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2. Phase statistics of seismic coda waves

Author

Anache-Ménier, D., Margerin, L., and van Tiggelen, B. A.

Subjects
Physics - Geophysics
Abstract

We report the analysis of the statistics of the phase fluctuations in the coda of earthquakes recorded during a temporary experiment deployed at Pinyon Flats Observatory, California. The practical measurement of the phase is discussed and the main pitfalls are underlined. For large values, the experimental distributions of the phase first, second and third derivatives obey universal power-law decays whose exponents are remarkably well predicted by circular Gaussian statistics. For small values, these distributions are flat. The details of the transition between the plateau and the power-law behavior are governed by the wavelength. The correlation function of the first phase derivative along the array shows a simple algebro-exponential decay with the mean free path as the only length scale. Although only loose bounds are provided in this study, our work suggests a new method to estimate the degree of heterogeneity of the cr, Comment: 4 figures, submitted to Physical Review Letters

Published
2008
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3. Observation of Weak Localization of Seismic Waves

Author

Larose, E., Margerin, L., van Tiggelen, B. A., and Campillo, M.

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics, Condensed Matter - Disordered Systems and Neural Networks
Abstract

We report the observation of weak localization of seismic waves in a natural environment. It emerges as a doubling of the seismic energy around the source within a spot of width a wavelength, that is several tens of meters in our case. The characteristic time for its onset is the scattering mean free time, that quantifies the internal heterogeneity., Comment: 4 pages

Published
2004

4. Stratification of Heterogeneity in the Lithosphere of Mars From Envelope Modeling of Event S1222a and Near Impacts: Interpretation and Implications for Very‐High‐Frequency Events

Author

Menina, S., primary, Margerin, L., additional, Kawamura, T., additional, Heller, G., additional, Drilleau, M., additional, Xu, Z., additional, Calvet, M., additional, Garcia, R. F., additional, Knapmeyer‐Endrun, B., additional, Carrasco, S., additional, Onodera, K., additional, Lognonné, P., additional, Stott, A., additional, and Banerdt, W. B., additional

Published
2023
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5. A Cerberus Fossae Seismic Network

Author

Stahler, S. C., Panning, Mark P., Antonangeli, D., Banerdt, W. B., Banks, M., Ceylan, S., Charalambous, C., Clinton, John, Daubar, I., Fernando, B., Giardini, Domenico, Grott, M., Horleston, A., Hurst, K., Kawamura, T., Khan, A., Kim, D., Knapmeyer, M., Knapmeyer-Endrun, Brigitte, Lorenz, L., Margerin, L., Marusiak, A, Menina, S., Mittelholz, A., Murdoch, N., Nishikawa, Y., Nunn, C., Perrin, C., Pike, William T., Schmelzbach, C., Schmerr, N., Schimmel, Martin, Spiga, A., Stott, A., Taylor, J., Weber, R., Stahler, S. C., Panning, Mark P., Antonangeli, D., Banerdt, W. B., Banks, M., Ceylan, S., Charalambous, C., Clinton, John, Daubar, I., Fernando, B., Giardini, Domenico, Grott, M., Horleston, A., Hurst, K., Kawamura, T., Khan, A., Kim, D., Knapmeyer, M., Knapmeyer-Endrun, Brigitte, Lorenz, L., Margerin, L., Marusiak, A, Menina, S., Mittelholz, A., Murdoch, N., Nishikawa, Y., Nunn, C., Perrin, C., Pike, William T., Schmelzbach, C., Schmerr, N., Schimmel, Martin, Spiga, A., Stott, A., Taylor, J., and Weber, R.

