Magnitude Scales for Marsquakes Calibrated from InSight Data

Maren Böse*, Anna C Horleston, Simon C. Stähler, D Deichmann, D. Giardini, John Clinton, P. Lognonné, Savas Ceylan, Martin van Driel, C. Charalambous, Nikolaj L. Dahmen, Taichi Kawamura, Amir Khan, Martin Knapmeyer, Guenolé Orhand-Mainsant, John-Robert Scholz, Fabian Euchner, W. B. Banerdt

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

Abstract

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, MMaw,spec⁠, mMab⁠, and mMabS⁠, and introduce a new magnitude scale, MMa2.4⁠, 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.
Original languageEnglish
JournalBulletin of the Seismological Society of America
Early online date22 Jun 2021
DOIs
Publication statusE-pub ahead of print - 22 Jun 2021

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