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Marsquake recordings by NASA’s InSight seismometer often have low signal-to-noise ratios (SNR) owing to low marsquake amplitudes - only a handful of events are over M3.5 and epicentral distances are large, due to the single station being located in a seismically quiet region, and highly fluctuating atmospheric, spacecraft and instrumental noise signals.We have previously shown [1] how deep convolutional neural networks (CNN) can be used for 1) event detection - thereby producing an event catalogue consistent with the manually curated catalogue by the Marsquake Service (MQS) [2], and further extending it from 1297 to 2079 seismic events - as well as for 2) separating event and noise signals in time-frequency domain. Due to the low number of events readily-available for network training, we trained the CNN on synthetic event data combined with recorded InSight noise.Here, we construct a semi-synthetic data set (with real marsquake & noise data) to assess the denoising performance of the CNN w.r.t. to various evaluation metrics such as SNR, signal-distortion-ratio, cross-correlation, and peak amplitude of the recovered event waveforms, and compare modifications of the CNN architecture and the training data set.For a large number of identified events [1,2] no distance estimates are available (or only with high uncertainty), and for all but a small subset the back azimuth is unclear, as the relatively high background noise often obscures this information in the waveforms. We explore how the denoised waveforms can support the phase picking and polarisation analysis of marsquakes, and with that their localisation, as well as their general characterisation. References:[1] Dahmen et al. (2022), doi: 10.1029/2022JE007503[2] Ceylan et al. (2022), doi: 10.1016/j.pepi.2022.106943

Aeolian activity, the movement of sand and dust by the wind, is common on Earth and has been observed on other planets [1]. Under the current climatic conditions on Mars, aeolian activity is the primary process of surface modification driven by winds, dust storms and wind vortices. Landed and orbiting cameras show that widespread aeolian activity occurs despite low measured and modelled winds, challenging Earth-based theories [2, 3]. Dust particles enter into long-term suspension forming global dust storms which drastically alter the Martian atmospheric dynamics and present hazards to robotic and human missions.Several models have been proposed on the long-standing conundrum of sediment transport on Mars, however, none of these have been verified on the planet. The outstanding question of what wind shear velocities mobilize sediments on Mars has remained elusive despite multiple spacecrafts carrying wind sensors and studying aeolian activity on finer spatial and temporal scales than can be achieved in orbit. Quantitative examination of aeolian activity under natural Martian surface conditions is imperative in validating transport models.The InSight lander has provided a unique opportunity for monitoring simultaneous coverage of aeolian activity on Mars by combining, for the first time, imaging with atmospheric, seismic and magnetic measurements. Previous studies spanned over just half of the first Martian year, from the end of northern winter to midsummer, and observed minor aeolian activity limited to sporadic grain motion and dust devil tracks [4, 5].In this study, we extend observations of aeolian activity for two Martian years, allowing us to infer the seasonal evolution at the landing site. We report a series of remarkable daytime vortex-induced events with pressure excursions up to 10 Pa, including an investigation of the burst in daytime vortices and emergence of nighttime vortices in northern autumn. Despite our observations reinforcing the quiescent aeolian surface environment at InSight, we observe further evidence and constrain timings of surface track formation, saltation, dust lifting and surface creep of coarser particles both on the surface of Mars and lander elements. Such an investigation was previously impossible due to power constraints allowing only intermittent meteorological measurements in the second year and wind-sensor saturation from energetic close vortex encounters that cause surface changes. Here, we derive estimates of vortex-induced peak wind speeds responsible for grain motion based on strong correlations from the excitation of high-frequency lander resonances sensitive to wind forcing measured continuously by the seismometers [6]. This wealth of data allows us to obtain a unique catalogue of complete wind-induced surface activity at InSight over two Martian years. Our findings provide an insight into the long-standing paradox of aeolian transportation on Mars by quantifying the environmental variables responsible for sand motion which help constrain current threshold and transport models.[1] Hayes (2018) Sci. [2] Kok et al. (2012) RPP [3] Newman et al. (2022) Auth. [4] Charalambous et al. (2021) JGR 126(6) e2020JE006538 [5] Baker et al., (2021) JGR [6] Charalambous et al. (2021) JGR 126(4) e2020JE006514.

We report confirmed impact sources for two seismic events on Mars detected by the NASA InSight mission. These events have been positively associated with fresh impact craters identified from orbital images, which match predicted locations and sizes, and have formation time constraints consistent with the seismic event dates. They are both of the Very High Frequency family of seismic events and display impact-acoustic chirps. This brings the total number of confirmed martian impact-related seismic events to eight thus far. All seismic events with chirp signals have now been confirmed as having been caused by impact cratering events. This includes all seismic activity within 100 km of the lander, and two out of the four events with source locations between 100-300 km distance.

We present the first observations of seismic waves propagating through the core of Mars. These observations, made using seismic data collected by the InSight geophysical mission, have allowed us to construct the first seismically constrained models for the elastic properties of Mars' core. We observe core-transiting seismic phase SKS from two farside seismic events detected on Mars and measure the travel times of SKS relative to mantle traversing body waves. SKS travels through the core as a compressional wave, providing information about bulk modulus and density. We perform probabilistic inversions using the core-sensitive relative travel times together with gross geophysical data and travel times from other, more proximal, seismic events to seek the equation of state parameters that best describe the liquid iron-alloy core. Our inversions provide constraints on the velocities in Mars' core and are used to develop the first seismically based estimates of its composition. We show that models informed by our SKS data favor a somewhat smaller (median core radius = 1,780 to 1,810 km) and denser (core density = 6.2 to 6.3 g/cm3) core compared to previous estimates, with a P-wave velocity of 4.9 to 5.0 km/s at the core-mantle boundary, with the composition and structure of the mantle as a dominant source of uncertainty. We infer from our models that Mars' core contains a median of 20 to 22 wt% light alloying elements when we consider sulfur, oxygen, carbon, and hydrogen. These data can be used to inform models of planetary accretion, composition, and evolution., Proceedings of the National Academy of Sciences of the United States of America, 120 (18), ISSN:0027-8424, ISSN:1091-6490

