144 results found
Stott AE, Charalambous C, Warren TJ, et al., 2021, The Site Tilt and Lander Transfer Function from the Short-Period Seismometer of InSight on Mars, Bulletin of the Seismological Society of America, Vol: 111, Pages: 2889-2908, ISSN: 0037-1106
<jats:title>ABSTRACT</jats:title> <jats:p>The National Aeronautics and Space Administration InSight mission has deployed the seismic experiment, SEIS, on the surface of Mars, and has recorded a variety of signals including marsquakes and dust devils. This work presents results on the tilt and local noise sources, which provide context to aid interpretation of the observed signals and allow an examination of the near-surface properties. Our analysis uses data recorded by the short-period sensors on the deck, throughout deployment and in the final configuration. We use thermal decorrelation to provide an estimate of the sol-to-sol tilt. This tilt is examined across deployment and over a Martian year. After each modification to the site, the tilt is seen to stabilize over 3–20 sols depending on the action, and the total change in tilt is &lt;0.035°. Long-term tilt over a Martian year is limited to &lt;0.007°. We also investigate the attenuation of lander-induced vibrations between the lander and SEIS. Robotic arm motions provide a known lander source in the 5–9 Hz bandwidth, yielding an amplitude attenuation of lander signals between 100 and 1000 times. The attenuation of wind sensitivity from the deck to ground presents a similar value in the 1.5–9 Hz range, thus favoring a noise dominated by lander vibrations induced by the wind. Wind sensitivities outside this bandwidth exhibit different sensitivity changes, indicating a change in the coupling. The results are interpreted through a finite-element analysis of the regolith with a depth-dependent Young’s modulus. We argue that discrepancies between this model and the observations are due to local compaction beneath the lander legs and/or anelasticity. An estimate for the effective Young’s modulus is obtained as 62–81 MPa, corroborating previous estimates for the top layer duricrust.</jats:p>
<jats:title>ABSTRACT</jats:title> <jats:p>The Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) seismometer was deployed to the surface of Mars in December 2018–February 2019. The specific deployment conditions, which are very different from those of a standard broadband instrument on the Earth, result in resonances caused by different parts of the sensor assembly (SA) that are recorded by the seismometer. Here, we present and characterize the resonances known to be present in the SA and their causes to aid interpretation of the seismic signals observed on Mars. Briefly, there are resonances in the SA at about 2.9, 5.3, 9.5, 12, 14, 23–28, and 51 Hz. We discuss various methods and tests that were used to characterize these resonances, and provide evidence for some of them in data collected on Mars. In addition to their relevance for the high frequency analysis of seismic data from InSight, specifically for phase measurements near the resonant frequencies, the tests and observations described here are also of potential use in the further development of planetary seismometers, for example, for Mars, the Moon, or Europa.</jats:p>
Sollberger D, Schmelzbach C, Andersson F, et al., 2021, A Reconstruction Algorithm for Temporally Aliased Seismic Signals Recorded by the InSight Mars Lander., Earth Space Sci, Vol: 8, ISSN: 2333-5084
In December 2018, the NASA InSight lander successfully placed a seismometer on the surface of Mars. Alongside, a hammering device was deployed at the landing site that penetrated into the ground to attempt the first measurements of the planetary heat flow of Mars. The hammering of the heat probe generated repeated seismic signals that were registered by the seismometer and can potentially be used to image the shallow subsurface just below the lander. However, the broad frequency content of the seismic signals generated by the hammering extends beyond the Nyquist frequency governed by the seismometer's sampling rate of 100 samples per second. Here, we propose an algorithm to reconstruct the seismic signals beyond the classical sampling limits. We exploit the structure in the data due to thousands of repeated, only gradually varying hammering signals as the heat probe slowly penetrates into the ground. In addition, we make use of the fact that repeated hammering signals are sub-sampled differently due to the unsynchronized timing between the hammer strikes and the seismometer recordings. This allows us to reconstruct signals beyond the classical Nyquist frequency limit by enforcing a sparsity constraint on the signal in a modified Radon transform domain. In addition, the proposed method reduces uncorrelated noise in the recorded data. Using both synthetic data and actual data recorded on Mars, we show how the proposed algorithm can be used to reconstruct the high-frequency hammering signal at very high resolution.
