first focused on the 3D environment representation based on specific surveys and on two blasting experiments which consist in exploding bombs of different loads at two distinct environmental places. The in-situ measurements reveal several hundred circular figures with very specific characteristics which clearly differentiate them from other sedimentary, biological and geological figures encountered on the seabed. They are found within the whole studied area and their diameter is from 10 to 130 m. About 30 circles by kilometer square are observed without correlation with the depth which varies from 10 to 150m. These sedimentary structures indicate that they have been generated by the explosion of bombs, but at different periods. The oldest ones most probably result from bombs dropped in 1940 and 1944 during the landing of the Allied forces in the region of Toulon. These original anthropic sedimentary figures and their differences compared with other circular structures observed on the seabed are described. [ABSTRACT FROM AUTHOR]

The InSight lander will deliver geophysical instruments to Mars in 2018, including seismometers installed directly on the surface (Seismic Experiment for Interior Structure, SEIS). Routine operations will be split into two services, the Mars Structure Service (MSS) and Marsquake Service (MQS), which will be responsible, respectively, for defining the structure models and seismicity catalogs from the mission. The MSS will deliver a series of products before the landing, during the operations, and finally to the Planetary Data System (PDS) archive. Prior to the mission, we assembled a suite of a priori models of Mars, based on estimates of bulk composition and thermal profiles. Initial models during the mission will rely on modeling surface waves and impact-generated body waves independent of prior knowledge of structure. Later modeling will include simultaneous inversion of seismic observations for source and structural parameters. We use Bayesian inversion techniques to obtain robust probability distribution functions of interior structure parameters. Shallow structure will be characterized using the hammering of the heatflow probe mole, as well as measurements of surface wave ellipticity. Crustal scale structure will be constrained by measurements of receiver function and broadband Rayleigh wave ellipticity measurements. Core interacting body wave phases should be observable above modeled martian noise levels, allowing us to constrain deep structure. Normal modes of Mars should also be observable and can be used to estimate the globally averaged 1D structure, while combination with results from the InSight radio science mission and orbital observations will allow for constraint of deeper structure. [ABSTRACT FROM AUTHOR]

The InSight mission (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) has been collecting high-quality seismic data from Mars since February 2019, shortly after its landing. The Marsquake Service (MQS) is the team responsible for the prompt review of all seismic data recorded by the InSight's seismometer (SEIS), marsquake event detection, and curating seismicity catalogues. Until sol 1011 (end of September 2021), MQS have identified 951 marsquakes that we interpret to occur at regional and teleseismic distances, and 1062 very short duration events that are most likely generated by local thermal stresses nearby the SEIS package. Here, we summarize the seismic data collected until sol 1011, version 9 of the InSight seismicity catalogue. We focus on the significant seismicity that occurred after sol 478, the end date of version 3, the last catalogue described in a dedicated paper. In this new period, almost a full Martian year of new data has been collected, allowing us to observe seasonal variations in seismicity that are largely driven by strong changes in atmospheric noise that couples into the seismic signal. Further, the largest, closest and most distant events have been identified, and the number of fully located events has increased from 3 to 7. In addition to the new seismicity, we document improvements in the catalogue that include the adoption of InSight-calibrated Martian models and magnitude scales, the inclusion of additional seismic body-wave phases, and first focal mechanism solutions for three of the regional marsquakes at distances ∼30°. • The V9 catalogue includes 951 events, of which 486 are new since the previous report. • Multiple large marsquakes with M W Ma 4.0–4.2 were recorded. • Some new events are within 100 km of the lander and beyond the core shadow which were not seen before. • Four events are located close to the lander, which include chirps and are interpreted as meteorite impacts. • The catalogue also includes 1062 very local events that may be due to thermal stresses. [ABSTRACT FROM AUTHOR]

The existing global tomographic methods result in different models due to different parametrization, scale resolution and theoretical approach. To test how current imaging techniques are limited by approximations in theory and by the inadequacy of data quality and coverage, it is necessary to perform a global-scale benchmark to understand the resolving properties of each specific imaging algorithm. In the framework of the Seismic wave Propagation and Imaging in Complex media: a European network (SPICE) project, it was decided to perform a benchmark experiment of global inversion algorithms. First, a preliminary benchmark with a simple isotropic model is carried out to check the feasibility in terms of acquisition geometry and numerical accuracy. Then, to fully validate tomographic schemes with a challenging synthetic data set, we constructed one complex anisotropic global model, which is characterized by 21 elastic constants and includes 3-D heterogeneities in velocity, anisotropy (radial and azimuthal anisotropy), attenuation, density, as well as surface topography and bathymetry. The intermediate-period (>32 s), high fidelity anisotropic modelling was performed by using state-of-the-art anisotropic anelastic modelling code, that is, coupled spectral element method (CSEM), on modern massively parallel computing resources. The benchmark data set consists of 29 events and three-component seismograms are recorded by 256 stations. Because of the limitation of the available computing power, synthetic seismograms have a minimum period of 32 s and a length of 10 500 s. The inversion of the benchmark data set demonstrates several well-known problems of classical surface wave tomography, such as the importance of crustal correction to recover the shallow structures, the loss of resolution with depth, the smearing effect, both horizontal and vertical, the inaccuracy of amplitude of isotropic S-wave velocity variation, the difficulty of retrieving the magnitude of azimuthal anisotropy and so on. The synthetic data set can be used to validate and calibrate new processing methodologies and has been made available to the scientific community at the Institut de Physique du Globe de Paris (IPGP) website ( ). Any group wishing to test their tomographic algorithm is encouraged to download the synthetic data. [ABSTRACT FROM AUTHOR]