After ~4 years of deployment on the martian surface monitoring the planet’s ground motion, the InSight seismometer is now retired. Here, we review the procedures and methods the Marsquake Service (MQS) used to curate the seismic event catalog and describe the content of the catalog. The marsquake catalogue is different from normal catalogues on Earth as it aims to provide the authoritative catalog for the mission, covering the entire planet, using only a single station. As of January 1st, 2023, the MQS catalog contains 1319 seismic events of which 6 are known meteorite impacts. We have also identified 1383 superhigh frequency events that are interpreted as thermal cracking nearby the InSight lander. Late in the project large distant events occurred that allowed MQS to detect surface waves. Multiple events have been associated as impacts using orbital imaging, confirming the MQS single station location procedures. All of these new seismic phases have contributed to advance our understanding of the internal structure of Mars. The marsquake S1222a, the largest event recorded during the mission (MW 4.7) occurred in March 2022 and is also documented in our latest MQS catalog, V13, with many associated seismic phases including both Rayleigh and Love waves, their first-order overtones, and multi-orbiting surface waves that have not been identified in other marsquake records from our previous catalogues. The InSight mission is now closed but the MQS operation continues to analyze the ~4 years of seismic recordings on Mars and a final catalog, including event-specific products such as filter banks, and spectra, is in preparation. This final catalog will inform capabilities and field strategies in geophysical explorations for future martian science missions.

The InSight mission collected an astounding seismic dataset from Mars during more than four years (1450 sols) of operation until it was retired on 21 December 2022.The Marsquake Service MQS detected more than 1300 events of seismic origins. Two of these events (S1000a and S1094b) were later confirmed as distant impacts (Figure 1), with magnitudes of MWMa=4.0 and 4.2 and crater diameters of 130 and 150 m, respectively. Finally, the largest marsquake (S1222a, MWMa=4.6) that occurred during InSight's lifetime was recorded on May 4, 2022.Here, we present the current understanding of the Martian seismicity and the different types of events we observed on Mars, based on the data collected over the whole mission.Low-frequency (LF) and broadband (BB)The LF family of events include energy predominantly below 1 Hz. They are similar to teleseismic events observed on Earth, and clear P and S waves are often identified. The hypocenter is known for about half of the recorded LF-BB events, owing to the difficulty of determining back-azimuth and in some cases also distance for the smaller events. The following elements are now understood:Seismicity appears to be located only in few spots around Mars (Figure 2) and no tectonic events were located within 25° from the InSight station. A large number of LF-BB events are located 26–30° from the station, interpreted to be associated with the active dynamics of the volcanic Cerberus Fossae area. A group of events show only a weak S-wave energy and are aligned using the P-wave and length of its coda to around 46°. Their tectonic origin is yet unknown. A few events are located around 60° with relatively emergent P- and S-wave energy. Two large events (S0976a and S1000a) lie beyond the core shadow and have PP and SS phases; S0976a in the Valles Marineris region 146° away from InSight, and S1000a as the result of a meteoritic impact. A number of events of uncertain location are clustered in the same distance, around 100-120° distance. LF events have the largest magnitudes with S1222a reaching MWMa=4.6 and a few others at or above MWMa=3.5. High-frequency (HF) The HF family of events are predominantly at and above the 2.4 Hz, local subsurface resonance. The HF events have magnitudes below MWMa 2.5 and originate from a distance range of 25–30°, likely a single area in the central Cerberus Fossae region, as very shallow events associated to active volcanic dykes. Very high frequency (VF):A small number of HF events are characterized by higher frequency content, up to 20–30 Hz with a notable amplification on the horizontal components at very high frequency, and are termed VF events. The amplification is plausibly explained by the local subsurface structure. These events are observed only close to the lander. Remote imaging of recent craters and the presence of a distinctive acoustic signal confirmed that the closest events were produced by meteoric impacts. Investigations are being conducted to understand if other VF events can be confirmed as impacts, too.

NASA's InSight lander successfully touched down on Mars in November 2018, and, for the first time, a seismometer was deployed on the surface of the planet. The seismic recordings reveal diurnal and seasonal changes of the broadband noise level that are consistent with variations of the local atmospheric conditions. The seismic data include a variety of spectral peaks, which are interpreted as wind‐excited, mechanical resonances of the lander, resonances of the subsurface, or artifacts produced in the measurement system. Understanding the origin of these signals is critical for the detection and characterization of marsquakes as well as for studies investigating the ambient noise. We identify the major spectral peaks up to 9 Hz, corresponding to the frequency range the most relevant to observed marsquakes. We track the variations in frequency, amplitude, and polarization of these peaks over the duration of the mission so far. The majority of these peaks can readily be classified as measurement artifacts or lander resonances (lander modes), of which the latter have a temperature‐dependent peak frequency and a wind‐sensitive amplitude. Of particular interest is a prominent resonance at 2.4 Hz, which is used to discriminate between seismic events and local noise and is possibly produced by a subsurface structure. In contrast to the lander modes, the 2.4 Hz resonance has distinctly different features: (1) a broad and stable spectral shape, slightly shifted on each component; (2) predominantly vertical energy; (3) temperature‐independent peak frequency; (4) comparatively weak amplification by local winds, though there is a slow change in the diurnal and seasonal amplitude; and (5) excitation during all seismic events that excite this frequency band. Based on these observations, we suggest that the 2.4 Hz resonance is the only mode below 9 Hz that could be related to a local ground structure., Bulletin of the Seismological Society of America, 111 (6), ISSN:0037-1106, ISSN:1943-3573

