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Rapid fault rupture information is important to estimate seismic ground motions and damage in large earthquakes, and is, therefore, of great value for earthquake early warning (EEW) and rapid response. The Finite-Fault Rupture Detector (FinDer) algorithm computes earthquake line-source models by comparing spatial distributions of high-frequency seismic amplitudes with precomputed template maps. FinDer is one of two seismic EEW algorithms currently adopted by the United States West Coast ShakeAlert EEW system. Between March 2018 and October 2022, FinDer detected 1048 earthquakes (2.3 ≤ M ≤ 7.1) inside the FinDer-reporting region in California, Oregon, and Washington with a median detection time of 8.5 s (75th and 95th percentile: 11.5 s, 38.9 s) after event origin and median errors (first report) of 6.7 km (75th and 95th percentile: 10.5 km, 25.5 km) in location, −0.45 s (mean ± st. dev.: 0.1 ± 5.9 s) in origin time, and 0.33 units (mean ± st. dev.: 0.33 ± 0.31 m.u.) in magnitude. Ground motions estimated using FinDer source parameters are in excellent agreement with observed peak ground accelerations, and residuals are, on average, 30% smaller than if predicted from catalog source parameters. This suggests that FinDer’s simple source parameter terms are accounting for more complex high-frequency source characteristics. This article summarizes the performance of FinDer in ShakeAlert and describes the recent improvements to the algorithm addressing issues encountered during real-time operation. This includes the handling of latent seismic data, robust event detection in regions with sparse instrumentation, enabling faster magnitude convergence in large earthquakes, use of fault- and scenario-specific earthquakes (e.g., along the Cascadia subduction zone or San Andreas fault), as well as increased robustness of FinDer in complex earthquake sequences. We demonstrate the performance of the new FinDer version 3 algorithm using waveform playbacks of selected events along the U.S. West Coast, Japan, and China, including both historic and synthetic earthquakes.

We test the behavior of the United States (US) West Coast ShakeAlert earthquake early warning (EEW) system during temporally close earthquake pairs to understand current performance and limitations. We consider performance metrics based on source parameter and ground-motion forecast accuracy, as well as on alerting timeliness. We generate ground-motion times series for synthesized earthquake sequences from real data by combining the signals from pairs of well-recorded earthquakes (4.4≤M≤7.1) using time shifts ranging from −60 to +180 s. We examine fore- and aftershock sequences, near-simultaneous events in different source regions, and simulated out-of-network and offshore earthquakes. We find that the operational ShakeAlert algorithms Earthquake Point-source Integrated Code (EPIC) and Finite-Fault Rupture Detector (FinDer) and the Propagation of Local Undamped Motion (PLUM) method perform largely as expected: EPIC provides the best source location estimates and is often fastest but can underestimate magnitudes or, in extreme cases, miss large earthquakes; FinDer provides real-time line-source models and unsaturated magnitude estimates for large earthquakes but currently cannot process concurrent events and may mislocate offshore earthquakes; PLUM identifies pockets of strong ground motion, but can overestimate alert areas. Implications for system performance are: (1) spatially and temporally close events are difficult to identify separately; (2) challenging scenarios with foreshocks that are close in space and time can lead to missed alerts for large earthquakes; and (3) in these situations the algorithms can often estimate ground motion better than source parameters. To improve EEW, our work suggests revisiting the current algorithm weighting in ShakeAlert, to continue developments that focus on using ground-motion data to aggregate alerts from multiple algorithms, and to investigate methods to optimally leverage algorithm ground-motion estimates. For testing and certification of EEW performance in ShakeAlert and other EEW systems where applicable, we also suggest that 25 of our 73 scenarios become part of the baseline data set.

We present the status of ShakeMap-EU, an initiative initially proposed in 2018 to: (i) provide an integrated archive of ShakeMaps at the European level built on EPOS Seismology (www.epos-eu.org/tcs/seismology) services & data products and modern community software; (ii) serve as a backup to authoritative ShakeMap implementations; (iii) deliver ShakeMaps for Euro-Mediterranean regions where no local capability is yet available. ShakeMap-EU products are accessible since mid-2020 at the web portal shakemapeu.ingv.it. Jointly governed by the institutions participating in the initiative, ShakeMap-EU is founded on voluntary institutional contributions and EC-funded projects. ShakeMap-EU has become a reliable European seismological service that can easily and consistently integrate authoritative models and workflows. The system is based on: (a) the latest version of ShakeMap® (usgs.github.io/shakemap); (b) the earthquake information delivered by the EMSC (www.emsc-csem.org); (c) the earthquake shaking data distributed by ORFEUS (orfeus-eu.org/data/strong); (d) the ground motion models adopted within EFEHR (www.efehr.org) for mapping seismic hazard across Europe; (d) the official ShakeMap configurations of some of the most hazardous countries in Europe. Configuration of, and input to the system are managed via a GitHub repository that allows automatic / manual triggering and interaction by authorized users. ShakeMap-EU provides a collaboration framework and laboratory for seismological agencies to address the challenges posed by the heterogeneity of ground shaking mapping strategies across Europe and the need to promote homogenization and best practices in this domain. ShakeMap-EU is used in research projects as the test platform for novel international collaborative research: among recent examples are the ongoing enhancements towards an evolutionary hazard information system including real-time seismicity characterisation and information on earthquake-induced phenomena.

