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1. Constraints on the shallow elastic and anelastic structure of Mars from InSight seismic data

Author

Lognonné, P., Banerdt, W. B., Pike, W. T., Giardini, D., Christensen, U., Garcia, R. F., Kawamura, T., Kedar, S., Knapmeyer-Endrun, B., Margerin, L., Nimmo, F., Panning, M., Tauzin, B., Scholz, J.-R., Antonangeli, D., Barkaoui, S., Beucler, E., Bissig, F., Brinkman, N., Calvet, M., Ceylan, S., Charalambous, C., Davis, P., van Driel, M., Drilleau, M., Fayon, L., Joshi, R., Kenda, B., Khan, A., Knapmeyer, M., Lekic, V., McClean, J., Mimoun, D., Murdoch, N., Pan, L., Perrin, C., Pinot, B., Pou, L., Menina, S., Rodriguez, S., Schmelzbach, C., Schmerr, N., Sollberger, D., Spiga, A., Stähler, S., Stott, A., Stutzmann, E., Tharimena, S., Widmer-Schnidrig, R., Andersson, F., Ansan, V., Beghein, C., Böse, M., Bozdag, E., Clinton, J., Daubar, I., Delage, P., Fuji, N., Golombek, M., Grott, M., Horleston, A., Hurst, K., Irving, J., Jacob, A., Knollenberg, J., Krasner, S., Krause, C., Lorenz, R., Michaut, C., Myhill, R., Nissen-Meyer, T., ten Pierick, J., Plesa, A.-C., Quantin-Nataf, C., Robertsson, J., Rochas, L., Schimmel, M., Smrekar, S., Spohn, T., Teanby, N., Tromp, J., Vallade, J., Verdier, N., Vrettos, C., Weber, R., Banfield, D., Barrett, E., Bierwirth, M., Calcutt, S., Compaire, N., Johnson, C.L., Mance, D., Euchner, F., Kerjean, L., Mainsant, G., Mocquet, A., Rodriguez Manfredi, J. A, Pont, G., Laudet, P., Nebut, T., de Raucourt, S., Robert, O., Russell, C. T., Sylvestre-Baron, A., Tillier, S., Warren, T., Wieczorek, M., Yana, C., and Zweifel, P.

Published
2020
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2. Results From Insight’s First Full Martian Year

Author

Wieczorek, M, Weber, R, Warner, N, Tromp, J, Teanby, N, Stanley, S, Stahler, S, Spohn, T, Spiga, A, Siegler, M, Schmerr, N, Rodriguez-Manfredi, P.J.A, Plesa, A.-C, Pike, W.T, Nimmo, Francis, Newman, C, Nagihara, S, Müller, N, Morgan, P, Mittelholz, A, Mimoun, D, Michaut, C, McLennan, S, Margerin, L, Maki, J, Lorenz, R, Lognonné, P, Lemmon, M, Knapmeyer-Endrun, B, King, S, Khan, A, Kedar, S, Kawamura, Taichi, Kargl, G, Joshi, R, Johnson, C, Irving, J, Hudson, T, Grygorczuk, J, Grott, M, Grant, J, Golombek, M, Giardini, D, Garvin, J, Garcia, R, Folkner, W, Fillingim, M, Dehant, V, Daubar, I, Collins, G, Clinton, J, Christensen, U, Chi, P, Ceylan, S, Brinkman, N, Bozdag, Ebru, Bowles, Neil, Bissig, F, Beucler, E, Beghein, C, Banfield, D, Asmar, S, Antonangeli, D, Smrekar, S, Banerdt, W. B, and Panning, M.P

Published
2021

3. Results From Insight’s First Full Martian Year

Author

Panning, M.P, Banerdt, W. B, Smrekar, S, Antonangeli, D, Asmar, S, Banfield, D, Beghein, C, Beucler, E, Bissig, F, Bowles, Neil, Bozdag, Ebru, Brinkman, N, Ceylan, S, Chi, P, Christensen, U, Clinton, J, Collins, G, Daubar, I, Dehant, V, Fillingim, M, Folkner, W, Garcia, R, Garvin, J, Giardini, D, Golombek, M, Grant, J, Grott, M, Grygorczuk, J, Hudson, T, Irving, J, Johnson, C, Joshi, R, Kargl, G, Kawamura, Taichi, Kedar, S, Khan, A, King, S, Knapmeyer-Endrun, B, Lemmon, M, Lognonné, P, Lorenz, R, Maki, J, Margerin, L, McLennan, S, Michaut, C, Mimoun, D, Mittelholz, A, Morgan, P, Müller, N, Nagihara, S, Newman, C, Nimmo, Francis, Pike, W.T, Plesa, A.-C, Rodriguez-Manfredi, P.J.A, Schmerr, N, Siegler, M, Spiga, A, Spohn, T, Stahler, S, Stanley, S, Teanby, N, Tromp, J, Warner, N, Weber, R, and Wieczorek, M

Published
2021

5. Joint inversion of PP and SS precursor waveforms and Rayleigh wave phase velocities for global mantle transition zone structure.