Abstract

Scientific Rationale: It is by now widely accepted that Mars had a wet and periodically warm past in the Noachian e.g. [1], but it is still open whether liquid water has played any role geologically in recent times or is even present in significant amounts near the surface today e.g. [2]. One key young area are the Cerberus Fossae (C.F.), a system of < 10 Ma old, 1200 km long grabens in Eastern Elysium Planitia. They connect to sediments in Athabasca Valles that have been interpreted as fluvial sediments from a frozen water layer molten by volcanism 8-10 Ma ago [3], but could alternatively be explained by very low viscosity lava as well [4]

Published
2023

6. Constraints for the Martian Crustal Structure From Rayleigh Waves Ellipticity of Large Seismic Events

Author

Carrasco, S., Knapmeyer-Endrun, Brigitte, Margerin, L., Xu, Z., Joshi, R., Schimmel, Martin, Stutzmann, Eleonore, Charalambous, C., Lognonné, P., Banerdt, W. B., Carrasco, S., Knapmeyer-Endrun, Brigitte, Margerin, L., Xu, Z., Joshi, R., Schimmel, Martin, Stutzmann, Eleonore, Charalambous, C., Lognonné, P., and Banerdt, W. B.

Abstract

For the first time, we measured the ellipticity of direct Rayleigh waves at intermediate periods (15–35 s) on Mars using the recordings of three large seismic Martian events, including S1222a, the largest event recorded by the InSight mission. These measurements, together with P-to-s receiver functions and P-wave reflection times, were utilized for performing a joint inversion of the local crustal structure at the InSight landing site. Our inversion results are compatible with previously reported intra-crustal discontinuities around 10 and 20 km depths, whereas the preferred models show a strong discontinuity at ∼37 km, which is interpreted as the crust-mantle interface. Additionally, we support the presence of a shallow low-velocity layer of 2–3 km thickness. Compared to nearby regions, lower seismic wave velocities are derived for the crust, suggesting a higher porosity or alteration of the whole local crust.

Published
2023

7. Separation of source, attenuation and site parameters of 2 moderate earthquakes in France: an elastic radiative transfer approach

Author

Heller, G., Margerin, L., Sèbe, O., Mayor, J., Calvet, M., and Traversa, P.

Abstract

An accurate magnitude estimation is necessary to properly evaluate seismic hazard. Unfortunately, magnitudes of small earthquakes are subject to large uncertainties due to high-frequency propagation effects which are generally not properly considered. To address this issue, we developed a method to separate source, attenuation and site parameters from the elastic radiative transfer modeling of the full energy envelopes of seismograms. The key feature of our approach is the treatment of attenuation -both scattering and absorption- in a simple but realistic velocity model of the Earth's lithosphere, including a velocity discontinuity at the Moho.Our separation method is based on a 2-steps inversion procedure. First, for each source-station pair, we retrieve optimal frequency-dependent attenuation parameters from the fitting of observed energy envelopes in the 0.375-24Hz band. In a second step, we correct for regional propagation effects to determine site amplification and source displacement spectra. From the latter, we estimate the moment magnitude Mw.The inversion procedure is applied to the 2019 ML 5.2 Le Teil and 2014 ML 4.5 Lourdes earthquakes, which both occurred in Southern France. The inversion results confirm a significant variability in the attenuation parameters (scattering and intrinsic absorption) at regional scale and a strongfrequencydependence. We determine moment magnitudes Mw 5.07±0.17 for the Le Teil earthquake and 4.13±0.13 for the Lourdes earthquake, in good agreement with previous estimates. In the future, we intend to automate our method and apply it routinely to smaller earthquakes for which traditional methods are not readily applicable due to the complexity of waveforms., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

Published
2023
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8. Stratification of heterogeneity in the lithosphere of Mars from envelope modeling of very high-frequency seismic events

Author

Menina, S., Margerin, L., Kawamura, T., Heller, G., Mélanie, D., Xu, Z., Calvet, M., Garcia, R., knapmeyer-endrun, B., Carrasco, S., Onodera, K., Lognonné, P., Stott, A., and Banerdt, W.