Abstract: The geodynamics of the mantle below Africa is not well understood and anisotropy tomography can provide new insight into the coupling between the African plate and the underlying mantle convection. In order to study the anisotropic structure of the upper mantle beneath Africa, we have measured phase velocities of 2900 Rayleigh and 1050 Love waves using the roller-coaster algorithm [Beucler, E., Stutzmann, E., Montagner, J.-P., 2003. Surface-wave higher mode phase velocity measurments, using a roller-coaster type algorithm. Geophys. J. Int. 155 (1), 289–307]. These phase velocities have been inverted to obtain a new tomographic model that gives access to isotropic SV-wave velocity perturbations, azimuthal and radial anisotropies. Isotropic SV-wave velocity maps have a lateral resolution of 500km. Anisotropy parameters have a lateral resolution of 1000km which is uniform over Africa for azimuthal anisotropy but decreases at the West and South of Africa for radial anisotropy. At shallow depth, azimuthal anisotropy varies over horizontal distances much smaller than the continent scale. At 280km depth, azimuthal anisotropy is roughly N-S, except in the Afar area, which might indicate differential motion between the African plate and the underlying mantle. The three cratons of West Africa, Congo and Kalahari are associated with fast velocities and transverse anisotropy that decrease very gradually down to 300km depth. On the other hand, we observe a significant change in the direction and amplitude of azimuthal anisotropy at about 180km depth, which could be the signature of the root of these cratons. The Tanzania craton is a shallower structure than the other African cratons and the slow velocities (−2%) observed on the maps at 180 and 280km depth could be the signature of hot material such as a plume head below the craton. This slow velocity anomaly extends toward the Afar and azimuthal anisotropy fast directions are N-S at 180km depth, indicating a possible interaction between the Tanzania small plume and the Afar. The Afar plume is associated with a very slow velocity anomaly (−6%) which extens below the Red sea, the Gulf of Aden and the Ethiopian rift at 80km depth. The Afar plume can be observed down to our deepest depth (300km) and is associated with radial anisotropy smaller than elsewhere in Africa, suggesting active upwelling. Azimuthal anisotropy directions change with increasing depth, being N-S below the Red sea and Gulf of Aden at 80km depth and E–W to NE–SW at 180km depth. The Afar plume is not connected with the smaller hotspots of Central Africa, which are associated either with shallow slow velocities for Mt Cameroon or with no particular velocity anomaly and N-S azimuthal anisotropy for the hotspots of Tibesti, Darfur and Hoggar. A shallow origin for these hotspots is in agreement with their normal 3He/4He ratio and with their location in a region that had been weakened by the rifting of West and Central Africa. [Copyright &y& Elsevier]

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]

The InSight mission landed on Mars on 11/26/2018. This is the first planetary mission deploying a complete geophysical observatory on another body than Earth after the Apollo Lunar Surface Experiments Package (ALSEP) deployed on the Moon during the Apollo program. It will provide the first ground truth constraints on interior structure of the planet. The Seismic Experiment for Interior Structure (SEIS) is one of the three primary scientific investigations, the two other ones being the Heat Flow and Physical Properties Package (HP3) and the Rotation and Interior Structure Experiment (RISE). SEIS is completed by the APSS experiment (InSight Auxiliary Payload Suite), one of which goal is to document the atmospheric source of seismic noise and signals. After a brief description of the SEIS experiment, we report the deployment process, including the evolution of the SEIS noise from on the deck measurements (with only SPs) toward on the ground (with both VBBs and SPs), without and finally with wind shield. We compare these noise levels to those obtained on Earth during tests, to those recorded on the Moon and to those predicted prior the landing. In all configurations, we identify the contribution of the lander noise and finally discuss what might remain in term of micro-seismic background, i.e. uncoherent seismic waves background.As proposed by several studies made prior the landing, atmospheric seismic signals on the ground are expected from turbulence in the planetary boundary layer or from dust devils, at both long period and short period. We expect also local time variation of the seismic noise as a consequence of weather activity as well as possible micro-seismic noise associated to trapped surface or body waves in the subsurface low velocity channel. We challenge these predictions with the data and discuss the events and spectrum identified with both the SEIS and APSS data. We finally compare them with modeling made with different subsurface structure. [ABSTRACT FROM AUTHOR]