Author

Bissig, F, Khan, A, and Giardini, D

Subjects
*SURFACE waves (Seismic waves), *RAYLEIGH waves, *PHASE velocity, *SEISMIC wave velocity, *SUBDUCTION zones, *PHYSICS, *ELECTRONIC data processing
Abstract

We have compiled a new data set of global PP and SS precursor waveforms that we jointly invert in combination with fundamental-mode and higher-order Rayleigh-wave phase velocities for upper mantle and mantle transition zone (MTZ) structure. We observe clear S410S, S520S, S660S and P410P precursor arrivals, but not P660P, because of interfering phases. Traveltimes and amplitudes of precursor phases reflect a complex interplay of data and modelling factors, implying that MTZ structure is best resolved through direct inversion of waveforms. To model waveforms as accurately as possible, we account for effects arising from data processing, shallow structure, incoherent stacking, attenuation and source effects, among others. As part of the inversion, we consider two independent model parametrizations to obtain quantitative insights into the seismic and thermochemical constitution of the MTZ. These include a 'classical' seismic parametrization based on a layered seismic velocity structure and a thermodynamic parametrization, where seismic profiles are self-consistently built from mineral physics data. The results show lateral variations in thermal, compositional and discontinuity structure that partly correlate with tectonic setting. The mantle beneath continents and subduction zones is found to be colder in comparison to oceans and hotspots as reflected in MTZ thickness. In terms of composition, we find that subduction zones are enriched in basalt. Mid-MTZ structure shows a trend from simple sub-ocean single- to complex circum-Pacific subduction-zone-related dual-discontinuity structure—the possible signature of oceanic crustal transport to the MTZ. Statistical analysis indicates that a mechanically mixed mantle matches seismic data better than an equilibrated mantle across ∼2/3 of the globe. Finally, while a large part of the seismic data can be matched by an iso-chemical and adiabatic mantle, complexities within the MTZ are not entirely captured by this assumption. [ABSTRACT FROM AUTHOR]

Published
2023
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6. The interior of Mars as seen by InSight (Invited)

Author

Staehler, Simon C., Khan, A., Knapmeyer‐Endrun, Brigitte, Panning, Mark P., Banerdt, William B., Lognonné, P., Giardini, Domenico, Antonangeli, D., Beucler, E., Bissig, F., Bozdag, E., Brinkmann, N., Ceylan, S., Charalambous, C., Clinton, John F., Compaire, Nicolas, Dahmen, N. L., Davis, P., van Driel, M., Drilleau, M., Garcia, Raphael F., Huang, Quancheng, Joshi, Rakshit, Gudkova, T., Irving, Jessica C. E., Johnson, C., Kawamura, T., Kim, Doyeon, Knapmeyer, Martin, Maguire, R., Lekic, Vedran, Margerin, L., Marusiak, A, McLennan, S M, Mittelholz, A., Michaut, Chloe, Plasman, M., Pan, L., Duran, C., Perrin, C., Pike, T., Plesa, Ana-Catalina, Pinot, Baptiste, Rivoldini, A., Scholz, J.-R., Schimmel, Martin, Schmerr, N., Stutzmann, Éléonore, Samuel, H., Smrekar, S., Spohn, Tilman, Tauzin, B., Tharimena, S., Widmer-Schnidrig, R, Wieczorek, M., Xu, Zongbo, Zenhäusern, Geraldine, Karakostas, F., and InSight, Science Team

Abstract

InSight is the first planetary mission dedicated to exploring the whole interior of a planet using geophysical methods, specifically seismology and geodesy. To this end, we observed seismic waves of distant marsquakes and inverted for interior models using differential travel times of phases reflected at the surface (PP, SS...) or the core mantle-boundary (ScS), as well as those converted at crustal interfaces. Compared to previous orbital observations1-3, the seismic data added decisive new insights with consequences for the formation of Mars: The global average crustal thickness of 24-75 km is at the low end of pre-mission estimates5. Together with the the thick lithosphere of 450-600 km5, this requires an enrichment of heat-producing elements in the crust by a factor of 13-20, compared to the primitive mantle. The iron-rich liquid core is 1790-1870 km in radius6, which rules out the existence of an insulating bridgmanite-dominated lower mantle on Mars. The large, and therefore low-density core needs a high amount of light elements. Given the geochemical boundary conditions, Sulfur alone cannot explain the estimated density of ~6 g/cm3 and volatile elements, such as oxygen, carbon or hydrogen are needed in significant amounts. This observation is difficult to reconcile with classical models of late formation from the same material as Earth. We also give an overview of open questions after three years of InSight operation on the surface of Mars, such as the potential existence of an inner core or compositional layers above the CMB