Abstract

Following its deployment at the surface of Mars, the seismometer SEIS of the InSIght – NASA Mission has detected tens of very high-frequency (VF) seismic events (> 1 Hz). In this work, we constrain the regional attenuation properties of the Martian lithosphere using both impacts and VF datato characterize the heterogeneities and volatile content as a function of depth. To carry out this task, we model the high-frequency energy envelopes of the seismic events using a multiple-scattering approach, considering a stratification ofvelocity andattenuation in the medium. In a first approximation, we consider a simple attenuation structure composed of a heterogenous crust overlying a weakly inhomogeneous mantle. Our inversion results show that a strongly diffusive and globally dry layer of about 20 km thickness in the vicinity of the InSight landing site (northern plains) suffices to retrieve the shape of near impacts, but the thickness has to be increased to at least 60 km to recover the shape of distant VF events. The observed correlation between the depth extent of the diffusive layer and the thickness of the crust indicates that the main cause of scattering is the lithological heterogeneity.Furthermore, our modelsuggests that the sources of a number of distant VF seismic events are shallow and located in the southern highlands or in close vicinity of the Martian dichotomy.&nbsp, The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

Published
2023
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9. A Cerberus Fossae Seismic Network

Author

Stähler, S., Panning, M., Antonangeli, D., Banerdt, B., Banfield, D., Banks, M., Ceylan, S., Charalambous, C., Clinton, John, Daubar, I., Fernando, B., Giardini, D., Grott, Matthias, Horleston, A., Hurst, K., Kawamura, T., Khan, A., Kim, D., Knapmeyer, Martin, Knapmeyer-Endrun, B., Lorenz, R. D., Margerin, L., Marusiak, A, Menina, S., Mittelholz, A., Murdoch, N., Nishikawa, Yasuhiro, Nunn, C., Perrin, C., Pike, W.T., Schmelzbach, C., Schmerr, N., Schimmel, M., Spiga, A., Stott, A., Taylor, Jake, and Weber, R.

Subjects
Mars Seismology Missions
Published
2023

10. Newly formed craters on Mars located using seismic and acoustic wave data from InSight

Author

Garcia, R.F., Daubar, I.J., Beucler, É., Posiolova, L.V., Collins, G.S., Lognonné, P., Rolland, L., Xu, Z., Wójcicka, N., Spiga, A., Fernando, B., Speth, G., Martire, L., Rajšić, Andrea, Miljković, Katarina, Sansom, Eleanor, Charalambous, C., Ceylan, S., Menina, S., Margerin, L., Lapeyre, R., Neidhart, Tanja, Teanby, N.A., Schmerr, N.C., Bonnin, M., Froment, M., Clinton, J.F., Karatekin, O., Stähler, S.C., Dahmen, N.L., Durán, C., Horleston, A., Kawamura, T., Plasman, M., Zenhäusern, G., Giardini, D., Panning, M., Malin, M., Banerdt, W.B., Garcia, R.F., Daubar, I.J., Beucler, É., Posiolova, L.V., Collins, G.S., Lognonné, P., Rolland, L., Xu, Z., Wójcicka, N., Spiga, A., Fernando, B., Speth, G., Martire, L., Rajšić, Andrea, Miljković, Katarina, Sansom, Eleanor, Charalambous, C., Ceylan, S., Menina, S., Margerin, L., Lapeyre, R., Neidhart, Tanja, Teanby, N.A., Schmerr, N.C., Bonnin, M., Froment, M., Clinton, J.F., Karatekin, O., Stähler, S.C., Dahmen, N.L., Durán, C., Horleston, A., Kawamura, T., Plasman, M., Zenhäusern, G., Giardini, D., Panning, M., Malin, M., and Banerdt, W.B.