The goal of earthquake early warning (EEW) is to issue an alert before the damaging seismic waves of an earthquake hit a given exposure. We develop a framework to evaluate the EEW performance in a loss-based context. We use warning time as a key performance indicator and determine statistics of warning time by loss severity to assess the rate and consistency with which an EEW system can deliver timely alerts. In the second part of this work, we develop a Genetic Algorithm approach to optimize an existing sensor network by proposing sites for new stations to enhance the EEW performance in damaging earthquakes. We demonstrate this framework for Switzerland using 2000 realizations of a 50-yr-long stochastic earthquake catalog, which samples the earthquake rate forecast of the Swiss Hazard Model in space and time. For each of the almost 24k earthquake scenario ruptures (5.0 ≤ M ≤ 7.4), we predict shaking intensities and losses (here, fatalities and injuries) at the largest Swiss cities. We find that the current Swiss Seismic Network could provide positive warning times to the affected sites for about 80% of very damaging earthquakes (≥100 fatalities) and for around 85% of earthquakes with ≥10 fatalities. Warning times of >5 s could be achieved for about 40%–55% of very damaging earthquakes and >10 s for about 35%. For around 50% of events with ≥1 fatality (≥10 injuries), EEW could provide >15 s of warning. The greatest benefit of EEW is expected in Zürich, where the population density and, consequently, absolute long-term expected losses are highest and the warning times for damaging earthquakes are often long (>15 s). Densifying the Swiss Seismic Network with additional stations can increase warning times in selected scenarios by up to 5 s. However, because it is already very dense (7 ± 5 km interstation distance), decreasing data latencies (currently ∼2 s) may be more important.

Rapid information on fault rupture geometry is critically important to assess damage and fatalities in large earthquakes and is strongly needed to coordinate rapid rescue efforts if and where necessary. Many countries around the world, however, cannot afford to operate dense seismic networks required to rapidly determine rupture geometry. In this feasibility study, we investigate if crowd-sourced felt intensity reports can be used to close this information gap and enable determination of the orientation and spatial extent of fault ruptures. We apply the Finite-Fault Rupture Detector (FinDer) algorithm to felt intensity reports collected by the European-Mediterranean Seismological Centre (EMSC). We develop an empirical relationship between the azimuthal gap between felt reports and FinDer performance for automated event selection. This gives us a dataset of 36 global earthquakes (6.0≤M≤7.3) between 2014 and 2020. We find that the resulting FinDer line-source models are generally consistent with the spatially dependent intensity patterns described by the felt reports, and in many earthquakes achieve a good agreement with the finite-source models published in the literature: for 50% of events the difference in strike is less than 30°, and for 75% less than 55°. FinDer line-source models could be calculated automatically for global earthquakes (M≥6) within 10–30 min after their occurrence, provided a sufficient number of felt reports were available. However, our proposed method not only provides faster results, but also helps to fill a general information gap for many earthquakes around the world, for which rupture geometry information is currently unavailable.

Large earthquakes, such as Wenchuan in 2008, Mw 7.9, Sichuan, China, provide an opportunity for earthquake early warning (EEW), as many heavily shaken areas are far (∼50 km) from the epicenter and warning times could be sufficient (≥5 s) to take preventive action. On the other hand, earthquakes with magnitudes larger than ∼M 6.5 are challenging for EEW because source dimensions need to be defined to adequately estimate shaking. Finite-fault rupture detector (FinDer) is an approach to identify fault rupture extents from real-time seismic records. In this study, we playback local and regional onscale strong-motion waveforms of the 2008 Mw 7.9 Wenchuan, 2013 Mw 6.6 Lushan, and 2017 Mw 6.5 Jiuzhaigou earthquakes to study the performance of FinDer for the current layout of the China Strong Motion Network. Overall, the FinDer line-source models agree well with the observed spatial distribution of aftershocks and models determined from waveform inversion. However, because FinDer models are constructed to characterize seismic ground motions (as needed for EEW) instead of source parameters, the rupture length can be overestimated for events radiating high levels of high-frequency motions. If the strong-motion data used had been available in real time, 50%–80% of sites experiencing intensity modified Mercalli intensity IV–VII (light to very strong) and 30% experiencing VIII–IX (severe to violent) could have been issued a warning with 10 and 5 s, respectively, before the arrival of the S wave. We also show that loss estimates based on the FinDer line source are more accurate compared to point-source models. For the Wenchuan earthquake, for example, they predict a four to six times larger number of fatalities and injured, which is consistent with official reports. These losses could be provided 1/2∼3 hr faster than if they were based on more complex inversion rupture models.