Khan A, Ceylan S, van Driel M, et al., 2021, Upper mantle structure of Mars from InSight seismic data, SCIENCE, Vol: 373, Pages: 434-+, ISSN: 0036-8075
Charalambous C, McClean JB, Baker M, et al., 2021, Vortex-Dominated Aeolian Activity at InSight's Landing Site, Part 1: Multi-Instrument Observations, Analysis, and Implications, JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS, Vol: 126, ISSN: 2169-9097
Compaire N, Margerin L, Garcia RF, et al., 2021, Autocorrelation of the Ground Vibrations Recorded by the SEIS-InSight Seismometer on Mars, JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS, Vol: 126, ISSN: 2169-9097
Charalambous C, Stott AE, Pike WT, et al., 2021, A Comodulation Analysis of Atmospheric Energy Injection Into the Ground Motion at InSight, Mars, JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS, Vol: 126, ISSN: 2169-9097
Dahmen NL, Clinton JF, Ceylan S, et al., 2021, Super High Frequency Events: A New Class of Events Recorded by the InSight Seismometers on Mars, JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS, Vol: 126, ISSN: 2169-9097
van Driel M, Ceylan S, Clinton JF, et al., 2021, High-Frequency Seismic Events on Mars Observed by InSight, JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS, Vol: 126, ISSN: 2169-9097
Nunn C, Pike WT, Standley IM, et al., 2021, Standing on Apollo’s shoulders: A microseismometer for the moon, Planetary Science Journal, Vol: 2
Seismometers deployed on the Moon by the Apollo astronauts from 1969 to 1972 detected moonquakes and impacts, and added to our understanding of the lunar interior. Several lunar missions are currently being planned, including the Commercial Lunar Payload Services (CLPS), the Lunar Geophysical Network, and the astronaut program Artemis. We propose a microseismometer for the Moon: the Silicon Seismic Package (SSP). The SSP’s sensors are etched in silicon, and are predicted to have a noise floor below 2 ´ 10-10 (m s-2) Hz between 0.3 and 3 Hz (similar to the Apollo instruments between 0.3 and 0.5 Hz, and better than Apollo above 0.5 Hz). The SSP will measure horizontal and vertical motion with the three sensors in a triaxial configuration. The instrument is robust to high shock and vibration and has an operational range from -80°C to +60°C, allowing deployment under harsh conditions. The first-generation version of this sensor, the SEIS-SP, was deployed on Mars in 2018 as part of the InSight mission’s seismic package. We will reconfigure the seismometer for the lower gravity of the Moon. We estimate that a single SSP instrument operating for one year would detect around 74 events above a signal-to-noise ratio of 2.5, as well as an additional 500+ above the noise floor. A mission lasting from lunar dawn until dusk, carried on a CLPS lander, could test the instrument in situ, and provide invaluable information for an extensive future network.