Abstract

Meteoroid impacts shape planetary surfaces by forming new craters and alter atmospheric composition. During atmospheric entry and impact on the ground, meteoroids excite transient acoustic and seismic waves. However, new crater formation and the associated impact-induced mechanical waves have yet to be observed jointly beyond Earth. Here we report observations of seismic and acoustic waves from the NASA InSight lander’s seismometer that we link to four meteoroid impact events on Mars observed in spacecraft imagery. We analysed arrival times and polarization of seismic and acoustic waves to estimate impact locations, which were subsequently confirmed by orbital imaging of the associated craters. Crater dimensions and estimates of meteoroid trajectories are consistent with waveform modelling of the recorded seismograms. With identified seismic sources, the seismic waves can be used to constrain the structure of the Martian interior, corroborating previous crustal structure models, and constrain scaling relationships between the distance and amplitude of impact-generated seismic waves on Mars, supporting a link between the seismic moment of impacts and the vertical impactor momentum. Our findings demonstrate the capability of planetary seismology to identify impact-generated seismic sources and constrain both impact processes and planetary interiors.

Published
2022

11. Largest recent impact craters on Mars: Orbital imaging and surface seismic co-investigation

Author

Posiolova, L.V., Lognonné, P., Banerdt, W.B., Clinton, J., Collins, G.S., Kawamura, T., Ceylan, S., Daubar, I.J., Fernando, B., Froment, M., Giardini, D., Malin, M.C., Miljković, Katarina, Stähler, S.C., Xu, Z., Banks, M.E., Beucler, Cantor, B.A., Charalambous, C., Dahmen, N., Davis, P., Drilleau, M., Dundas, C.M., Durán, C., Euchner, F., Garcia, R.F., Golombek, M., Horleston, A., Keegan, C., Khan, A., Kim, D., Larmat, C., Lorenz, R., Margerin, L., Menina, S., Panning, M., Pardo, C., Perrin, C., Pike, W.T., Plasman, M., Rajšić, Andrea, Rolland, L., Rougier, E., Speth, G., Spiga, A., Stott, A., Susko, D., Teanby, N.A., Valeh, A., Werynski, A., Wójcicka, N., Zenhäusern, G., Posiolova, L.V., Lognonné, P., Banerdt, W.B., Clinton, J., Collins, G.S., Kawamura, T., Ceylan, S., Daubar, I.J., Fernando, B., Froment, M., Giardini, D., Malin, M.C., Miljković, Katarina, Stähler, S.C., Xu, Z., Banks, M.E., Beucler, Cantor, B.A., Charalambous, C., Dahmen, N., Davis, P., Drilleau, M., Dundas, C.M., Durán, C., Euchner, F., Garcia, R.F., Golombek, M., Horleston, A., Keegan, C., Khan, A., Kim, D., Larmat, C., Lorenz, R., Margerin, L., Menina, S., Panning, M., Pardo, C., Perrin, C., Pike, W.T., Plasman, M., Rajšić, Andrea, Rolland, L., Rougier, E., Speth, G., Spiga, A., Stott, A., Susko, D., Teanby, N.A., Valeh, A., Werynski, A., Wójcicka, N., and Zenhäusern, G.

Abstract

Two >130-meter-diameter impact craters formed on Mars during the later half of 2021. These are the two largest fresh impact craters discovered by the Mars Reconnaissance Orbiter since operations started 16 years ago. The impacts created two of the largest seismic events (magnitudes greater than 4) recorded by InSight during its 3-year mission. The combination of orbital imagery and seismic ground motion enables the investigation of subsurface and atmospheric energy partitioning of the impact process on a planet with a thin atmosphere and the first direct test of martian deep-interior seismic models with known event distances. The impact at 35°N excavated blocks of water ice, which is the lowest latitude at which ice has been directly observed on Mars.

