The instrument package SEIS (Seismic Experiment for Internal Structure) with the three very broadband and three short-period seismic sensors is installed on the surface on Mars as part of NASA’s InSight Discovery 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. One ubiquitous artifact in the raw data is an abundance of transient one-sided pulses often accompanied by high-frequency spikes. 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 SEIS-internal stress relaxations caused by the large temperature variations to which the instrument is exposed during a Martian day. Only a small fraction of glitches correspond to a motion of the SEIS package as a whole caused by minuscule tilts of either the instrument or the ground. In this study, we focus on the analysis of the glitch+spike phenomenon and present how these signals can be automatically detected and removed from SEIS’ raw data. As glitches affect many standard seismological analysis methods such as receiver functions, spectral decomposition and source inversions, we anticipate that studies of the Martian seismicity as well as studies of Mars’ internal structure should benefit from deglitched seismic data.

Seismic observations involve signals that can be easily masked by noise injection. For InSight, NASA's lander on Mars, the atmosphere is a significant noise contributor for two thirds of a Martian day, and while the noise is below that seen at even the quietest sites on Earth, the amplitude of seismic signals on Mars is also considerably lower requiring an understanding and quantification of environmental injection at unprecedented levels. Mars' ground and atmosphere provide a continuous coupled seismic system, and although atmospheric functions are of distinct origins, the superposition of these noise contributions is poorly understood, making separation a challenging task. We present a novel method for partitioning the observed signal into seismic and environmental contributions. Pressure and wind fluctuations are shown to exhibit temporal cross-frequency coupling across multiple bands, injecting noise that is neither random nor coherent. We investigate this through comodulation, quantifying the signal synchrony in seismic motion, wind and pressure. By working in the time-frequency domain, we discriminate the origins of underlying processes and provide the site's environmental sensitivity. Our method aims to create a virtual vault at InSight, shielding the seismometers with effective post-processing in lieu of a physical vault. This allows us to describe the environmental and seismic signals over a sequence of sols, to quantify the wind and pressure injection, and estimate the seismic content of possible Marsquakes with a signal-to-noise ratio that can be quantified in terms of environmental independence. Finally, we exploit the temporal energy correlations for source attribution of our observations.

Orbital and surface observations demonstrate that aeolian activity is occurring on Mars. Here we report the aeolian changes observed in situ by NASA's InSight lander during the first 400 sols of operations. Aeolian changes include creep of grains with diameters of up to 3 mm, dust removal, dark trails left by passing vortices and possible saltation. InSight has observed such changes by using, for the first time, simultaneous imaging and continuous, high-frequency meteorological, seismological, and magnetic measurements. We show that this multi-instrument combination constrains both the timing, and specific atmospheric conditions during which, aeolian changes occur. The observed changes are infrequent and episodic, consistently occur between noon and 3 pm, and are systematically associated with the passage of convective vortices. The sudden onset of peak vortex wind speeds promotes particle motion during sequences of enhanced vortex activity and stronger ambient winds. Aeolian changes are correlated with excursions in ground acceleration and magnetic field strength, suggesting vortex-induced ground deformation and charged-particle motion.