PurposeThis paper aims to study and analyse thematic literature on sustainability and its challenges in destinations that highly depend on tourism. The aim of the paper is to focus on the opportunities and challenges for the sustainability of the tourist industry in Cyprus. The criteria for tourism sustainability are identified in UNESCO publications and are categorized as environmental, social and economic/financial. The paper examines the theory as well as the empirical applications regarding these criteria for the island of Cyprus, emphasizing the steps which have been taken by the government as well as other organizations towards maintaining industry sustainability. Opportunities that arise as a result of European Commission-funded programmes are also mentioned. Identification of the challenges is also very significant as they hinder sustainability practices. The paper tackles this issue and provides proposals as to the possible solutions to these challenges.Design/methodology/approachThe paper provides a review of scientific and theoretical research studies by various authors on the concept and principles of sustainable tourism, the effects of tourism on society and the sustainable tourism strategy.FindingsThe basic principles of sustainable tourism development apply to all destinations, including Cyprus. The development of tourism is associated only with the observance of the principles of sustainable tourism development, which takes the form of balanced environmental and economic development and involves the observance of public interests.Originality/valueThe paper presents a viewpoint on sustainable tourism and the principles and development thereof.

Constraining the thermal and compositional state of the mantle is crucial for deciphering the formation and evolution of Mars. Mineral physics predicts that Mars' deep mantle is demarcated by a seismic discontinuity arising from the pressure-induced phase transformation of the mineral olivine to its higher-pressure polymorphs, making the depth of this boundary sensitive to both mantle temperature and composition. Here, we report on the seismic detection of a midmantle discontinuity using the data collected by NASA's InSight Mission to Mars that matches the expected depth and sharpness of the postolivine transition. In five teleseismic events, we observed triplicated P and S waves and constrained the depth of this discontinuity to be 1,006 [Formula: see text] 40 km by modeling the triplicated waveforms. From this depth range, we infer a mantle potential temperature of 1,605 [Formula: see text] 100 K, a result consistent with a crust that is 10 to 15 times more enriched in heat-producing elements than the underlying mantle. Our waveform fits to the data indicate a broad gradient across the boundary, implying that the Martian mantle is more enriched in iron compared to Earth. Through modeling of thermochemical evolution of Mars, we observe that only two out of the five proposed composition models are compatible with the observed boundary depth. Our geodynamic simulations suggest that the Martian mantle was relatively cold 4.5 Gyr ago (1,720 to 1,860 K) and are consistent with a present-day surface heat flow of 21 to 24 mW/m2., Proceedings of the National Academy of Sciences of the United States of America, 119 (42), ISSN:0027-8424, ISSN:1091-6490

For over three Earth years, NASA’s InSight mission has returned data from the Seismic Experiment for Interior Structure (SEIS) on Mars with over 1300 recorded marsquakes (Horleston et al., this issue), leading to numerous breakthroughs in determining the planet's structure (Khan et al., 2021; Stähler et al., 2021; Knapmeyer-Endrun et al., 2021). However, a large number of detected marsquakes are contaminated by SEIS’s complex interaction with the Martian atmosphere which injects noise and couples into the seismic signal. Identification of surface waves, polarisation analysis and clear body-wave arrivals is therefore often inhibited by this strong atmospheric noise. Despite numerous identifications, only 12 events have so far been fully located. Detection and analysis of the seismic component thus requires separation from such aseismic signal sources. Here we present a novel denoising model which exploits the strong correlation between the ground motion and the atmospheric conditions recorded at InSight. The approach exploits linearities in the noise injected by the atmosphere by using weather data measured by the lander, or in the absence of such data due to power constraints, the excitation of wind-sensitive lander modes that have been proven an effective atmospheric proxy in estimating this injection on Mars (Charalambous et al., 2021; Clinton et al., 2021; Dahmen et al., 2021). The output results in “demodulation”, i.e., the cancellation of any environmental noise and the effective isolation of the seismic signal power in time-frequency space. Our denoising approach is thus able to remove and decouple the environmental noise from the seismic signal to reveal features in the seismic event waveform that were previously hidden in the noise. Using the proposed denoising technique, we investigate all marsquake events above magnitude 3 to search for surface waves not identifiable with pre-existing methods. To correctly identify and associate these dispersive wave packets as Rayleigh and Love waves, we examine the characteristics of each through frequency-dependent polarisation analysis. The residual power from the denoised signal allows an accurate examination of the partitioning of energy between the horizontal and vertical components (H/V ratio) of the event. This energy isolation in turn informs an H/V-weighted polarisation analysis which enhances the characteristics of body and surface waves. This approach effectively cancels out the contribution of other polarised signals from the environment, enhancing the characteristics in the signal of interest. The residuals thus not only allow us to correctly identify surface waves, but also locate events which could not previously be located by refining back-azimuths and distances through clear P- and S-wave arrivals. Using these results, we investigate the lateral variation in the crustal properties with events that are located close to an equatorial transect of Mars, including both major- and minor-arc detections. Events not on the transect further allow us to populate a map of lateral variations in thickness of the crust revealing geographical differences in the crustal structure, but also constraining the average thickness of the crust and the range of allowable crustal densities. This places additional constraints on the seismic velocities of the crust and lithosphere. Finally, with demodulation we further explore the identification and validation of multi-orbit Rayleigh waves and second-arriving Love wave packets from InSight’s largest marsquake recorded so far at a moment magnitude of 4.7 (S1222a), providing further constraints to the model. References Charalambous, C., Stott, A. E., Pike, W. T., ... & Banerdt, W. B. (2021). A Comodulation Analysis of Atmospheric Energy Injection Into the Ground Motion at InSight, Mars. Journal of Geophysical Research: Planets, 126(4). Clinton, J. F., Ceylan, S., van Driel, ... & Stott, A. E. (2021). The Marsquake catalogue from InSight, sols 0–478. Physics of the Earth and Planetary Interiors, 310, 106595. Dahmen, N. L., Zenhäusern, G., Clinton, ... & Banerdt, W. B. (2021). Resonances and lander modes observed by insight on Mars (1–9 Hz). Bulletin of the Seismological Society of America, 111(6), 2924-2950. Horleston, A., Clinton, J., Ceylan, S., … Banerdt, W. B. The seismicity of Mars as recorded by InSight’s Marsquake Service, this issue Khan, A., Ceylan, S., van Driel, M., ... & Banerdt, W. B. (2021). Upper mantle structure of Mars from InSight seismic data. Science, 373(6553), 434-438. Stähler, S., Khan, A., Banerdt, W. B., ... & Smrekar, S. (2021). Seismic detection of the martian core. Science, 373(6553), 443-448. Knapmeyer-Endrun, B., Panning, M. P., Bissig, F., ... & Banerdt, W. B. (2021). Thickness and structure of the martian crust from InSight seismic data. Science, 373(6553), 438-443.