Published
2022

13. 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

14. Autocorrelation of the Ground Vibrations Recorded by the SEIS-InSight Seismometer on Mars

Author

Compaire, N., Margerin, L., Garcia, R. F., Pinot, B., Calvet, M., Orhand-Mainsant, G., Kim, D., Lekic, V., Tauzin, B., Schimmel, M., Stutzmann, E., Knapmeyer-Endrun, B., Lognonne, P., Pike, W. T., Schmerr, N., Gizon, L., Banerdt, W. B., Compaire, N., Margerin, L., Garcia, R. F., Pinot, B., Calvet, M., Orhand-Mainsant, G., Kim, D., Lekic, V., Tauzin, B., Schimmel, M., Stutzmann, E., Knapmeyer-Endrun, B., Lognonne, P., Pike, W. T., Schmerr, N., Gizon, L., and Banerdt, W. B.

Abstract

Since early February 2019, the SEIS (Seismic Experiment for Interior Structure) seismometer deployed at the surface of Mars in the framework of the InSight mission has been continuously recording the ground motion at Elysium Planitia. In this study, we take advantage of this exceptional data set to put constraints on the crustal properties of Mars using seismic interferometry (SI). To carry out this task, we first examine the continuous records from the very broadband seismometer. Several deterministic sources of environmental noise are identified and specific preprocessing strategies are presented to mitigate their influence. Applying the principles of SI to the single-station configuration of InSight, we compute, for each Sol and each hour of the martian day, the diagonal elements of the time-domain correlation tensor of random ambient vibrations recorded by SEIS. A similar computation is performed on the diffuse waveforms generated by more than a hundred Marsquakes. A careful signal-to-noise ratio analysis and an inter-comparison between the two datasets suggest that the results from SI are most reliable in a narrow frequency band around 2.4 Hz, where an amplification of both ambient vibrations and seismic events is observed. The average autocorrelation functions (ACFs) contain well identifiable seismic arrivals, that are very consistent between the two datasets. Interpreting the vertical and horizontal ACFs as, respectively, the P- and S- seismic reflectivity below InSight, we propose a simple stratified velocity model of the crust, which is mostly compatible with previous results from receiver function analysis. Our results are discussed and compared to recent works from the literature.

Published
2021

15. Autocorrelation of the Ground Vibrations Recorded by the SEIS-InSight Seismometer on Mars

Author

Compaire, N, Margerin, L, Garcia, R F, Pinot, B, Calvet, M, Orhand-Mainsant, G, Kim, D, Lekic, Vedran, Tauzin, Benoit, Schimmel, M, Stutzmann, E, Compaire, N, Margerin, L, Garcia, R F, Pinot, B, Calvet, M, Orhand-Mainsant, G, Kim, D, Lekic, Vedran, Tauzin, Benoit, Schimmel, M, and Stutzmann, E

Abstract

Since early February 2019, the SEIS (Seismic Experiment for Interior Structure) seismometer deployed at the surface of Mars in the framework of the InSight mission has been continuously recording the ground motion at Elysium Planitia. In this study, we take advantage of this exceptional data set to put constraints on the crustal properties of Mars using seismic interferometry (SI). To carry out this task, we first examine the continuous records from the very broadband seismometer. Several deterministic sources of environmental noise are identified and specific preprocessing strategies are presented to mitigate their influence. Applying the principles of SI to the single-station configuration of InSight, we compute, for each Sol and each hour of the martian day, the diagonal elements of the time-domain correlation tensor of random ambient vibrations recorded by SEIS. A similar computation is performed on the diffuse waveforms generated by more than a hundred Marsquakes. A careful signal-to-noise ratio analysis and an inter-comparison between the two datasets suggest that the results from SI are most reliable in a narrow frequency band around 2.4 Hz, where an amplification of both ambient vibrations and seismic events is observed. The average autocorrelation functions (ACFs) contain well identifiable seismic arrivals, that are very consistent between the two datasets. Interpreting the vertical and horizontal ACFs as, respectively, the P- and S- seismic reflectivity below InSight, we propose a simple stratified velocity model of the crust, which is mostly compatible with previous results from receiver function analysis. Our results are discussed and compared to recent works from the literature.

