The Marsquake catalogue from InSight, sols 0–478 Clinton, John F.; Ceylan, Savas; van Driel, Martin ...
Physics of the earth and planetary interiors,
January 2021, 2021-01-00, 2021-01, Letnik:
310
Journal Article
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The InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) mission began collecting high quality seismic data on Mars in February 2019. This manuscript documents the ...seismicity observed by SEIS, InSight's seismometer, from this time until the end of March 2020. Within the InSight project, the Marsquake Service (MQS) is responsible for prompt review of all seismic data collected by InSight, detection of events that are likely to be of seismic origin, and curation and release of seismic catalogues. In the first year of data collection, MQS have identified 465 seismic events that we interpret to be from regional and teleseismic marsquakes. Seismic events are grouped into 2 different event families: the low frequency family is dominated by energy at long period below 1 s, and the high frequency family primarily include energy at and above 2.4 Hz. Event magnitudes, from Mars-specific scales, range from 1.3 to 3.7. A third class of events with very short duration but high frequency bursts have been observed 712 times. These are likely associated with a local source driven by thermal stresses. This paper describes the data collected so far in the mission and the procedures under which MQS operates; summarises the content of the current MQS seismic catalogue; and presents the key features of the events we have observed so far, using the largest events as examples.
•The Marsquake Service is providing updated catalogues of Martian seismicity as recorded on InSight.•465 distant marsquakes have been identified in the first 478 martian days (sol) since InSight landed.•This version of the catalogue includes an additional 712 events that may be due to local cracking from thermal forcing.
S1222a—The Largest Marsquake Detected by InSight Kawamura, Taichi; Clinton, John F.; Zenhäusern, Géraldine ...
Geophysical research letters,
16 March 2023, Letnik:
50, Številka:
5
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NASA's InSight has detected a large magnitude seismic event, labeled S1222a. The event has a moment magnitude of MWMa ${\mathrm{M}}_{\mathrm{W}}^{\text{Ma}}$4.7, with five times more seismic moment ...compared to the second largest event. The event is so large that features are clearly observed that were not seen in any previously detected events. In addition to body phases and Rayleigh waves, we also see Love waves, minor arc surface wave overtones, and multi‐orbit surface waves. At long periods, the coda event exceeds 10 hr. The event locates close to the North‐South dichotomy and outside the tectonically active Cerberus Fossae region. S1222a does not show any evident geological or tectonic features. The event is extremely rich in frequency content, extending from below 1/30 Hz up to 35 Hz. The event was classified as a broadband type event; we also observe coda decay and polarization similar to that of very high frequency type events.
Plain Language Summary
After 3 years of seismic monitoring of Mars by InSight Seismic Experiment for Interior Structure instrument, we detected a marsquake largest ever observed during the mission. The event is larger by factor of 5 in seismic moment compared to previously detected events. With such an energetic event, we discovered various seismic features that was never observed before. For the first time, we were able to detect body waves and surface waves with their overtones. The large variety of detected seismic phases will enable us to probe the internal structure of Mars. Second, the event was located outside a well‐known seismically active region of Cerberus Fossae. This might indicate that event do not come from the same fault system with other major marsquakes. Finally, this event shows simultaneously features of marsquakes that were previously classified into different types. S1222a is classified as a broadband event with a wide frequency range of seismic energy. At the same time, the coda shape and decay at high frequency resembles that of very high frequency type events. It was an open question how different types of marsquakes are excited of what makes such differences and such event will be a key to uncover such mystery of marsquakes.
Key Points
InSight detected on 4 May 2022 a MWMa ${\mathrm{M}}_{\mathrm{W}}^{\text{Ma}}$4.7 marsquake, S1222a, which is the largest seismic event detected so far
The exceptional signal‐to‐noise allows multiple phases to be identified, with a rich collection of surface waves
S1222a was located 37° southeast of the InSight landing site and close to the Martian dichotomy boundary
NASA's Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) seismometer has been recording Martian seismicity since early 2019, and to date, over 1,300 marsquakes ...have been cataloged by the Marsquake Service (MQS). Due to typically low signal‐to‐noise ratios (SNR) of marsquakes, their detection and analysis remain challenging: while event amplitudes are relatively low, the background noise has large diurnal and seasonal variations and contains various signals originating from the interactions of the local atmosphere with the lander and seismometer system. Since noise can resemble marsquakes in a number of ways, the use of conventional detection methods for catalog curation is limited. Instead, MQS finds events through manual data inspection. Here, we present MarsQuakeNet (MQNet), a deep convolutional neural network for the detection of marsquakes and the removal of noise contamination. Based on three‐component seismic data, MQNet predicts segmentation masks that identify and separate event and noise energy in time‐frequency domain. As the number of cataloged MQS events is small, we combine synthetic event waveforms with recorded noise to generate a training data set. We apply MQNet to the entire continuous 20 samples‐per‐second waveform data set available to date (>1,000 Martian days), for automatic event detection and for retrieving denoised amplitudes. The algorithm reproduces all high quality, as well as majority of low quality events in the manual, carefully curated MQS catalog. Furthermore, MQNet detects ∼60% additional events that were previously unknown with mostly low SNR, that are verified in manual review. Our analysis on the event rate confirms seasonal trends and shows a substantial increase in the second Martian year.
Plain Language Summary
Interior Exploration using Seismic Investigations, Geodesy and Heat Transport's seismometer on Mars has recorded over 1,300 marsquakes since its full deployment in early 2019. Marsquakes are often weak compared to the seismic background noise, which makes their detection and analysis challenging. For this reason, the current event catalog relies on identifying events in manual data review, which can result in an inconsistent event catalog with weak events being missed and quality standards changing over time. In this study, we use a type of artificial neural network for the automatic detection of marsquakes and to separate even signal and background noise. Since these artificial neural networks usually require many examples to learn from but the number of known marsquakes is low, we generate synthetic marsquake examples to train the network. We run the detection algorithm across the mission and compare its performance to the manually compiled event catalog: the algorithm can also detects the majority of identified marsquakes and additionally finds many weaker, previously missing events, thereby extending the number of known marsquakes by ∼60%, from 1,297 to 2,079. Further, our results show substantial variations in event numbers throughout the mission.
Key Points
Marsquakes recorded by Interior Exploration using Seismic Investigations, Geodesy and Heat Transport's seismometer are challenging to detect and analyze due to typically low signal‐to‐noise‐ratio
We present MarsQuakeNet—a convolutional neural network for marsquake detection and denoising—trained on synthetic data
Our catalog is consistent with existing manual catalog, extends it by 60% and confirms significant changes in event rate across Martian years
We present a new class of seismic signals that are recorded by the seismometer placed on the surface of Mars as part of the NASA InSight mission. The signals, termed super high frequency (SF) events, ...are of short duration (∼20 s), are often similar in amplitude, and feature high‐frequency energy between ∼5 and 30 Hz that is dominant on the horizontal components. For detection and characterization of SF events, we employ the available continuous 20 samples per second (sps) data from the Very Broadband instrument. Due to bandwidth limitations, 100 sps data from the short‐period sensor are only partially obtainable, but they aid in analysis of the frequency content above 10 Hz and in distinguishing the events from high‐frequency noise. From June 2019 to May 2020, 780 SF events have been detected. The events observed occur in repeatable patterns that last for weeks. Initially, the SF events were clustered in the hours before sunset, but more recently, they have been distributed across the evening period. Based on template matching techniques, we have identified 16 distinct families that generally follow the temporal clusters. A thermal origin of these events is suggested, since the majority of the events fall within a ±2 h time window around sunset with extreme temperature changes. The SF events have similarities with thermal events observed on the lunar surface from data collected during the Apollo missions.
Plain Language Summary
The seismometers on Mars are recording high‐frequency signals of short duration. Seven hundred and eighty of these events have been found so far, that can be categorized into families with comparable signal shape. Each family repeats for a limited number of days at similar times of the day. At first, they occurred at or shortly before sunset, but more recently they are being observed later in the Martian evening. We infer these signals originate from close to the lander but not the lander itself, and may be related to thermal cracking, like the lunar thermal events observed during the Apollo missions.
Key Points
Super high frequency events are a class of signals observed by the InSight seismometer on Mars
Seven hundred and eighty events have been observed, typically lasting 20 s with energy mainly on horizontal components between 5 and 30 Hz
Events appear in clusters and are likely associated with local thermal sources similar to observations on the Moon
The InSight mission (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) has been collecting high-quality seismic data from Mars since February 2019, shortly after its ...landing. The Marsquake Service (MQS) is the team responsible for the prompt review of all seismic data recorded by the InSight's seismometer (SEIS), marsquake event detection, and curating seismicity catalogues. Until sol 1011 (end of September 2021), MQS have identified 951 marsquakes that we interpret to occur at regional and teleseismic distances, and 1062 very short duration events that are most likely generated by local thermal stresses nearby the SEIS package. Here, we summarize the seismic data collected until sol 1011, version 9 of the InSight seismicity catalogue. We focus on the significant seismicity that occurred after sol 478, the end date of version 3, the last catalogue described in a dedicated paper. In this new period, almost a full Martian year of new data has been collected, allowing us to observe seasonal variations in seismicity that are largely driven by strong changes in atmospheric noise that couples into the seismic signal. Further, the largest, closest and most distant events have been identified, and the number of fully located events has increased from 3 to 7. In addition to the new seismicity, we document improvements in the catalogue that include the adoption of InSight-calibrated Martian models and magnitude scales, the inclusion of additional seismic body-wave phases, and first focal mechanism solutions for three of the regional marsquakes at distances ∼30°.
•The V9 catalogue includes 951 events, of which 486 are new since the previous report.•Multiple large marsquakes with MWMa 4.0–4.2 were recorded.•Some new events are within 100 km of the lander and beyond the core shadow which were not seen before.•Four events are located close to the lander, which include chirps and are interpreted as meteorite impacts.•The catalogue also includes 1062 very local events that may be due to thermal stresses.
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.
•This paper is a summary of the InSight data from Mars, mainly focusing on the seismic data set.•We describe the signals of non-seismic origins that potentially can cause misinterpretations as marsquakes.•We outline the common features in the data such as artifacts and patterns for future reference that may be unfamiliar to the scientific community.
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°.
Abstract
For over three Earth years the Marsquake Service has been analyzing the data sent back from the Seismic Experiment for Interior Structure—the seismometer placed on the surface of Mars by ...NASA’s InSight lander. Although by October 2021, the Mars seismic catalog included 951 events, until recently all these events have been assessed as lying within a radius of 100° of InSight. Here we report two distant events that occurred within days of each other, located on the far side of Mars, giving us our first glimpse into Mars’ core shadow zone. The first event, recorded on 25 August 2021 (InSight sol 976), shows clear polarized arrivals that we interpret to be PP and SS phases at low frequencies and locates to Valles Marineris, 146° ± 7° from InSight. The second event, occurring on 18 September 2021 (sol 1000), has significantly more broadband energy with emergent PP and SS arrivals, and a weak phase arriving before PP that we interpret as Pdiff. Considering uncertain pick times and poorly constrained travel times for Pdiff, we estimate this event is at a distance between 107° and 147° from InSight. With magnitudes of MwMa 4.2 and 4.1, respectively, these are the largest seismic events recorded so far on Mars.
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