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°.

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.

Earthquake Early Warning (EEW) systems can trigger actions just before the shaking hits and hence mitigate the impact of damaging earthquakes. Recent studies have mainly focused on technical challenges, performance or on the attitudes of the public towards EEW systems in countries where EEW systems are already in operation or where damaging earthquakes are frequent. Building on these efforts, from the societal perspective we assess how different message elements influence the intention to take action and ability to grasp relevant information within a few seconds. Further, we explore the public attitudes towards EEW systems in a country where damaging earthquakes are expected less frequently. In a survey (N = 596, between-subjects experiment) targeting the Swiss public, we assess EEW system preferences and test different versions of EEW messages to identify elements which trigger people to take immediate actions and can be correctly recalled. Our main findings are that i) the public attitudes in countries with moderate seismic hazard are similar to attitudes in countries with high seismic hazard; ii) pictograms trigger people to protect themselves on the spot whereas maps prompt the public to look for further information or to warn others; iii) the designs preferred by the public are not always those that actually trigger them to take action; and iv) people tend to react proportionally to the hazard level. We show that insights from studies focusing on societal issues related to EEW systems can help operators define technical settings and to address specific concerns or likely misconceptions in education campaigns., International Journal of Disaster Risk Reduction, 83, ISSN:2212-4209

We evaluate methods to estimate the global seismic moment rate of a planet from the k >= 1 largest events observed during a limited and possibly short-time span, as can be expected, for example, for lander missions to Mars. The feasibility of the approach is demonstrated with a temporary broadband seismometer that was recording in the Mojave desert, California, for 86 days in 2014, and by application to the Global Centroid Moment Tensor (CMT) catalog, subsets thereof, and a catalog of stable continental regions seismicity. From the largest event observed at Goldstone alone (M-w approximate to 7.9), we estimate the Earth's global moment rate to be 1.03 x 10(22) N . m/yr, whereas an estimation based on the 10 strongest events yields a rate of 5.79 x 10(21) N . m/yr. Summation of 42 yr of Global CMT solutions results in an average of 7.61 x 10(21) N . m/yr. In general, a 2 yr interval of Global CMT solutions is sufficient to estimate the Earth's annual moment rate to within a factor of 5 or better. A series of numerical experiments with more than 560 million synthetic catalogs based on the tapered Gutenberg-Richter distribution shows that the estimation is rather insensitive against an unknown slope of the distribution, and that bias and variance of the estimator depend on the ratio between moment rate and corner moment of the size frequency distribution. Moment rates of published Mars models differ by a factor of 1000 or more. Tests with simulated catalogs show that it will be possible to reject some of these models with data returned by NASA's InSight mission after two years of nominal mission life time.

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.

International audience; One of the goals of the Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) mission is to constrain the interior structure of Mars. We present a hierarchical transdimensional Bayesian approach to extract phase velocity dispersion and interior shear‐wave velocity (VS) models from a single seismogram. This method was adapted to Mars from a technique recently developed for Earth (Xu & Beghein, 2019, https://doi.org/10.1093/gji/ggz133). Monte Carlo Markov Chains seek an ensemble of one dimensional (1‐D) VS models between a source and a receiver that can explain the observed waveform. The models obtained are used to calculate the phase velocities of fundamental and higher modes at selected periods, and a subsequent analysis is performed to assess which modes were reliably measured. An advantage of our approach is that it can also fit unknown data noise, which reduces the risk of overfitting the data. In addition, uncertainties in the source parameters can be propagated, yielding more accurate model parameter uncertainties. In this study, we first present our technique and discuss the challenges stemming from using a single station to characterize both structure and the source and from the absence of a Mars reference model. We then demonstrate the method feasibility using the Mars Structure Service blind test data and our own synthetic data, which included realistic noise levels based on the noise recorded by InSight.

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 Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) seismometer was deployed to the surface of Mars in December 2018–February 2019. The specific deployment conditions, which are very different from those of a standard broadband instrument on the Earth, result in resonances caused by different parts of the sensor assembly (SA) that are recorded by the seismometer. Here, we present and characterize the resonances known to be present in the SA and their causes to aid interpretation of the seismic signals observed on Mars. Briefly, there are resonances in the SA at about 2.9, 5.3, 9.5, 12, 14, 23–28, and 51 Hz. We discuss various methods and tests that were used to characterize these resonances, and provide evidence for some of them in data collected on Mars. In addition to their relevance for the high frequency analysis of seismic data from InSight, specifically for phase measurements near the resonant frequencies, the tests and observations described here are also of potential use in the further development of planetary seismometers, for example, for Mars, the Moon, or Europa.

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.

We analyze the performance of a prototype earthquake early warning system deployed at the National Seismological Network of Costa Rica in collaboration with the Swiss Seismological Service by presenting the real-time performance during six earthquakes (Mw 5.1-6.4) that took place during 2018 and 2019. We observe that, despite only limited efforts to optimize the existing network of 158 stations, for EEW purposes, the network density allows fast determination of source parameters using both the Virtual Seismologist and the Finite Fault Rupture Detector algorithms. Shallow earthquakes on or near-shore are routinely identified within 11–20 s of their occurrence. The warning times for the capital city of San Jose are of 43 s for epicenters located at 220 km, like for the Mw 6.4 Armuelles earthquake. On the other hand, during the time analyzed, the EEW system did not provide positive warning times for earthquakes at distances less than 40 km from San Jose. Even though large (Mw > 7) distant historical earthquakes have not caused heavy damage in San Jose, there is potential for developing an EEW system for Costa Rica, especially for the purposes of rapid earthquake notifications, disaster response management, and seismic risk mitigation., Frontiers in Earth Science, 9, ISSN:2296-6463

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

The InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) mission began collecting high quality seismic data on Mars from February 2019. This manuscript documents the seismicity observed by SEIS, InSight’s seismometer, since 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 are dominated by energy at long period below 1 second, 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.

During July 2019, a sequence of earthquakes, including an Mw 6.4 foreshock and an Mw 7.1 mainshock, occurred near Ridgecrest, California. ShakeAlert, the U.S. Geological Survey (USGS) earthquake early warning system being developed for the U.S. West Coast, was operational during this time, although public alerting was only available within Los Angeles County. ShakeAlert created alert messages for the two largest events and for many of the larger aftershocks. In this study, we dissect log files and replay data through the system to reconstruct the sequence of events and analyze the performance of the system during that period. Although the system performed reasonably well overall, the sequence also revealed various issues and short comings that will be addressed in impending and future system upgrades. ShakeAlert detected and characterized both the Mw 6.4 and Mw 7.1 earthquakes within 6.9 s of their origin times and created alert messages that were available to ShakeAlert’s pilot users. No public alerts were sent out by the ShakeAlertLA cell phone app (the only publicly available alerting method at the time), because the predicted shaking for Los Angeles County was below the app’s alerting threshold of modified Mercalli intensity 4.0. For the Mw 6.4 event, this was accurate. For the Mw 7.1 event, public alerts for Los Angeles County were warranted, but ShakeAlert underpredicted the shaking levels, because both the point-source and finite-fault algorithms underestimated the magnitude of the earthquake by 0.8 units. A number of software and hardware issues that were responsible for the magnitude underestimation of the mainshock have been identified and will be addressed in future ShakeAlert releases. We also analyze the hypothetical alerting performance of ShakeAlert had public alerting been available throughout southern California.

In early 2019, NASA's InSight lander successfully deployed a single three-component very broadband seismometer (VBB) on the surface of Mars to detect and characterize marsquakes. Using these data, ...

InSight landed on Mars in late November 2018, and the SEIS package, which consists of one short period and one very broadband sensor, was deployed on the surface shortly after. The data returned by the InSight is monitored in a timely manner by the Marsquake Service (MQS), a ground segment support group of InSight that has been set up to establish and maintain the seismicity catalogue. The MQS has at least one member on duty who routinely checks the data for any type of seismic signals. All suspicious signals are then communicated to the InSight team after evaluation.To date, MQS has identified more than 365 events which are classified into two general families as high and low frequency, with each family having unique features in terms of their energy content. The most distinct quakes detected so far belong to the low frequency family that occurred on Sol 173 and 235, and have clear P and S-wave arrivals that reveal a distance around 30 degrees east of the lander, pointing the region in the vicinity of Cerberus Fossae. In addition to the signals of seismic origin, the SEIS data contain features that originate from other sources such as atmospheric effects or electronics. Part of these non-seismic observations may resemble quakes which may lead to wrong interpretations, and therefore require careful analysis.Here, we show examples of signals of both seismic and non-seismic origins. We describe the characteristics of these observations in time and frequency domains in order to give an overview of martian data content.

InSight landed on Mars in late November 2018, and the SEIS seismometer package was fully deployed by February 2019. By January 2020, SEIS continues to exceed performance expectations in terms of observed minimum noise. The Marsquake Service (MQS) has been setup to create and curate a seismicity catalogue for Mars over the lifetime of the InSight mission. Seismic waveforms are downloaded daily from the station and are analysed and processed by the MarsQuake Service, with the goal of detecting seismic vibrations not due to local ambient sources. To this end, every precaution is applied to eliminate possible non-seismic sources, such as noise induced by atmospheric phenomena, lander vibrations and orbiter activity. At the date of submission, we have detected 365 events, of different quality and SNR levels. Signal amplitudes remain small and signal can generally only be detected at night. Some events show only low-frequency waves in the 1-10 sec band, others have a high-frequency content up to several Hz, and others have a more broad-band character. A special class of events involves the excitation of a very prominent ambient vibration at 2.4Hz. Despite the scattered nature of the energy, in many cases, distinct phases can be inferred in the waveforms. Body wave character, and back-azimuth, can only be confirmed for 3 broadband events so far. The MQS approach for determining distances from broadband events identifies phases as mantle P and S-phases and uses an a priori set of several thousand martian models, derived from geophysical, mineralogical and orbital constraints. High frequency events are currently located assuming phases are trapped crustal Pg and Sg and using a simple crustal layer. The MQS works in conjunction with the Mars Structural Service (MSS) on building and adopting updated models. The MQS consists of an international team of seismologists that screen incoming data to identify and characterise any seismicity. In this presentation, we present the MQS, demonstrate how we detect and characterise marsquakes, and describe the challenges we face dealing with the Martian dataset.

We present an updated estimate of the seismic activity rate of Mars after seven months of high-quality recording of the InSight SEIS instrument. The instrument has been deployed fully on Sol 60 (February 2, 2019) and has been recording with excellent performance since then. The first distant marsquake was observed on Sol 105 (March 14), the first local event on Sol 128 (April 7). From then until early January 2020 (Sol 400), 23 likely events and another 13 candidate events have been observed. Due to a strong diurnal variation in background noise and the generally low magnitude of the activity (compared to Earth), events have been observed only in few low-noise periods of the day. The change of seasons varied the duration of these low-noise periods over the mission, with a magnitude and time-dependent effect on detectability of events and the quantitative estimation of event rates and moment release.We present a statistical analysis of the global seismic activity level based on a preliminary seismic magnitude model, weighted by the temporal evolution of the ambient noise over half a Martian year. The resulting number of events smaller magnitude 3 is roughly consistent with the pre-mission estimate of Golombek (1992) and the medium model of Knapmeyer et al. (2006), however, as of now, there is a statistically significant lack of events above magnitude 3.5. This hints at a distribution that is skewed towards smaller events, compared to terrestrial global averages.

The national seismic networks in Central America have been developing network-based early warning since 2016 for Nicaragua, 2018 for El Salvador and 2019 for Costa Rica. This effort is part of a project with the Swiss Seismological Service (ETH Zurich) including funds for accelerograph deployment. At each network, delay for first earthquake parameter estimations have been significantly reduced by optimizing data acquisition, metadata quality, and configuration of the EEW algorithms implemented in SeisComP3, i.e. Virtual Seismologist and the Finite fault rupture Detector. Issues remain with significant numbers of deployed instrumentation that for a variety of reasons, do not optimally contribute to the EEW systems. Building on our experience so far, we design national network upgrades that will optimize the earthquake early warning performance in the Central America region, mitigating the current issues with velocimeter clipping during large events, datalogger delays, and incomplete network coverage. The new instruments have been selected after testing all available EEW-capable accelerographs natively compatible with SeisComP3 including class A force balance accelerometers as well as MEMs. To justify our instrument selection, we summarize the performance of these different instruments. We model and discuss reference maps for performance expectations, and present planned instrument vaults. Our primary focus is on minimizing first alert times but we also wish to accentuate the broad value of the network upgrade for seismological monitoring showing changes in the magnitude of completeness in the region. We demonstrate the value of the network upgrade for earthquake early warning with real-time processing simulation using synthetic data for the maximum magnitude earthquake expected for the Central America subduction zone.

About one year after the successful deployment of the InSight (Interior exploration using Seismic Investigations, Geodesy and Heat Transport) very-broadband seismometer on the Martian surface and the identification of several hundreds of seismic events in the current InSight catalogue, we revise the pre-launch magnitude relations in Böse et al. (2018) to account for the seismic and noise characteristics observed on Mars. The data collected so far indicate that (1) marsquakes are characterized by energy between ~0.1-10Hz; (2) neither surface-wave nor secondary phase arrivals have yet been identified; and (3) a class of high-frequency events exists that are visible mainly as an increased excitation of the 2.4Hz mode. In view of these observations, we up-date scaling relations for the spectral and body-wave magnitudes, and introduce a new magnitude scale for high-frequency events. We use these relations to determine that the magnitudes of events in the current InSight catalogue range between 1.0 and 4.0.

We analyze the sequence of seismic events of different types as recorded by the SEIS instrument of the InSight mission. After several weeks without any detection, event counts started to increase at the end of May 2019. The majority of recorded events belongs to the class of 2.4 Hz events, which prominently excite a continuously observed natural resonance frequency.After a sudden onset of seismic detections by the end of May 2019 (about sol 180, LS≈32°), especially the combined event rate of the High Frequency, Very High Frequency, and 2.4 Hz family of events increased from 3.6 events/sol in June 2019 to more than 9 events/sol until late August 2019, i.e. increased by a factor of about 3.Estimating event rates as if events are the result of a constant-rate Poisson process leads to contradictions with the statistical properties of those, either in the cumulative event count or in the lag time distribution. These contradictions can be overcome by assuming a step-wise increase of the event rate.Any deviation from a purely random occurrence of quakes, in both time and space, requires a mechanism to suppress or support the source process. The seismic activity of the Moon is mainly controlled by tidal deformation, at least in terms of source time. What controls the event rate of Martian high frequency events is currently elusive.

The InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) mission landed in Elysium Planitia on Mars on 26 November 2018 and fully deployed its seismometer by the end of February 2019. The mission aims to detect, characterize and locate seismic activity on Mars, and to further constrain the internal structure, composition and dynamics of the planet. Here, we present seismometer data recorded until 30 September 2019, which reveal that Mars is seismically active. We identify 174 marsquakes, comprising two distinct populations: 150 small-magnitude, high-frequency events with waves propagating at crustal depths and 24 low-frequency, subcrustal events of magnitude Mw 3–4 with waves propagating at various depths in the mantle. These marsquakes have spectral characteristics similar to the seismicity observed on the Earth and Moon. We determine that two of the largest detected marsquakes were located near the Cerberus Fossae fracture system. From the recorded seismicity, we constrain attenuation in the crust and mantle, and find indications of a potential low-S-wave-velocity layer in the upper mantle. © 2020, The Author(s), under exclusive licence to Springer Nature Limited., We acknowledge NASA, CNES and its partner agencies and institutions (UKSA, SSO, DLR, JPL, IPGP-CNRS, ETHZ, IC and MPS-MPG) and the flight operations team at JPL, SISMOC, MSDS, IRIS-DMC and PDS for providing SEIS data. The Swiss co-authors were jointly funded by (1) the Swiss National Science Foundation and French Agence Nationale de la Recherche (SNF-ANR project 157133 ‘Seismology on Mars’), (2) the Swiss National Science Foundation (SNF project 172508 ‘Mapping the internal structure of Mars’), (3) the Swiss State Secretariat for Education, Research and Innovation (SEFRI project ‘MarsQuake Service-Preparatory Phase’) and (4) ETH Research grant no. ETH-06 17-02. Additional support came from the Swiss National Supercomputing Centre (CSCS) under project ID s922. The Swiss contribution in the implementation of the SEIS electronics was made possible by funding from the federal Swiss Space Office (SSO) and contractual and technical support from the ESA-PRODEX office. The French Team acknowledge the French Space Agency CNES, which has supported and funded all SEIS-related contracts and CNES employees, as well as CNRS and the French team universities for personal and infrastructure support. Additional support was provided by ANR (ANR-14-CE36-0012-02 and ANR-19-CE31-0008-08) and, for the IPGP team, by the UnivEarthS Labex programme (ANR-10-LABX-0023), IDEX Sorbonne Paris Cité (ANR-11-IDEX-0005-0). SEIS-SP development and delivery were funded by the UK Space Agency. A portion of the work was carried out at the InSight Project at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. The MPS SEIS team acknowledges funding for development of the SEIS leveling system by the DLR German Space Agency. We thank gempa GmbH for software development related to the MQS tools. This paper is InSight contribution number 102.

This report summarizes the seismicity in Switzerland and surrounding regions in the years 2015 and 2016. In 2015, the Swiss Seismological Service detected and located 735 earthquakes in the region under consideration. With a total of 20 earthquakes of magnitude ML ≥ 2.5, the seismic activity of potentially felt events in 2015 was close to the average of 23 earthquakes over the previous 40 years. Seismic activity was above average in 2016 with 872 located earthquakes of which 31 events had ML ≥ 2.5. The strongest event in the analyzed period was the ML 4.1 Salgesch earthquake, which occurred northeast of Sierre (VS) in October 2016. The event was felt in large parts of Switzerland and had a maximum intensity of V. Derived focal mechanisms and relative hypocenter relocations of aftershocks image a SSE dipping reverse fault, which likely also hosted an ML 3.9 earthquake in 2003. Another remarkable earthquake sequence in the Valais occurred close to Sion with four felt events (ML 2.7–3.2) in 2015/16. We associate this sequence with a system of WNW-ESE striking fault segments north of the Rhone valley. Similarities with a sequence in 2011, which was located about 10 km to the NE, suggest the existence of an en-echelon system of basement faults accommodating dextral slip along the Rhone-Simplon line in this area. Another exceptional earthquake sequence occurred close to Singen (Germany) in November 2016. Relocated hypocenters and focal mechanisms image a SW dipping transtensional fault segment, which is likely associated with a branch of the Hegau-Bodensee Graben. On the western boundary of this graben, micro-earthquakes close to Schlattingen (TG) in 2015/16 are possibly related to a NE dipping branch of the Neuhausen Fault. Other cases of earthquakes felt by the public during 2015/16 include earthquakes in the region of Biel, Vallorcine, Solothurn, and Savognin.