Published
2021

16. The Polarization of Ambient Noise on Mars

Author

Agence Nationale de la Recherche (France), UK Space Agency, Ministerio de Ciencia, Innovación y Universidades (España), Schimmel, Martin [0000-0003-2601-4462], Stutzmann, E., Schimmel, Martin, Lognonné, P., Horleston, A., Ceylan, S., van Driel, M., Stähler, S., Banerdt, B., Calvet, M., Charalambous, C., Clinton, John F., Drilleau, M., Fayon, L., Garcia, R. F., Giardini, Domenico, Hurst, K., Jacob, A., Kawamura, T., Kenda, B., Margerin, L., Murdoch, N., Panning, M., Pike, T., Scholz, J. R., Spiga, A., Agence Nationale de la Recherche (France), UK Space Agency, Ministerio de Ciencia, Innovación y Universidades (España), Schimmel, Martin [0000-0003-2601-4462], Stutzmann, E., Schimmel, Martin, Lognonné, P., Horleston, A., Ceylan, S., van Driel, M., Stähler, S., Banerdt, B., Calvet, M., Charalambous, C., Clinton, John F., Drilleau, M., Fayon, L., Garcia, R. F., Giardini, Domenico, Hurst, K., Jacob, A., Kawamura, T., Kenda, B., Margerin, L., Murdoch, N., Panning, M., Pike, T., Scholz, J. R., and Spiga, A.

Abstract

Seismic noise recorded at the surface of Mars has been monitored since February 2019, using the InSight seismometers. This noise can reach -200 dB. It is 500 times lower than on Earth at night and it increases of 30 dB during the day. We analyze its polarization as a function of time and frequency in the band 0.03-1 Hz. We use the degree of polarization to extract signals with stable polarization independent of their amplitude and type of polarization. We detect polarized signals at all frequencies and all times. Glitches correspond to linear polarized signals which are more abundant during the night. For signals with elliptical polarization, the ellipse is in the horizontal plane below 0.3 Hz. In the 0.3-1Hz high frequency band (HF) and except in the evening, the ellipse is in the vertical plane and the major axis is tilted. While polarization azimuths are different in the two frequency bands, they both vary as a function of local hour and season. They are also correlated with wind direction, particularly during the daytime. We investigate possible aseismic and seismic origins of the polarized signals. Lander or tether noise can be discarded. Pressure fluctuations transported by wind may explain part of the HF polarization but not the tilt of the ellipse. This tilt can be obtained if the source is an acoustic emission coming from high altitude at critical angle. Finally, in the evening when the wind is low, the measured polarized signals may correspond to the seismic wavefield of the Mars background noise. Plain Language Summary Seismic noise at the surface of Mars was unknown until the first measurements by the seismometers from the InSight mission in January 2019. On Earth, the microseismic noise (0.05-1 Hz) is composed dominantly of surface waves generated by the numerous sources related to ocean wave activities. On Mars, because there is no ocean, seismic noise is down to 500 times lower than on Earth reaching -200 dB in acceleration at night. In order to deter

Published
2021

17. 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

18. 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

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

Author

Knapmeyer-Endrun, B., Panning, M., Bissig, Felix, Joshi, Rakshit, Khan, A., Kim, Doyeon, Lekic, V., Tauzin, B., Tharimena, S., Plasman, Matthieu, Compaire, Nicolas, Garcia, Raphaël F., Margerin, L., Schimmel, M., Stutzmann, Éléonore, Schmerr, N., Antonangeli, D., Bozdag, E., McLennan, S M, Peter, Daniel, Plesa, Ana-Catalina, Samuel, H., Wieczorek, M., Davis, Paul, Lognonne, P., Pinot, Baptiste, Scholz, J.-R., Stähler, S., Knapmeyer, Martin, Brinkmann, Nienke, van Driel, M, Giardini, D., Johnson, