The Seismicity of Mars Observed by the NASA InSight Mission

In an attempt to improve the quality of the seismic signals provided by the seismometer of the InSight mission (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) on Mars, part of the tether linking the seismometer to the InSight lander was buried by some regolith using the scoop of the articulated robotic arm. The regolith in a source area was scraped into piles, scooped and dumped by the scoop from a height of ∼50 cm above the surface onto the tether. Part of the regolith was carried away by the wind and dispersed 1–2 m downwind, as evidenced by the comparison between images taken from the lander before and after the regolith pouring. Using both ballistic trajectory and wind dispersion effects as a sorter, the grain size range was determined through numerical fluid mechanics simulations. The trajectory of the poured grains is determined by the Martian atmospheric and gravimetry conditions, the initial conditions of scoop pouring and grain lithology. The spatial grain distribution on the ground shows a downwind decrease in grain size from the pouring point, with a size ranging from 1 mm near the dump point to ∼100 μm at the farthest area observed on the images. We find that the deposit of grains coarser than 500 μm is controlled mainly by gravity. Grains finer than 100 μm are present in the regolith, but they are not quantifiable with this method because they are blown away by the wind.

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Revisiting Martian seismicity with deep learning-based denoising

Dahmen,

Clinton,

Stähler

et al. 2024

Geophysical Journal International

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Summary The analysis of seismic events recorded by NASA’s InSight seismometer remains challenging, given their commonly low magnitudes and large epicentral distances, and concurrently, strongly varying background noise. These factors collectively result in low signal-to-noise ratios (SNR) across most event recordings. We use a deep learning denoising approach to mitigate the noise contamination, aiming to enhance the data analysis and the seismic event catalogue. Our systematic tests demonstrate that denoising performs comparable to fine-tuned bandpass filtering at high SNRs, but clearly outperforms it at low SNRs with respect to accurate waveform and amplitude retrieval, as well as onset picking. We review the denoised waveform data of all 98 low frequency events in the Marsquake Service catalogue version 14, and improve their location when possible through the identification of phase picks and back azimuths, while ensuring consistency with the raw data. We demonstrate that several event waveforms can be explained by marsquake doublets - two similarly strong quakes in spatio-temporal proximity that result in overlapping waveforms at InSight - and we locate them in Cerberus Fossae. Additionally, we identify and investigate aftershocks and an event sequence consisting of numerous relatively high magnitude marsquakes occurring within hours at epicentral distances beyond Cerberus Fossae. As a result of this review and interpretation, we extend the catalogue in event numbers (+8%), in events with epicentral distances and magnitudes (+50%), and events with back azimuths and a resulting full locations (+46%), leading to a more comprehensive description of Martian seismicity.

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The Seismicity of Mars Observed by the NASA InSight Mission

Cited by 5 publications

References 34 publications

Design, optimization, and autonomous construction of Martian infrastructure including slabs using in-situ CO2-based polyethylene

Design, optimization, and autonomous construction of Martian infrastructure including slabs using in-situ CO2-based polyethylene

Using Wind Dispersion Effects During the InSight Tether Burial Activities to Better Constrain the Regolith Grain Size Distribution

Revisiting Martian seismicity with deep learning-based denoising

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