Published
2021

7. Seismic Constraints on the Thickness and Structure of the Martian Crust from InSight

Author

California Institute of Technology, Panning, M., Knapmeyer‐Endrun, Brigitte, Bissig, F., Joshi, R., Khan, A., Kim, D., Lekic, Vedran, Tauzin, B., Tharimena, S., Plasman, M., Compaire, N., Garcia, R., Margerin, L., Schimmel, Martin, Stutzmann, E., Schmerr, N., Bozdag, E., Plesa, A. C., Wieczorek, M., Broquet, A., Antonangeli, D., McLennan, Scott M., Samuel, H., Michaut, C., Pan, L., Perrin , C., Smrekar, S., Johnson, C. L., Brinkmann, N., Mittelholz, A., Rivoldini, A., Davis, P., Lognonné, P., Pinot, B, Scholz, J. R., Stähler, S., Knapmeyer, M., van Driel, M., Giardini, Domenico, Banerdt, B., California Institute of Technology, Panning, M., Knapmeyer‐Endrun, Brigitte, Bissig, F., Joshi, R., Khan, A., Kim, D., Lekic, Vedran, Tauzin, B., Tharimena, S., Plasman, M., Compaire, N., Garcia, R., Margerin, L., Schimmel, Martin, Stutzmann, E., Schmerr, N., Bozdag, E., Plesa, A. C., Wieczorek, M., Broquet, A., Antonangeli, D., McLennan, Scott M., Samuel, H., Michaut, C., Pan, L., Perrin , C., Smrekar, S., Johnson, C. L., Brinkmann, N., Mittelholz, A., Rivoldini, A., Davis, P., Lognonné, P., Pinot, B, Scholz, J. R., Stähler, S., Knapmeyer, M., van Driel, M., Giardini, Domenico, and Banerdt, B.

Abstract

NASA¿s InSight mission [1] has for the first time placed a very broad-band seismometer on the surface of Mars. The Seismic Experiment for Interior Structure (SEIS) [2] has been collecting continuous data since early February 2019. The main focus of InSight is to enhance our understanding of the internal structure and dynamics of Mars, which includes the goal to better constrain the crustal thickness of the planet [3]. Knowing the present-day crustal thickness of Mars has important implications for its thermal evolution [4] as well as for the partitioning of silicates and heat-producing elements between the different layers of Mars. Current estimates for the crustal thickness of Mars are based on modeling the relationship between topography and gravity [5,6], but these studies rely on different assumptions, e.g. on the density of the crust and upper mantle, or the bulk silicate composition of the planet and the crust. The resulting values for the average crustal thickness differ by more than 100%, from 30 km to more than 100 km [7]. New independent constraints from InSight will be based on seismically determining the crustal thickness at the landing site. This single firm measurement of crustal thickness at one point on the planet will allow to constrain both the average crustal thickness of Mars as well as thickness variations across the planet when combined with constraints from gravity and topography [8]. Here we describe the determination of the crustal structure and thickness at the InSight landing site based on seismic receiver functions for three marsquakes compared with autocorrelations of InSight data [9].

Published
2021

8. Thickness and structure of the Martian crust from InSight seismic data

Author

California Institute of Technology, Swiss National Science Foundation, European Commission, NASA Astrobiology Institute (US), Canadian Space Agency, European Space Agency, Knapmeyer‐Endrun, Brigitte, Panning, M.P., Bissig, F., Joshi, R., Khan, A., Kim, D., Lekic, Vedran, Tauzin, B., Tharimena, S., Plasman, M., Compaire, N., Garcia, R. F., Margerin, L., Schimmel, Martin, Stutzmann, E., Schmerr, N., Bozdag, E., Plesa, A. C., Wieczorek, M. A., Broquet, A., Antonangeli, D., McLennan, Scott M., Samuel, H., Michaut, C., Pan, L., Smrekar, S. E., Johnson, C.L., Brinkman, N., Mittelholz, A., Rivoldini, A., Davis, P. M., Lognonné, P., Pinot, B, Scholz, J. R., Stahler, Simon, Knapmeyer, M., van Driel, M., Giardini, Domenico, Banerdt, W. B., California Institute of Technology, Swiss National Science Foundation, European Commission, NASA Astrobiology Institute (US), Canadian Space Agency, European Space Agency, Knapmeyer‐Endrun, Brigitte, Panning, M.P., Bissig, F., Joshi, R., Khan, A., Kim, D., Lekic, Vedran, Tauzin, B., Tharimena, S., Plasman, M., Compaire, N., Garcia, R. F., Margerin, L., Schimmel, Martin, Stutzmann, E., Schmerr, N., Bozdag, E., Plesa, A. C., Wieczorek, M. A., Broquet, A., Antonangeli, D., McLennan, Scott M., Samuel, H., Michaut, C., Pan, L., Smrekar, S. E., Johnson, C.L., Brinkman, N., Mittelholz, A., Rivoldini, A., Davis, P. M., Lognonné, P., Pinot, B, Scholz, J. R., Stahler, Simon, Knapmeyer, M., van Driel, M., Giardini, Domenico, and Banerdt, W. B.

