Companion guide to the Marsquake Catalog from InSight, Sols 0-478: data content and non-seismic events

Abstract

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 till 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 events.

Detection, Analysis, and Removal of Glitches From InSight's Seismic Data From Mars

“…For this glitch pattern, however, we observe an additional 4.2 Hz ringing in some cases for the duration of the glitch, something not expected for an unhindered SEIS tilt. This occasional ringing could be related to other short duration data artifacts (“donks”, Ceylan et al, 2020) we observe mostly in data with higher sampling frequencies (>20 sps). Due to the apparent temperature dependence of this glitch pattern we currently favor the possibility that they are produced by the temperature decrease resulting in slight contractions of the tether and/or Load Shunt Assembly (LSA)—located both at azimuths ≈15° and connecting SEIS with the InSight lander.…”

“…To date, all six seismic components as well as the acquisition system have functioned nominally, exceeded mission requirements, and delivered unprecedented seismic data from the surface of Mars (InSight Mars SEIS Data Service, 2019). In addition to seismic signals of natural and artificial origins, that is, marsquakes (Lognonné et al, 2020; Giardini et al, 2020; Clinton et al, 2020; InSight Marsquake Service, 2020 for event catalog) and records from the HP 3 instrument hammering sessions (Spohn et al., 2018), respectively, these data show a variety of nonseismic signals (Ceylan et al, 2020). Among the most prominent and abundant types of these nonseismic signals are what we termed a “glitch”.…”

Super High Frequency Events: A New Class of Events Recorded by the InSight Seismometers on Mars

“…We use the VBB sensor output in velocity following the overall gain removal and rotation to ZNE. Although SF events are equally visible in 20 sps VBB and SP recordings, the VBB sensor is preferred over the SP sensor (67.SH[UVW]) due to the completeness of the data set (data availability is shown in Figure 2 of Ceylan et al., 2020).…”

“…These are summarized in Ceylan et al. (2020), together with the availability of the seismic and nonseismic channels during the mission.…”

High‐Frequency Seismic Events on Mars Observed by InSight

“…The spectrogram shown for Sol 421 shows typical seismic background noise sources for a martian sol and is representative for the time period considered in this paper. The most obvious source for seismic noise is the martian atmosphere, notably wind and pressure fluctuations and their coupling to the InSight lander observed during the sunlit portion of the day (Ceylan et al., 2020; Lognonné et al., 2020). Sol 421 also exhibits bursts of energy visible across a broad band of frequencies that are manifested as vertical bright‐colored lines in Figure 1; these are glitches (Scholz et al., 2020; Lognonné et al., 2020, SI5) that are caused by thermally induced events within the SEIS instrument assembly resulting in a small tilt of the seismometers.…”