The InSight (Interior exploration using Seismic Investigations, Geodesy and Heat Transport) lander will deploy a seismic monitoring package on Mars in November 2018. In prepara- tion for the data return, we prepared a blind test in which we invite participants to detect and characterize seismicity included in a synthetic dataset of continuous waveforms from a single station that mimics both the streams of data that will be available from InSight, as well as expected tectonic and impact seismicity and noise conditions on Mars. We expect that the test will ultimately improve and extend the current set of methods that the InSight team plan to use in routine analysis of the Martian dataset.

The InSight mission will land a single seismic station on Mars in November 2018, and the resultant seismicity catalog will be a key component for studies aiming to understand the interior structure of the planet. Here, we present a preliminary version of the web services that will be used to distribute the event and station metadata in practice, employing synthetic seismograms generated for Mars using a catalog of expected seismicity. Our seismicity catalog consists of 120 events with double-couple source mechanisms only. We also provide Green’s functions databases for a total of 16 structural models, which are constructed to reflect one-dimensional thin (30 km) and thick (80 km) Martian crust with varying seismic wave speeds and densities, combined with two different profiles for temperature and composition for the mantle. Both the Green’s functions databases and the precomputed seismograms are accessible online. These new utilities allow the researchers to either download the precomputed synthetic waveforms directly, or produce customized data sets using any desired source mechanism and event distribution via our servers.

By the end of 2018, 42 years after the landing of the two Viking seismometers on Mars, InSight will deploy onto Mars’ surface the SEIS (Seismic Experiment for Internal Structure) instrument; a six-axes seismometer equipped with both a long-period three-axes Very Broad Band (VBB) instrument and a three-axes short-period (SP) instrument. These six sensors will cover a broad range of the seismic bandwidth, from 0.01 Hz to 50 Hz, with possible extension to longer periods. Data will be transmitted in the form of three continuous VBB components at 2 sample per second (sps), an estimation of the short period energy content from the SP at 1 sps and a continuous compound VBB/SP vertical axis at 10 sps. The continuous streams will be augmented by requested event data with sample rates from 20 to 100 sps. SEIS will improve upon the existing resolution of Viking’s Mars seismic monitoring by a factor of ∼2500 at 1 Hz and ∼200000 at 0.1 Hz. An additional major improvement is that, contrary to Viking, the seismometers will be deployed via a robotic arm directly onto Mars’ surface and will be protected against temperature and wind by highly efficient thermal and wind shielding. Based on existing knowledge of Mars, it is reasonable to infer a moment magnitude detection threshold of Mw∼3 at 40∘ epicentral distance and a potential to detect several tens of quakes and about five impacts per year. In this paper, we first describe the science goals of the experiment and the rationale used to define its requirements. We then provide a detailed description of the hardware, from the sensors to the deployment system and associated performance, including transfer functions of the seismic sensors and temperature sensors. We conclude by describing the experiment ground segment, including data processing services, outreach and education networks and provide a description of the format to be used for future data distribution., Space Science Reviews, 215 (1), ISSN:1572-9672, ISSN:0038-6308

In December 2018, the National Aeronautics and Space Administration (NASA) Interior exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) mission deployed a seismometer on the surface of Mars. In preparation for the data analysis, in July 2017, the marsquake service initiated a blind test in which participants were asked to detect and characterize seismicity embedded in a one Earth year long synthetic data set of continuous waveforms. Synthetic data were computed for a single station, mimicking the streams that will be available from InSight as well as the expected tectonic and impact seismicity, and noise conditions on Mars (Clinton et al., 2017). In total, 84 teams from 20 countries registered for the blind test and 11 of them submitted their results in early 2018. The collection of documentations, methods, ideas, and codes submitted by the participants exceeds 100 pages. The teams proposed well established as well as novel methods to tackle the challenging target of building a global seismicity catalog using a single station. This article summarizes the performance of the teams and highlights the most successful contributions., This work was jointly funded by Swiss National Science Foundation and French Agence Nationale de la Recherche (SNF-ANR project 157133 "Seismology on Mars"); Swiss State Secretariat for Education, Research and Innovation (project "MarsQuake Service-Preparatory Phase"); and ETH Zurich (project "Preparatory phase for Mars InSight Ground Segment Support"). Additional support came from the Swiss National Supercomputing Centre (CSCS) under Project ID s682. Some of the research described in this article was supported by the Interior exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) project, Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (NASA). The Houston team was partially funded by EAR-1621878. A. Spiga and L. Rolland acknowledge funding by Centre National d'Etudes Spatiales (CNES). This article constitutes InSight Contribution Number 93.