Abstract

A planet's crust bears witness to the history of planetary formation and evolution, but for Mars, no absolute measurement of crustal thickness has been available. Here, we determine the structure of the crust beneath the InSight landing site on Mars using both marsquake recordings and the ambient wavefield. By analyzing seismic phases that are reflected and converted at subsurface interfaces, we find that the observations are consistent with models with at least two and possibly three interfaces. If the second interface is the boundary of the crust, the thickness is 20 +/- 5 kilometers, whereas if the third interface is the boundary, the thickness is 39 +/- 8 kilometers. Global maps of gravity and topography allow extrapolation of this point measurement to the whole planet, showing that the average thickness of the martian crust lies between 24 and 72 kilometers. Independent bulk composition and geodynamic constraints show that the thicker model is consistent with the abundances of crustal heat-producing elements observed for the shallow surface, whereas the thinner model requires greater concentration at depth.

Published
2021

9. First Receiver Functions on Mars - Constraints on the Martian Crust from InSight

Author

Knapmeyer‐Endrun, Brigitte, Bissig, F., Compaire, N., Joshi, R., Garcia, R., Khan, A., Kim, D., Lekic, Vedran, Margerine, L., Panning, M., Schimmel, Martin, Schmerr, N., Stutzmann, E., Tauzin, B., Tharimena, S., Bozdag, E., Peter, Daniel B., Plesa, A. C., Lognonné, P., Smrekar, S., and Nanerdt, W. B.

Subjects
Mars
Abstract

2020 SSA Annual Meeting, 27-30 April, Albuquerque, New Mexico, NASA¿s InSight mission has for the first time deployed a very broad-band seismometer, SEIS, on the surface of Mars, which has been collecting data continuously since early February 2019. The main focus of InSight is to enhance our understanding of the internal structure and dynamics of Mars, including better constraints on its crustal thickness. Various models based on topography and gravity observed from the orbit currently differ by more than 100% for the average crustal thickness. Here, we present P-to-S and S-to-P receiver functions, which are available for 4 and 3 marsquakes, respectively, up to now. All of these quakes are located at comparatively small epicentral distances, between 25° and 40°. We observe three consistent phases within the first 10 seconds of the P-to-S receiver functions. The S-to-P receiver functions also show a consistent first phase. Later arrivals are harder to pinpoint, which could be due to the comparatively shallow incidence of the S-waves at the considered distances, which prevents the generation of converted waves. To obtain better constraints on velocity, we also calculated apparent velocity curves from the P-to-S receiver functions, but these provide meaningful results for only one event so far, implying a large uncertainty. Due to difficulties in clearly identifying multiples, the receiver functions can currently be explained by either two crustal layers and a thin (25-30 km) crust or three crustal layers and a thicker (40-45 km) crust at the landing site. This model range already improves the present constraints by providing a new maximum value of less than 70 km instead of more than 100 km for the average crustal thickness. Information from noise autocorrelations as a complementary method, identification of P-reverberations and S-precursors in the event recordings and more extensive modeling, ultimately including 3D-effects, are investigated to tighten the constraints.

Published
2020

10. Seismic constraints on the crustal structure of Mars from InSight receiver functions

Author

Knapmeyer‐Endrun, Brigitte, Bissig, F., Compaire, R., Joshi, R., Garcia, R., Khan, A., Kim, D., Lekic, Vedran, Margerine, L., Panning, M., Schimmel, Martin, Schmerr, N., Stutzmann, E., Tauzin, B., Tharimena, S., Bozdag, E., Peter, Daniel B., Plesa, A. C., Lognonné, P., Smrekar, S., and Banerdt, W. B.