International audience; Meteoroid impacts shape planetary surfaces by forming new craters and alter atmospheric composition. During atmospheric entry and impact on the ground, meteoroids excite transient acoustic and seismic waves. However, new crater formation and the associated impact-induced mechanical waves have yet to be observed jointly beyond Earth. Here we report observations of seismic and acoustic waves from the NASA InSight lander’s seismometer that we link to four meteoroid impact events on Mars observed in spacecraft imagery. We analysed arrival times and polarization of seismic and acoustic waves to estimate impact locations, which were subsequently confirmed by orbital imaging of the associated craters. Crater dimensions and estimates of meteoroid trajectories are consistent with waveform modelling of the recorded seismograms. With identified seismic sources, the seismic waves can be used to constrain the structure of the Martian interior, corroborating previous crustal structure models, and constrain scaling relationships between the distance and amplitude of impact-generated seismic waves on Mars, supporting a link between the seismic moment of impacts and the vertical impactor momentum. Our findings demonstrate the capability of planetary seismology to identify impact-generated seismic sources and constrain both impact processes and planetary interiors.

The hybrid impression technique consists of an initial alginate impression that provides a preoperative cast upon which a diagnostic wax‐up and a silicone index are made. The wax‐up is digitized; thus, the final altered digital impression is limited to absolute minimum time, effort and ensures comfort for the patient., Alginate initial impression provides a preoperative cast upon which a previous prosthesis can be attached in lieu of a diagnostic wax‐up. A silicone index or surgical guide can be made in one appointment in the dental office saving time and effort.

On the 1222nd sol of the InSight mission (or May the Fourth of 2022), a seismic event was detected that turned out to be the largest marsquake recorded so far. At a moment magnitude of 4.7, event S1222a released as much seismic moment as all seismic events previously catalogued by InSight together, and greatly surpasses the second largest event, S0976a.The frequency of occurrence of earthquakes follows a power law with an exponent (the b value) close to 1 over a wide range of magnitudes. The class of Low Frequency marsquakes, to which S1222a belongs, shows a similar behaviour. At low magnitudes, the slope of the cumulative distribution suggests that the InSight marsquake catalog for Low Frequency events is representative for events with moment magnitude exceeding 3 (Figure 1). Up to and including the occurrence of event S0976a one could however guess that events larger than magnitude approx. 3.6 might be less frequent than predicted by this power law. Event S1222a mends this apparent decrease, and the b value derived from all events is 1 within the formal uncertainty. Hence the resulting distribution follows a power law for events exceeding magnitude 3.Figure 1 Size frequency distribution of Low Frequency and Broadband events. Red: status before occurrence of S1222a, blue: afterwards. The dashed lines represent the Maximum Likelihood solutions for fitting a Power Law distribution, with b-values as indicated in the legend.Since S0976a occurred at an epicentral distance of about 140° (Horleston et al., 2022) at night time(02:26 LMST), but was recorded with amplitudes high enough to be visible during typical day time noise, we can infer that the catalog is complete for events the size of S0976a or larger. Since the slope of the distribution appears to be stable over the entire magnitude range from 3 up to that of S1222a, we conclude that the catalogue of Low Frequency events is not only representative, but complete for events larger than 3.The magnitude of S1222a is slightly to the right of the value predicted by the power law, but, compared to other deviations, not excessively so. Also, the distribution does not show an indication of increasing slope any more. With about 30 events of magnitude 3 during the 3.3 years of InSight observations so far, this suggests that events larger than S1222a can be expected with respective recurrence rates: A magnitude 5 event appears likely about once in 11 years, i.e. on a decadal scale.We use the approach of Knapmeyer et al. (2018) to estimate the seismic moment rate of Mars, and also the corner magnitude above which the size-frequency distribution becomes much steeper and events larger than the corner magnitude extremely unlikely (our analysis uses the Tapered Gutenberg-Richter distribution with an exponential roll-off above the corner frequency). The simple idea of Knapmeyer et al. (2018) was that, since a few large events release most of the seismic moment, the moment of the largest event ever observed, scaled with the duration covered by the catalog and a factor depending on b value and corner moment, provides a good estimation of the moment rate. Including not only the one largest, but the n largest events (with n between 1 and 10 or so) provides an even better estimation. In the 2018 study we have shown that the approach yields a surprisingly good estimation of the Earth's moment rate after a few months of registration, rather than after the many decades necessary to witness a magnitude 9 event.We employ here an estimation based on the 5 largest events in the catalog. Knapmeyer et al. (2018) have shown that this low number may already provide a reasonable rate estimate. At the same time we attempt to avoid using events too small to be globally detectable. Future analyses will show if the use of 5 events is actually the best choice. The inclusion of event S1222a shifts the estimated moment rate slightly upwards, as well as the estimated corner moment. Figure 2 shows that both parameters are slightly below those of the WeakMany model of Knapmeyer et al., (2006). Compared to the catalog from before its occurrence, the parameter modifications due to S1222a are hardly significant (and not shown here). At least as important is the reduction of the uncertainty region in the moment-rate / corner-moment parameter space. We cannot yet exclude that the moment rate of Mars is as low as that of the Moon, but if it were, it would be rather unlikely to observe the event sequence that InSight observed.Figure 2 Estimation of Moment Rate and Corner Moment. For each Pixel, 10000 synthetic catalogs were evaluated to compare their parameters with the five largest events from the InSight catalog (KS5 estimation). Colour indicates the probability that the five largest events drawn from a tapered Gutenberg Richter distribution in 3.3 years reproduce the KS5 estimation obtained from the observed events, to within an 80 % interdecile around the median. The vertical line indicates the moment rate for the Moon (observed, from Shallow Moonquakes), markers indicate the WeakMany and Medium models of Knapmeyer et al. (2006). The moment rate of the Earth corresponds to an equivalent magnitude of about 8.5 (Knapmeyer et al., 2018). Horizontal lines indicate the magnitude of the largest event and its uncertainty. The maximum of the distribution is marked by a small white circle. ReferencesHorleston, A. C., et al. (2022). The Far Side of Mars: Two Distant Marsquakes Detected by InSight, The Seismic Record. 2(2), 88–99, doi: 10.1785/0320220007Knapmeyer, M., Oberst, J., Hauber, E., Wählisch, M., Deuchler, C., Wagner, R. (2006). Working models for spatial distribution and level of Mars' seismicity. Journal of Geophysical Research, vol. 111, E11006, doi:10.1029/2006JE002708Knapmeyer, M., et al. (2018). Estimation of the Seismic Moment Rate from an Incomplete Seismicity Catalog, in the Context of the InSight Mission to Mars, Bull. Seis. Soc. Am., vol. 109, No. 3, 1125-1147, doi: 10.1785/0120180258Taylor et al., (2013). Estimates of seismic activity on the Cerberus Fossae region of Mars, Journal of Geophysical Research, vol. 118, 2570-2581, doi:10.1002/2013JE004469