Ceylan S, Clinton JF, Giardini D, et al., 2021, Companion guide to the marsquake catalog from InSight, Sols 0-478: Data content and non-seismic events, PHYSICS OF THE EARTH AND PLANETARY INTERIORS, Vol: 310, ISSN: 0031-9201
Scholz J-R, Widmer-Schnidrig R, Davis P, et al., 2020, Detection, Analysis, and Removal of Glitches From InSight's Seismic Data From Mars, EARTH AND SPACE SCIENCE, Vol: 7
McClean JB, Merrison JP, Iversen JJ, et al., 2020, Filtration of simulated Martian atmosphere for in-situ oxygen production, PLANETARY AND SPACE SCIENCE, Vol: 191, ISSN: 0032-0633
Weitz CM, Grant JA, Golombek MP, et al., 2020, Comparison of InSight Homestead Hollow to Hollows at the Spirit Landing Site, JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS, Vol: 125, ISSN: 2169-9097
Panning MP, Pike WT, Lognonne P, et al., 2020, On-Deck Seismology: Lessons from InSight for Future Planetary Seismology, JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS, Vol: 125, ISSN: 2169-9097
Grant JA, Warner NH, Weitz CM, et al., 2020, Degradation of Homestead Hollow at the InSight Landing Site Based on the Distribution and Properties of Local Deposits, JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS, Vol: 125, ISSN: 2169-9097
Lognonne P, Banerdt WB, Pike WT, et al., 2020, Constraints on the shallow elastic and anelastic structure of Mars from InSight seismic data, NATURE GEOSCIENCE, Vol: 13, Pages: 213-+, ISSN: 1752-0894
NASA’s InSight (Interior exploration using Seismic Investigations, Geodesy and Heat Transport) mission landed in Elysium Planitia on Mars on 26 November 2018. It aims to determine the interior structure, composition and thermal state of Mars, as well as constrain present-day seismicity and impact cratering rates. Such information is key to understanding the differentiation and subsequent thermal evolution of Mars, and thus the forces that shape the planet’s surface geology and volatile processes. Here we report an overview of the first ten months of geophysical observations by InSight. As of 30 September 2019, 174 seismic events have been recorded by the lander’s seismometer, including over 20 events of moment magnitude Mw = 3–4. The detections thus far are consistent with tectonic origins, with no impact-induced seismicity yet observed, and indicate a seismically active planet. An assessment of these detections suggests that the frequency of global seismic events below approximately Mw = 3 is similar to that of terrestrial intraplate seismic activity, but there are fewer larger quakes; no quakes exceeding Mw = 4 have been observed. The lander’s other instruments—two cameras, atmospheric pressure, temperature and wind sensors, a magnetometer and a radiometer—have yielded much more than the intended supporting data for seismometer noise characterization: magnetic field measurements indicate a local magnetic field that is ten-times stronger than orbital estimates and meteorological measurements reveal a more dynamic atmosphere than expected, hosting baroclinic and gravity waves and convective vortices. With the mission due to last for an entire Martian year or longer, these results will be built on by further measurements by the InSight lander.
Brinkman N, Schmelzbach C, Sollberger D, et al., 2020, The first active seismic experiment on Mars to characterize the shallow subsurface structure at the InSight landing site, Pages: 4756-4760
In November 2018, the InSight lander successfully touched down in the Elysium Planitia plain on Mars. Since then, two scientific instruments were deployed directly onto the surface of Mars: (1) SEIS, a package consisting of two three-component seismic sensors and (2) HP3, the heat flow and physical properties package. HP3 includes a self-hammering penetrator (mole) that hammers itself into the subsurface of Mars to a maximum depth of five meters. The mole hammering generates seismic signals that are recorded by SEIS and can be used to image the shallow subsurface just below the landing site. Even though not included in the level-one mission's objectives, this opportunistic seismic experiment is, to the best of our knowledge, the first active seismic experiment ever conducted on a different planet. Here, we discuss the most important aspects of the implementations of this opportunistic experiment.
Liu H, Pike WT, Charalambous C, et al., 2019, Passive Method for Reducing Temperature Sensitivity of a Microelectromechanical Seismic Accelerometer for Marsquake Monitoring Below 1 Nano-g, PHYSICAL REVIEW APPLIED, Vol: 12, ISSN: 2331-7019
Sollberger D, Garcia R, Giardini D, et al., 2019, Sparse Reconstruction of Aliased Seismic Signals Recorded during the Insight Mars Mission, Pages: 376-380
The NASA InSight lander successfully placed a seismometer on the surface of Mars. Alongside, a hammering device was deployed that penetrated into the ground to attempt the first measurements of the planetary heat flow of Mars. The hammering generated repeated seismic signals that were registered by the seismometer. These signals can potentially be used to image the shallow subsurface just below the lander. However, the frequencies excited by the hammering probe widely exceed the Nyquist frequency dictated by the seis-mometer's sampling rate. Here, we propose an algorithm to reconstruct the seismic signals beyond the classical sampling theorem. We exploit the structure in the data due to thousands of repeated, only gradually varying hammering signals as the heat probe slowly penetrates into the ground. This allows us to reconstruct signals by enforcing a sparsity constraint in a modified Radon transform domain.
Banfield D, Spiga A, Newman C, et al., 2019, Mars Atmospheric Science from NASA’s InSight Lander, Ninth International Conference on Mars
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