Abstract

51st Lunar and Planetary Science Conference (2020), 16 march, Texas, USA, NASA's InSight mission has for the first time placed a very broad-band seismometer on the surface of Mars. The Seismic Experiment for Inte-rior Structure (SEIS) has been collecting continuous data since early February 2019. The main focus of InSight is to enhance our understanding of the internal structure and dynamics of Mars, which includes the goal to better constrain the crustal thickness of the planet [1]. Knowing the present-day crustal thickness of Mars has important implications for its thermal evo-lution [2] as well as for the partitioning of silicates and heat-producing elements between the different layers of Mars. Current estimates for the crustal thickness of Mars are based on modeling the relationship between topography and gravity [3,4], but these studies rely on different assumptions, e.g. on the density of the crust and upper mantle, or the bulk silicate composition of the planet and the crust. The resulting values for the average crustal thickness differ by more than 100%, from 30 km to more than 100 km [5]. New constraints from InSight will be based on seismically determining the crustal thickness at the landing site. This single firm measurement of crustal thickness at one point on the planet will allow to con-strain both the average crustal thickness of Mars as well as thickness variations across the planet when combined with constraints from gravity and topogra-phy [6]. Here we describe the first constraints on the crustal structure and thickness at the InSight landing site based on seismic receiver functions for four marsquakes [7].

Published
2020

11. Constraints on the shallow elastic and anelastic structure of Mars from InSight seismic data

Author

Lognonné, P.; Banerdt, W.B.; Pike, W.T.; Giardini, D.; Christensen, U.; Garcia, R.F.; Kawamura, T.; Kedar, S.; Knapmeyer-Endrun, B.; Margerin, L.; Nimmo, F.; Panning, M.; Tauzin, B.; Scholz, J.R.; Antonangeli, D.; Barkaoui, S.; Beucler, E.; Bissig, F.; Brinkman, N.; Calvet, M.; Ceylan, S.; Charalambous, C.; Davis, P.; van Driel, M.; Drilleau, M.; Fayon, L.; Joshi, R.; Kenda, B.; Khan, A.; Knapmeyer, M.; Lekic, V.; McClean, J.; Mimoun, D.; Murdoch, N.; Pan, L.; Perrin, C.; Pinot, B.; Pou, L.; Menina, S.; Rodriguez, S.; Schmelzbach, C.; Schmerr, N.; Sollberger, D.; Spiga, A.; Stähler, S.; Stott, A.; Stutzmann, E.; Tharimena, S.; Widmer-Schnidrig, R.; Schimmel, M.; Rodriguez Manfredi, J.A. and Lognonné, P.; Banerdt, W.B.; Pike, W.T.; Giardini, D.; Christensen, U.; Garcia, R.F.; Kawamura, T.; Kedar, S.; Knapmeyer-Endrun, B.; Margerin, L.; Nimmo, F.; Panning, M.; Tauzin, B.; Scholz, J.R.; Antonangeli, D.; Barkaoui, S.; Beucler, E.; Bissig, F.; Brinkman, N.; Calvet, M.; Ceylan, S.; Charalambous, C.; Davis, P.; van Driel, M.; Drilleau, M.; Fayon, L.; Joshi, R.; Kenda, B.; Khan, A.; Knapmeyer, M.; Lekic, V.; McClean, J.; Mimoun, D.; Murdoch, N.; Pan, L.; Perrin, C.; Pinot, B.; Pou, L.; Menina, S.; Rodriguez, S.; Schmelzbach, C.; Schmerr, N.; Sollberger, D.; Spiga, A.; Stähler, S.; Stott, A.; Stutzmann, E.; Tharimena, S.; Widmer-Schnidrig, R.; Schimmel, M.; Rodriguez Manfredi, J.A.

Abstract

Mars’s seismic activity and noise have been monitored since January 2019 by the seismometer of the InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) lander. At night, Mars is extremely quiet; seismic noise is about 500 times lower than Earth’s microseismic noise at periods between 4 s and 30 s. The recorded seismic noise increases during the day due to ground deformations induced by convective atmospheric vortices and ground-transferred wind-generated lander noise. Here we constrain properties of the crust beneath InSight, using signals from atmospheric vortices and from the hammering of InSight’s Heat Flow and Physical Properties (HP) instrument, as well as the three largest Marsquakes detected as of September 2019. From receiver function analysis, we infer that the uppermost 8–11 km of the crust is highly altered and/or fractured. We measure the crustal diffusivity and intrinsic attenuation using multiscattering analysis and find that seismic attenuation is about three times larger than on the Moon, which suggests that the crust contains small amounts of volatiles.