NASA's InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) mission has operated a sophisticated suite of seismology and geophysics instruments on the surface of Mars since its arrival in 2018. On 18 February 2021, we attempted to detect the seismic and acoustic waves produced by the entry, descent and landing of the Perseverance rover using the sensors onboard the InSight lander. Similar observations have been made on Earth using data from both crewed(1,2) and uncrewed(3,4) spacecraft, and on the Moon during the Apollo eras(5), but never before on Mars or another planet. This was the only seismic event to occur on Mars since InSight began operations that had an a priori known and independently constrained timing and location. It therefore had the potential to be used as a calibration for other marsquakes recorded by InSight. Here we report that no signal from Perseverance's entry, descent and landing is identifiable in the InSight data. Nonetheless, measurements made during the landing window enable us to place constraints on the distance-amplitude relationships used to predict the amplitude of seismic waves produced by planetary impacts and place in situ constraints on Martian impact seismic efficiency (the fraction of the impactor kinetic energy converted into seismic energy)., Nature Astronomy, 6 (1), ISSN:2397-3366

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°.

Rocks around the InSight lander were measured in lander orthoimages of the near field (

In preparation for the National Aeronautics and Space Administration Interior exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) Discovery Program mission, Böse et al. (2018) calibrated magnitude scales for marsquakes that incorporated prelaunch knowledge of Mars’ interior structure and the expected ambient and instrumental noise. Now, using data collected during the first two years after the successful deployment of the InSight very-broadband seismometer on the Martian surface, we revise these relations to account for the seismic and noise characteristics observed on Mars. The data collected so far (until 12 October 2020) include 485 seismic event detections and suggest that (1) marsquakes are characterized by energy between ∼0.1 and 10 Hz; (2) whereas first arriving P- and S-wave phases are regularly identified and assigned, both surface waves and secondary phase arrivals are extremely challenging to identify; (3) the majority of identified events include a strong excitation of an unexpected 2.4 Hz ground resonance; and (4) so-called high-frequency (HF) events exist that are visible mainly as guided Pg/Sg wave trains. In view of these observations, we update our scaling relations for the spectral and body-wave magnitudes, Mw,specMa, mbMa, and mbSMa, and introduce a new magnitude scale, M2.4Ma, for HF events. We use these scales to determine that the magnitudes of events in the current InSight version 5 catalog range between 1.1 and 3.7, with event-specific uncertainties σM ranging from 0.2 to 0.4. Because of the currently unclear interpretation of HF events, magnitude estimates for these events primarily serve as a relative comparison.

Orbital and surface observations can shed light on the internal structure of Mars. NASA’s InSight mission allows mapping the shallow subsurface of Elysium Planitia using seismic data. In this work, we apply a classical seismological technique of inverting Rayleigh wave ellipticity curves extracted from ambient seismic vibrations to resolve, for the first time on Mars, the shallow subsurface to around 200 m depth. While our seismic velocity model is largely consistent with the expected layered subsurface consisting of a thin regolith layer above stacks of lava flows, we find a seismic low-velocity zone at about 30 to 75 m depth that we interpret as a sedimentary layer sandwiched somewhere within the underlying Hesperian and Amazonian aged basalt layers. A prominent amplitude peak observed in the seismic data at 2.4 Hz is interpreted as an Airy phase related to surface wave energy trapped in this local low-velocity channel., Nature Communications, 12 (1), ISSN:2041-1723

The National Aeronautics and Space Administration InSight mission has deployed the seismic experiment, SEIS, on the surface of Mars, and has recorded a variety of signals including marsquakes and dust devils. This work presents results on the tilt and local noise sources, which provide context to aid interpretation of the observed signals and allow an examination of the near-surface properties. Our analysis uses data recorded by the short-period sensors on the deck, throughout deployment and in the final configuration. We use thermal decorrelation to provide an estimate of the sol-to-sol tilt. This tilt is examined across deployment and over a Martian year. After each modification to the site, the tilt is seen to stabilize over 3–20 sols depending on the action, and the total change in tilt is

