P055-0006
InSight seismic data from Mars: Effect and treatment of transient data disturbances
Monday, 14 December 2020
Poster
Rudolf Widmer-Schnidrig1, John-Robert Scholz2, Paul Davis3, Philippe Henri Lognonné4, Baptiste Pinot5, Raphael Garcia6, Kenneth J Hurst7, Laurent Pou8, Francis Nimmo9, Salma Barkaoui10, Sebastien De Raucourt4, Brigitte Knapmeyer-Endrun11, Martin Knapmeyer12, Guenolé Orhand-Mainsant5, Nicolas Compaire5, Arthur Cuvier13, Eric Beucler14, Mickael J. A. Bonnin15, Rakshit Joshi16, Grégory Sainton10, Eleonore Stutzmann4, Martin Schimmel17, Anna C Horleston18, Maren Böse19, Savas Ceylan20, John F Clinton19, Martin van Driel21, Taichi Kawamura22, Amir Khan21, Simon C Staehler20, Domenico Giardini23, Constantinos Charalambous24, Alexander Stott25, William T Pike25, Ulrich R Christensen26 and William Bruce Banerdt27, (1)Black Forest Observatory, Wolfach, Germany, (2)Max Planck Institute for Solar System Research, Göttingen, Germany, (3)University of California, Los Angeles, Department of Earth, Planetary, and Space Sciences, Los Angeles, CA, United States, (4)Université de Paris, Institut de physique du globe de Paris, CNRS, Paris, France, (5)Institut Supérieur de l'Aéronautique et de l'Espace, Toulouse Cedex 04, France, (6)Institut Supérieur de l'Aéronautique et de l'Espace, DEOS/SSPA, Toulouse Cedex 04, France, (7)Jet Propulsion Lab / Caltech, Pasadena, CA, United States, (8)University of California Santa Cruz, Earth and Planetary Sciences, Santa Cruz, CA, United States, (9)University of California-Santa Cruz, Earth and Planetary Sciences, Santa Cruz, CA, United States, (10)Université de Paris, Institut de physique du globe de Paris, CNRS, F-75005 Paris, France, Planetology and space science, Paris, France, (11)University of Cologne, Bensberg Observatory, Cologne, Germany, (12)DLR-Inst Planetary Research, Berlin, Germany, (13)Laboratoire de planétologie et géodynamique, Université de Nantes, Nantes, France, (14)University of Nantes, Nantes, France, (15)GeoAzur, Valbonne, France, (16)Max Planck Institute for Solar System Research, Goettingen, Germany, (17)Geosciences Barcelona, CSIC, Barcelona, Spain, (18)University of Bristol, Bristol, United Kingdom, (19)ETH Swiss Federal Institute of Technology Zurich, Swiss Seismological Service (SED), Zurich, Switzerland, (20)ETH Zurich, Zurich, Switzerland, (21)ETH Zurich, Department of Earth Sciences, Institute of Geophysics, Zurich, Switzerland, (22)Université de Paris, Institut de physique du globe de Paris, Paris, France, (23)Swiss Federal Institute of Technology (ETH), Zurich, Switzerland, (24)Imperial College London, London, SW7, United Kingdom, (25)Imperial College London, London, United Kingdom, (26)Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany, (27)JPL/NASA/Caltech, Pasadena, CA, United States
Abstract:
The instrument package SEIS (
Seismic
Experiment for
Internal
Structure) with the two co-located seismometers VBB and SP is installed on the surface of Mars as part of NASA's
InSight 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. The daily atmospheric temperature variations of approx. 80K are attenuated by different insulation layers to approx. 15K peak-to-peak at the sensor level. Typical wind speeds vary between 0 and 5 m/s leading to a diurnal variation in the broad-band
rms noise level by two orders of magnitude. One ubiquitous artifact in the raw broad-band data is an abundance of one-sided, transient pulses often accompanied by high-frequency spikes. We show that 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 intermittent stress relaxation events internal to SEIS caused by the large diurnal temperature variations to which the instrument is exposed during a Martian sol. Only a small fraction of glitches correspond to a motion of the SEIS package as a whole caused by minuscule tilts of the instrument. Whilst such kind of data disturbances are typically discarded when occurring in terrestrial data, this is no option for the data returned from the Red Planet. We therefore do not only demonstrate their effects on the seismic data and analyze their origins, but also propose algorithms that are able to detect and remove many of these (mostly) non-seismic signals. We further published our codes (both Python and MATLAB) so that interested researchers can make their own choices on how to treat the data and to which extent.