Published
2020

12. New seismological constraints on the crustal structure of Mars and the Moon

Author

Knapmeyer‐Endrun, Brigitte, Panning, Mark P., Bissig, F., Joshi, Rakshit, Khan, A., Kim, Doyeon, Lekic, Vedran, Tauzin, Benoit, Tharimena, S., Plasman, Matthieu, Compaire, Nicolas, Garcia, Raphael F., Margerin, Ludovic, Schimmel, Martin, Stutzmann, E., Schmerr, Nicholas C., Antonangeli, D., Bozdag, E., McLennan, S., Peter, Daniel B., Plesa, A. C., Samuel, H., Wieczorek, M., Davis, Paul, Lognonné, P., Pinot, Baptiste, Scholz, J. R., Staehler, Simon C., Knapmeyer, M., Brinkman, N., van Driel, M., Giardini, Domenico, Johnson, C., Smrekar, S. E., Banerdt, William B., Knapmeyer‐Endrun, Brigitte, Panning, Mark P., Bissig, F., Joshi, Rakshit, Khan, A., Kim, Doyeon, Lekic, Vedran, Tauzin, Benoit, Tharimena, S., Plasman, Matthieu, Compaire, Nicolas, Garcia, Raphael F., Margerin, Ludovic, Schimmel, Martin, Stutzmann, E., Schmerr, Nicholas C., Antonangeli, D., Bozdag, E., McLennan, S., Peter, Daniel B., Plesa, A. C., Samuel, H., Wieczorek, M., Davis, Paul, Lognonné, P., Pinot, Baptiste, Scholz, J. R., Staehler, Simon C., Knapmeyer, M., Brinkman, N., van Driel, M., Giardini, Domenico, Johnson, C., Smrekar, S. E., and Banerdt, William B.

Abstract

Planetary crusts are the results of mantle differentiation, so their thickness provides important constraints on the thermochemical evolution of a planet, including its heat budget and mantle rheology. Information on crustal layering and seismic velocities can also provide important constraints on porosity and geochemistry of the crust. Here, we use data from the InSight mission, which landed in November 2018, to provide seismological constraints on the crustal layering and thickness of Mars for the first time. Results are mainly based on Ps-receiver functions from three events with magnitudes between 3.1 and 3.6 at distances between 27.5° and 47° (±10°) from the lander, originating in the Cerberus Fossae region, the only events, so far, with clear, impulsive P-wave onsets and known epicenter. Ps-receiver functions use converted phases in the P-wave coda to derive information on discontinuities beneath the seismometer. Due to the limited number of events and the small epicentral distance range covered, inversions of the data are still ambiguous. Two sets of models can explain the waveforms, one consisting of a two-layer crust of about 20 to 23 km thickness, the other having a three-layer crust of about 40 to 45 km thickness. By excluding crustal thicknesses in excess of 45 km at the landing site, we can constrain the global average crustal thickness of Mars to be less than 70 km. Both model types also agree with S-receiver functions for two events and seismic P-waves reflected in the crust and extracted from autocorrelations using the coda of different types of marsquakes as well as the background wavefield. Furthermore, the results are compatible with independently conducted moment tensor inversions for a limited number of events as well as modeling of the wave-propagation of high-frequency events. We find low seismic P-wave velocities below 3.4 km/s within the upper approximately 10 km, likely indicating a high porosity. For the Moon, we present Sp-receiver functi

Published
2020

13. First seismic constraints on the Martian crust - receiver functions for InSight

Author

Knapmeyer‐Endrun, Brigitte, Bissig, F., Compaire, Nicolas, García, Raphael, Joshi, Rakshit, Khan, A., Kim, Doyeon, Lekic, Vedran, Margerin, Ludovic, Panning, M., Schimmel, Martin, Schmerr, N., Stutzmann, E., Tauzin, Benoit, Tharimena, S., Stähler, S., Davis, Paul, Pinot, Baptiste, Scholz, J. R., the InSight crustal structure team, Knapmeyer‐Endrun, Brigitte, Bissig, F., Compaire, Nicolas, García, Raphael, Joshi, Rakshit, Khan, A., Kim, Doyeon, Lekic, Vedran, Margerin, Ludovic, Panning, M., Schimmel, Martin, Schmerr, N., Stutzmann, E., Tauzin, Benoit, Tharimena, S., Stähler, S., Davis, Paul, Pinot, Baptiste, Scholz, J. R., and the InSight crustal structure team