Clues to a planet’s geologic history are contained in its interior structure, particularly its core. We detected reflections of seismic waves from the core-mantle boundary of Mars using InSight seismic data and inverted these together with geodetic data to constrain the radius of the liquid metal core to 1830 ± 40 kilometers. The large core implies a martian mantle mineralogically similar to the terrestrial upper mantle and transition zone but differing from Earth by not having a bridgmanite-dominated lower mantle. We inferred a mean core density of 5.7 to 6.3 grams per cubic centimeter, which requires a substantial complement of light elements dissolved in the iron-nickel core. The seismic core shadow as seen from InSight’s location covers half the surface of Mars, including the majority of potentially active regions—e.g., Tharsis—possibly limiting the number of detectable marsquakes., Science, 373 (6553), ISSN:0036-8075, ISSN:1095-9203

International audience; We report the aeolian changes observed in situ by NASA's InSight lander during the first 400 sols of operations: Granule creep, saltation, dust removal, and the formation of dark surface tracks. Aeolian changes are infrequent and sporadic. However, on sols, when they do occur, they consistently appear between noon to 3 p.m., and are associated with the passage of convective vortices during periods of high vortex activity. Aeolian changes are more frequent at elevated locations, such as the top surfaces of rocks and lander footpads. InSight observed these changes using, for the first time, simultaneous insitu and orbital imaging and high-frequency meteorological, seismological, and magnetic measurements. Seismometer measurements of ground acceleration constrain the timing and trajectory of convective vortex encounters, linking surface changes to source vortices. Magnetometer measurements show perturbations in magnetic field strength during the passage of convective vortices consistent with chargedparticle motion. Detachment of sand-scale particles occurs when high background winds and vortexinduced turbulence provide a peak surface friction wind speed above the classic saltation fluid threshold. However, detachment of dust-and granule-scale particles also occurred when the surface friction wind speed remained below this threshold. This may be explained by local enhancement of the surface roughness and other effects described here and further studied in Part 2 (Baker et al., 2021). The lack of saltation and bright dust-coated surfaces at the InSight landing site implies surface stability and the onset of particle motion may be suppressed by dust "cushioning." This differentiates the InSight landing site from other areas on Mars that exhibit more aeolian activity. Plain Language Summary Aeolian activity, the movement of dust and sand by the wind, is common on Earth and has been observed on other planets, including Mars. A new Mars lander, InSight, has for the first time monitored aeolian changes by combining imaging with weather, seismic and CHARALAMBOUS ET AL.

International audience; 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.

Seismic noise recorded at the surface of Mars has been monitored since February 2019, using the InSight seismometers.This noise can reach -200 dB and is 500 times lower than on Earth at night and it increases of 30 dB during the day. We analyze its polarization as a function of time and frequency in the band 0.03-1Hz. We use the degree of polarization to extract signals with stable polarization independent of their amplitude and type of polarization. We detect polarized signals at all frequencies and all times. Glitches correspond to linear polarized signals which are more abundant during the night. For signals with elliptical polarization, the ellipse is in the horizontal plane below 0.3 Hz (LF). Above 0.3 Hz (HF) and except in the evening, the ellipse is in the vertical plane and the major axis is tilted. While polarization azimuths are different in the two frequency bands, they both vary as a function of local hour and season. They are also correlated with wind direction, particularly during the daytime.We investigate possible aseismic and seismic origins of the polarized signals. Lander or tether noise can be discarded. Pressure fluctuations transported by wind may explain part of the HF polarization but not the tilt of the ellipse. This tilt can be obtained if the source is an acoustic emission coming from high altitude at critical angle. Finally, in the evening when the wind is low, the polarized signals may correspond to the seismic wavefield of the Mars background noise.

The NASA InSight lander is a geophysical and meteorological observatory operating on Mars for over a Martian year/two Earth years. Continuous records of seismic, pressure, wind and temperature data over this period have led to significant breakthroughs in determining the planet's structure and climate. With such a wealth of data now received, machine learning offers a nascent tool to extract further information. The seismic data is extremely correlated to the atmospheric conditions. Discerning the coupling between the atmosphere and ground motion is of significant interest and this work aims to predict the ground motion generated by wind and pressure forcing using machine learning techniques. From this prediction we can untangle the various contributions to ground motion, determine atmospheric/ground properties, analyse/discriminate marsquakes and potentially decorrelate waveforms to remove the atmospheric contribution. While a physical model for this atmospheric forcing is desirable, machine learning approaches the problem from an alternative view point where mathematical and algorithmic tools add the necessary complexity for fitting the data. In this way, we may be able to capture detailed variation and inform further modelling efforts.We will detail the initial application of machine learning for predicting the ground motion from the atmospheric data inputs of wind speed, wind direction, pressure and temperature. First though, we will describe the issues that need to be tackled to obtain a good prediction using the InSight data. To illustrate some of some of these problems, consider that glitches are known to occur in the seismic data. They offer a way to detect overfitting as they should not in general be predicted from atmospheric forcing. However, a subset of the glitches are correlated to temperature on top of the fact they are only visible during quiet enough periods, as are marsquakes. Therefore, they are not a normally distributed source of noise or uncorrelated from the input atmospheric data, breaking typical assumptions used for regression. A similar issue is presented by the changing weather conditions throughout a Martian sol, where the time series distribution varies. As a result, prior information on the instrumentation and data qualities is essential for applying the machine learning methods and interpretation of the results.We demonstrate the specifics of the InSight data with respect to 1) how a curve fitting problem can be constructed, 2) the necessary degrees of freedom of the problem, 3) consideration of non-stationary/heteroscedastic errors and 4) the optimisation and machine learning method applied. Current results will be presented from the implementation of random forests and gaussian processes. These results demonstrate a good performance so far for capturing the global variation and we will offer perspectives on how these results can be used and improved.