Impact investigations will be an important aspect of the InSight mission. One of the scientific goals of the mission is a measurement of the current impact rate at Mars. Impacts will additionally inform the major goal of investigating the interior structure of Mars. In this paper, we review the current state of knowledge about seismic signals from impacts on the Earth, Moon, and laboratory experiments. We describe the generalized physical models that can be used to explain these signals. A discussion of the appropriate source time function for impacts is presented, along with spectral characteristics including the cutoff frequency and its dependence on impact momentum. Estimates of the seismic efficiency (ratio between seismic and impact energies) vary widely. Our preferred value for the seismic efficiency at Mars is $5 \times 10^{- 4}$ , which we recommend using until we can measure it during the InSight mission, when seismic moments are not used directly. Effects of the material properties at the impact point and at the seismometer location are considered. We also discuss the processes by which airbursts and acoustic waves emanate from bolides, and the feasibility of detecting such signals. We then consider the case of impacts on Mars. A review is given of the current knowledge of present-day cratering on Mars: the current impact rate, characteristics of those impactors such as velocity and directions, and the morphologies of the craters those impactors create. Several methods of scaling crater size to impact energy are presented. The Martian atmosphere, although thin, will cause fragmentation of impactors, with implications for the resulting seismic signals. We also benchmark several different seismic modeling codes to be used in analysis of impact detections, and those codes are used to explore the seismic amplitude of impact-induced signals as a function of distance from the impact site. We predict a measurement of the current impact flux will be possible within the timeframe of the prime mission (one Mars year) with the detection of ∼ a few to several tens of impacts. However, the error bars on these predictions are large. Specific to the InSight mission, we list discriminators of seismic signals from impacts that will be used to distinguish them from marsquakes. We describe the role of the InSight Impacts Science Theme Group during mission operations, including a plan for possible night-time meteor imaging. The impacts detected by these methods during the InSight mission will be used to improve interior structure models, measure the seismic efficiency, and calculate the size frequency distribution of current impacts.

International audience; The InSight mission expects to operate a geophysical observatory on Mars for at least two Earth years from late 2018. InSight includes a seismometer package, SEIS. The Marsquake Service (MQS) is created to provide a first manual review of the seismic data returned from Mars. The MQS will detect, locate, quantify and classify seismic events, whether tectonic or impact in origin. A suite of new and adapted methodologies have been developed to allow location and quantification of seismic events at the global scale using a single station, and a software framework has been developed that supports these methods. This paper describes the expected signals that will be recorded by SEIS, the methods used for their identification and interpretation, and reviews the planned MQS operational procedures. For each seismic event, the MQS will locate events using all available body and surface phases, using the best estimates of the Martian structure, which will become more accurate as more Martian marsquakes are identified and located. The MQS will curate the Mars seismicity catalogue, with all events being relocated to use revised suites of structure models as they are introduced.

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. ISSN:0031-9201 ISSN:1872-7395

International audience; In anticipation of the upcoming 2018 InSight (Interior exploration using Seismic Investigations, Geodesy and Heat Transport) Discovery mission to Mars, we calibrate magnitude scales for marsquakes that incorporate state-of-the-art knowledge on Mars interior structure and the expected ambient and instrumental noise. We regress magnitude determinations of 2600 randomly distributed marsquakes, simulated with a spectral element method for 13 published 1D structural models of Mars' interior. The continuous seismic data from InSight will be returned at 2 samples per second. To account for this limited bandwidth as well as for the expected noise conditions on Mars, we define and calibrate six magnitude scales: (1) local Mars magnitude M-L(Ma) at a period of 3 s for marsquakes at distances of up to 10 degrees; (2) P-wave magnitude m(b)(Ma); (3) S-wave magnitude m(bS)(Ma) each defined at a period of 3 s and calibrated for distances from 5 degrees to 100 degrees; (4) surface-wave magnitude M-s(Ma) defined at a period of 20 s, as well as (5) moment magnitudes M-FB(Ma); and (6) M-F(Ma) computed from the low-frequency (10-100 s) plateau of the displacement spectrum for either body waves or body and surface waves, respectively; we calibrate scales (4)-(6) for distances from 5 degrees to 180 degrees. We regress stable calibrations of the six scales with respect to the seismic moment magnitude at M-w 5.5 by correcting filtered phase amplitudes for attenuation with distance and source depth. Expected errors in epicentral distance and in source depth (25% and 20 km, respectively) translate into magnitude errors of 0.1-0.3 units. We validate our magnitude relations with an independent test dataset of 2600 synthetic marsquakes (1.0 15 degrees are expected to be hidden in the Mars background noise and will likely not be detectable.

Recent studies suggest that small and large earthquakes nucleate similarly, and that they often have indistinguishable seismic waveform onsets. The characterization of earthquakes in real time, such as for earthquake early warning, therefore requires a flexible modeling approach that allows a small earthquake to become large as fault rupture evolves over time. Here, we present a modeling approach that generates a set of output parameters and uncertainty estimates that are consistent with both small/moderate (≤M6.5) and large earthquakes (>M6.5) as is required for a robust parameter interpretation and shaking forecast. Our approach treats earthquakes over the entire range of magnitudes (>M2) as finite line-source ruptures, with the dimensions of small earthquakes being very small (