Abstract

NASA's InSight mission arrived on Mars in November 2018 and deployed the first very broad-band seismometer, SEIS, on the planet's surface. SEIS has been collecting data continuously since early February 2019, by now recording more than 400 events of different types. InSight aims at enhancing our understanding of the internal structure and dynamics of Mars, including better constraints on its crustal thickness. Various models based on topography and gravity observed from the orbit currently vary in average crustal thickness from 30 km to more than 100 km, with important implications for Mars¿ thermal evolution, and the partitioning of silicates and heat-producing elements between different layers of Mars. We present P-to-S and S-to-P receiver functions, which are available for 4 and 3 marsquakes, respectively, up to now. Out of all of the marsquakes recorded to date, these are the only ones with clear enough P- or S-arrivals not dominated by scattering to make them suitable for the analysis. All of the quakes are located at comparatively small epicentral distances, between 25° and 40°. We observe three consistent phases within the first 10 seconds of the P-to-S receiver functions. The S-to-P receiver functions also show a consistent first phase. Later arrivals are harder to pinpoint, which could be due to the comparatively shallow incidence of the S-waves at the considered distances, which prevents the generation of converted waves. Identification of later multiple phases in the P-to-S receiver functions likewise remains inconclusive. To obtain better constraints on velocity, we also calculated apparent velocity curves from the P-to-S receiver functions, but these provide meaningful results for only one event so far, implying a large uncertainty. Due to difficulties in clearly identifying multiples, the receiver functions can currently be explained by either two crustal layers and a thin (25-30 km) crust or three crustal layers and a thicker (40-45 km) crust at the l

Published
2020

14. Constraints on the shallow elastic and anelastic structure of Mars from InSight seismic data

Author

Centre National D'Etudes Spatiales (France), California Institute of Technology, NASA Astrobiology Institute (US), Swiss National Science Foundation, European Commission, Schimmel, Martin [0000-0003-2601-4462], Lognonné, P., Banerdt, W. B., Pike, William T., Giardini, Domenico, Christensen, U., Garcia, R. F., Kawamura, T., Kedar, S., Knapmeyer‐Endrun, Brigitte, Margerin, L., Nimmo, F., Daubar, I., Delage, P., Fuji, N., Golombek, M., Grott, M., Horleston, A., Hurst, K., Irving, J., Jacob, A., Knollenberg, J., Krasner, S., Krause, C., Lorenz, R., Michaut, C., Myhill, Robert, Nissen-Meyer, T., ten Pierick, J., Plesa, A. C., Quantin-Nataf, C., Robertsson, J., Rochas, L., Schimmel, Martin, Smrekar, S., Spohn, T., Teanby, N., Tromp, J., Vallade, J., Verdier, N., Vrettos, C., Weber, R., Banfield, D., Barrett, E., Bierwirth, M., Calcutt, S., Compaire, N., Johnson, C. L., Mance, D., Euchner, F., Kerjean, L., Mainsant, G., Mocquet, A., Rodriguez Manfredi, J. A., Pont, G., Laudet, P., Nebut, T., de Raucourt, S., Robert, O., Russell, C. T., Sylvestre-Baron, A., Tillier, S., Warren, T., Wieczorek, M., Yana, C., Zweifel, P., Panning, M., Tauzin, B., Scholz, J. R., Antonangeli, D., Barkaoui, S., Beucler, E., Bissig, F., Brinkman, N., Calvet, M., Ceylan, S., Charalambous, C., Davis, P., van Driel, M., Drilleau, M., Fayon, L., Joshi, R., Kenda, B., Khan, A., Knapmeyer, M., Lekic, Vedran, McClean, J., Mimoun, D., Murdoch, N., Pan, L., Perrin , C., Pinot, B, Pou, L., Menina, S., Rodríguez, S., Schmelzbach, C., Schmerr, N., Sollberger, D., Spiga, A., Stähler, S., Stott, A., Stutzmann, E., Tharimena, S., Widmer-Schnidrig, R., Andersson, F., Ansan, V., Beghein, C., Böse, M., Bozdag, E., Clinton, John F., Centre National D'Etudes Spatiales (France), California Institute of Technology, NASA Astrobiology Institute (US), Swiss National Science Foundation, European Commission, Schimmel, Martin [0000-0003-2601-4462], Lognonné, P., Banerdt, W. B., Pike, William T., Giardini, Domenico, Christensen, U., Garcia, R. F., Kawamura, T., Kedar, S., Knapmeyer‐Endrun, Brigitte, Margerin, L., Nimmo, F., Daubar, I., Delage, P., Fuji, N., Golombek, M., Grott, M., Horleston, A., Hurst, K., Irving, J., Jacob, A., Knollenberg, J., Krasner, S., Krause, C., Lorenz, R., Michaut, C., Myhill, Robert, Nissen-Meyer, T., ten Pierick, J., Plesa, A. C., Quantin-Nataf, C., Robertsson, J., Rochas, L., Schimmel, Martin, Smrekar, S., Spohn, T., Teanby, N., Tromp, J., Vallade, J., Verdier, N., Vrettos, C., Weber, R., Banfield, D., Barrett, E., Bierwirth, M., Calcutt, S., Compaire, N., Johnson, C. L., Mance, D., Euchner, F., Kerjean, L., Mainsant, G., Mocquet, A., Rodriguez Manfredi, J. A., Pont, G., Laudet, P., Nebut, T., de Raucourt, S., Robert, O., Russell, C. T., Sylvestre-Baron, A., Tillier, S., Warren, T., Wieczorek, M., Yana, C., Zweifel, P., Panning, M., Tauzin, B., Scholz, J. R., Antonangeli, D., Barkaoui, S., Beucler, E., Bissig, F., Brinkman, N., Calvet, M., Ceylan, S., Charalambous, C., Davis, P., van Driel, M., Drilleau, M., Fayon, L., Joshi, R., Kenda, B., Khan, A., Knapmeyer, M., Lekic, Vedran, McClean, J., Mimoun, D., Murdoch, N., Pan, L., Perrin , C., Pinot, B, Pou, L., Menina, S., Rodríguez, S., Schmelzbach, C., Schmerr, N., Sollberger, D., Spiga, A., Stähler, S., Stott, A., Stutzmann, E., Tharimena, S., Widmer-Schnidrig, R., Andersson, F., Ansan, V., Beghein, C., Böse, M., Bozdag, E., and Clinton, John F.