On the first hundreds of sols in which the InSight lander operated on the surface of Mars, its instrumentation has proven to be particularly suitable to unveil and understand atmospheric variability at all temporal scales, from the synoptic scale (baroclinic waves) to the sub-hour scale (gravity waves, bores) down to the turbulent scale (vortices, gusts, infrasounds). Recently, the InSight lander achieved a complete Martian year of observations of the atmosphere of Mars -- allowing for the seasonal variability of the Martian atmosphere and its phenomena at all scales to be monitored almost continuously, including during several large dust storms episodes. In this presentation, based on this Martian year of InSight observations, we will review the annual CO2 sublimation / condensation cycle, the variability of large-scale meteorology, the statistics of a year of wind observations -- and insightful comparisons with global climate models, the strong seasonal variability of gravity wave and turbulent activity, including a burst of activity of convective vortices in Mars' southern summer. We will also discuss how the atmosphere influences seismic and magnetic signals captured by InSight -- and the search for Martian infrasound.

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International audience; A catalog of convective vortex encounters recorded by InSight on the Martian surface is presented, through Sol 390 of the mission. The catalog summarizes key meteorological parameters such as wind speed and direction before the event, peak wind, the duration and magnitude of the pressure excursion, temperatures and solar array data where present. Additional seismic parameters are also provided on seismometer-detected ground acceleration. The catalog is intended as a resource for vortex population studies, and as an index for examining these meteorological events in detail and to assess possible geophysical (seismic or magnetic) signatures. Whereas it is difficult to evaluate 'anecdotal' results in small surveys, the large number of events (853 with a pressure drop exceeding 0.8 Pa) in this work permits robust statistical evaluation. For example, it is found that three times as many pressure profiles have slower onsets than decays than vice versa, indicating an asymmetry in the surface pressure field due to the tilted advection of the vortex by ambient wind. A vortex area fraction of 0.07% during the most active six hours of the day is deduced.

Seismic noise recorded at the surface of Mars has been monitored since February 2019, using the InSight seismometers. This noise can reach -200 dB. It is 500 times lower than on Earth at night and it increases of 30 dB during the day. We analyze its polarization as a function of time and frequency in the band 0.03-1 Hz. We use the degree of polarization to extract signals with stable polarization independent of their amplitude and type of polarization. We detect polarized signals at all frequencies and all times. Glitches correspond to linear polarized signals which are more abundant during the night. For signals with elliptical polarization, the ellipse is in the horizontal plane below 0.3 Hz. In the 0.3-1Hz high frequency band (HF) and except in the evening, the ellipse is in the vertical plane and the major axis is tilted. While polarization azimuths are different in the two frequency bands, they both vary as a function of local hour and season. They are also correlated with wind direction, particularly during the daytime. We investigate possible aseismic and seismic origins of the polarized signals. Lander or tether noise can be discarded. Pressure fluctuations transported by wind may explain part of the HF polarization but not the tilt of the ellipse. This tilt can be obtained if the source is an acoustic emission coming from high altitude at critical angle. Finally, in the evening when the wind is low, the measured polarized signals may correspond to the seismic wavefield of the Mars background noise. Plain Language Summary Seismic noise at the surface of Mars was unknown until the first measurements by the seismometers from the InSight mission in January 2019. On Earth, the microseismic noise (0.05-1 Hz) is composed dominantly of surface waves generated by the numerous sources related to ocean wave activities. On Mars, because there is no ocean, seismic noise is down to 500 times lower than on Earth reaching -200 dB in acceleration at night. In order to determine the nature of the Mars noise, we analyze its polarization with a statistical method and show that it is different to that on Earth. In the low frequency band 0.03-0.3 Hz, we detect signals with elliptical polarization in the horizontal plane. In the high frequency band 0.3-1Hz (HF), signals have elliptical polarization in the vertical plane. The polarization ellipse azimuth gives the direction toward the source. On Mars, these azimuths are varying as a function of local hour and season and they are correlated with wind direction during the daytime. The HF polarized signals may be explained by local effects of pressure fluctuations and/or by acoustic emission coming from high altitudes in particular conditions. It is only in the evening when the wind is low, that the measured polarized signals may correspond to propagating seismic waves that would be the Mars seismic background noise., This is the InSight contribution number 143 and IPGP contribution number 4183. We acknowledge NASA, CNES, their partner agencies and institutions (UKSA, SSO, DLR, JPL, IPGP-CNRS, ETHZ, IC, MPS-MPG) and the flight operations team at JPL, SISMOC, MSDS, IRIS-DMC, and PDS for providing SEED SEIS data. French authors are supported by ANR MAGIS (ANR-19-CE31-0008-08) and by CNES for SEIS science support. A. Horleston is supported by the UK Space Agency through grant #ST/R002096/1. M. Schimmel is supported by the SANIMS project (RTI2018-095594-B-I00, MICINN, Spain).

International audience; The seismometer deployed on the surface of Mars as part of the InSight mission (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) has recorded several hundreds of marsquakes in the first 478 sols after landing. The majority of these are classified as high-frequency (HF) events in the frequency range from approximately 1 to 10 Hz on Mars' surface. All the HF events excite a resonance around 2.4 Hz and show two distinct but broad arrivals of seismic energy that are separated by up to 450 s. Based on the frequency content and vertical-to-horizontal energy ratio, the HF event family has been subdivided into three event types, two of which we show to be identical and only appear separated due to the signal-to-noise ratio. We show here that the envelope shape of the HF events is explained by guided Pg and Sg phases in the Martian crust using simple layered models with scattering. Furthermore, the relative travel times between these two arrivals can be related to the epicentral distance, which shows distinct clustering. The rate at which HF events are observed varies by an order of magnitude over the course of one year and cannot be explained by changes of the background noise only. The HF content and the absence of additional seismic phases constrain crustal attenuation and layering, and the coda shape constrains the diffusivity in the uppermost shallow layers of Mars.

Seismic observations involve signals that can be easily masked by noise injection. For the NASA Mars lander InSight, the atmosphere is a significant noise contributor, impeding the identification of seismic events for two thirds of a Martian day. While the noise is below that seen at even the quietest sites on Earth, the amplitude of seismic signals on Mars is also considerably lower, requiring an understanding and quantification of environmental injection at unprecedented levels. Mars' ground and atmosphere are a continuously‐coupled seismic system, and although atmospheric functions are of distinct origins, the superposition of these noise contributions is poorly understood, making separation a challenging task. We present a novel method for partitioning the observed signal into seismic and environmental contributions. Atmospheric pressure and wind fluctuations are shown to exhibit temporal cross‐frequency coupling across multiple bands, injecting noise that is neither random nor coherent. We investigate this through comodulation, quantifying the synchrony of the seismic motion, wind and pressure signals. By working in the time‐frequency domain, we discriminate between the different origins of underlying processes and determine the site's environmental sensitivity. Our method aims to create a virtual vault at InSight's landing site on Mars, shielding the seismometers with effective post‐processing in lieu of a physical vault. This allows us to describe the environmental and seismic signals over a sequence of sols, to quantify the wind and pressure injection and estimate the seismic content of possible marsquakes with a signal‐to‐noise ratio that can be quantified in terms of environmental independence. Finally, we exploit the relationship between the comodulated signals to identify their sources., Journal of Geophysical Research: Planets, 126 (4), ISSN:0148-0227, ISSN:2169-9097

The InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) 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., We acknowledge NASA, CNES, their partner agencies and institutions (UKSA, SSO, DLR, JPL, IPGP-CNRS, ETHZ, IC, MPS-MPG) and the flight operations team at JPL, SISMOC, MSDS, IRIS-DMC and PDS for providing SEED SEIS data. We also acknowledge the funding by (1) Swiss National Science Foundation and French Agence Nationale de la Recherche (SNF-ANR project “Seismology on Mars”, ANR-14-CE36-0012-02 and MAGIS, ANR-19-CE31-0008-08), (2) Swiss State Secretariat for Education, Research and Innovation (SEFRI project “MarsQuake Service-Preparatory Phase”), (3) ETH Research grant ETH-06 17-02 and, for French co-authors, (4) the French Space agency CNES. Additional support came from the Swiss National Supercomputing Centre (CSCS) under project ID s922. AH is funded by UKSA through grant #ST/R002096/1. Visualizations were created using Matplotlib (Hunter, 2007). The data was processed with NumPy (Oliphant, 2006), Scipy (Jones et al., 2001), ObsPy (Krischer et al., 2015) and custom software developed by gempa GmbH. This paper is InSight Contribution Number 150.

The instrument package SEIS (Seismic Experiment for Internal Structure) with the three very broadband and three short‐period seismic sensors is installed on the surface on Mars as part of NASA's InSight Discovery mission. When compared to terrestrial installations, SEIS is deployed in a very harsh wind and temperature environment that leads to inevitable degradation of the quality of the recorded data. One ubiquitous artifact in the raw data is an abundance of transient one‐sided pulses often accompanied by high‐frequency spikes. These pulses, which we term “glitches”, can be modeled as the response of the instrument to a step in acceleration, while the spikes can be modeled as the response to a simultaneous step in displacement. We attribute the glitches primarily to SEIS‐internal stress relaxations caused by the large temperature variations to which the instrument is exposed during a Martian day. Only a small fraction of glitches correspond to a motion of the SEIS package as a whole caused by minuscule tilts of either the instrument or the ground. In this study, we focus on the analysis of the glitch+spike phenomenon and present how these signals can be automatically detected and removed from SEIS's raw data. As glitches affect many standard seismological analysis methods such as receiver functions, spectral decomposition and source inversions, we anticipate that studies of the Martian seismicity as well as studies of Mars' internal structure should benefit from deglitched seismic data., Plain Language Summary: The instrument package SEIS (Seismic Experiment for Internal Structure) with two fully equipped seismometers is installed on the surface of Mars as part of NASA's InSight Discovery mission. When compared to terrestrial installations, SEIS is more exposed to wind and daily temperature changes that leads to inevitable degradation of the quality of the recorded data. One consequence is the occurrence of a specific type of transient noise that we term “glitch”. Glitches show up in the recorded data as one‐sided pulses and have strong implications for the typical seismic data analysis. Glitches can be understood as step‐like changes in the acceleration sensed by the seismometers. We attribute them primarily to SEIS‐internal stress relaxations caused by the large temperature variations to which the instrument is exposed during a Martian day. Only a small fraction of glitches correspond to a motion of the whole SEIS instrument. In this study, we focus on the detection and removal of glitches and anticipate that studies of the Martian seismicity as well as studies of Mars's internal structure should benefit from deglitched seismic data., Key Points: Glitches due to steps in acceleration significantly complicate seismic records on Mars. Glitches are mostly due to relaxations of thermal stresses and instrument tilt. We provide a toolbox to automatically detect and remove glitches., Centre National d'Etudes Spatiales (CNES), InSight PSP Program, Agence Nationale de la Recherche http://dx.doi.org/10.13039/501100001665, ANR‐19‐CE31‐0008‐08

Since landing on Mars, the NASA InSight lander has witnessed eight Phobos and one Deimos transits. All transits could be observed by a drop in the solar array current and the surface temperature, but more surprisingly, for several ones, a clear signature was recorded with the seismic sensors and the magnetometer. We present a preliminary interpretation of the seismometer data as temperature‐induced local deformation of the ground, supported by terrestrial analog experiments and finite‐element modeling. The magnetic signature is most likely induced by changing currents from the solar arrays. While the observations are not fully understood yet, the recording of transit‐related phenomena with high sampling rate will allow more precise measurements of the transit times, thus providing additional constraints for the orbital parameters of Phobos. The response of the seismometer can potentially also be used to constrain the thermoelastic properties of the shallow regolith at the landing site. © 2020 American Geophysical Union, Geophysical Research Letters, 47 (19), ISSN:0094-8276, ISSN:1944-8007