Abstract

Mars’s seismic activity and noise have been monitored since January 2019 by the seismometer of the InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) lander. At night, Mars is extremely quiet; seismic noise is about 500 times lower than Earth’s microseismic noise at periods between 4 s and 30 s. The recorded seismic noise increases during the day due to ground deformations induced by convective atmospheric vortices and ground-transferred wind-generated lander noise. Here we constrain properties of the crust beneath InSight, using signals from atmospheric vortices and from the hammering of InSight’s Heat Flow and Physical Properties (HP3) instrument, as well as the three largest Marsquakes detected as of September 2019. From receiver function analysis, we infer that the uppermost 8–11 km of the crust is highly altered and/or fractured. We measure the crustal diffusivity and intrinsic attenuation using multiscattering analysis and find that seismic attenuation is about three times larger than on the Moon, which suggests that the crust contains small amounts of volatiles.

Published
2020

15. Schwester oder Rivalinnen? Musik und Poesie in Gerard Manley Hopkins' Gedicht 'Henry Purcell'

Author

Bissig, Florian, Escher, Georg, Struzek-Krähenbühl, Franziska, Bissig, F ( Florian ), Escher, G ( Georg ), Struzek-Krähenbühl, F ( Franziska ), Kasper, Monika, Bissig, Florian, Escher, Georg, Struzek-Krähenbühl, Franziska, Bissig, F ( Florian ), Escher, G ( Georg ), Struzek-Krähenbühl, F ( Franziska ), and Kasper, Monika

Abstract

Im Sonett "Henry Purcell" sucht Gerard Manley Hopkins durch die Imitation musikalischer Techniken des barocken Komponisten nach Wegen, seine dichterische Sprache zu erweitern. Entgegen dem ersten Anschein geht es ihm aber nicht nur darum, der Musik nachzueifern, sondern auch um die Verwirklichung eines performativen Konzepts von Sinn und Bedeutung, mit dem er eine Überlegenheit der Dichtkunst über die Musik insinuiert.

Published
2012

16. Thickness and structure of the martian crust from InSight seismic data.

Author

Knapmeyer-Endrun B, Panning MP, Bissig F, Joshi R, Khan A, Kim D, Lekić V, Tauzin B, Tharimena S, Plasman M, Compaire N, Garcia RF, Margerin L, Schimmel M, Stutzmann É, Schmerr N, Bozdağ E, Plesa AC, Wieczorek MA, Broquet A, Antonangeli D, McLennan SM, Samuel H, Michaut C, Pan L, Smrekar SE, Johnson CL, Brinkman N, Mittelholz A, Rivoldini A, Davis PM, Lognonné P, Pinot B, Scholz JR, Stähler S, Knapmeyer M, van Driel M, Giardini D, and Banerdt WB

Abstract

A planet's crust bears witness to the history of planetary formation and evolution, but for Mars, no absolute measurement of crustal thickness has been available. Here, we determine the structure of the crust beneath the InSight landing site on Mars using both marsquake recordings and the ambient wavefield. By analyzing seismic phases that are reflected and converted at subsurface interfaces, we find that the observations are consistent with models with at least two and possibly three interfaces. If the second interface is the boundary of the crust, the thickness is 20 ± 5 kilometers, whereas if the third interface is the boundary, the thickness is 39 ± 8 kilometers. Global maps of gravity and topography allow extrapolation of this point measurement to the whole planet, showing that the average thickness of the martian crust lies between 24 and 72 kilometers. Independent bulk composition and geodynamic constraints show that the thicker model is consistent with the abundances of crustal heat-producing elements observed for the shallow surface, whereas the thinner model requires greater concentration at depth., (Copyright © 2021 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)

Published
2021
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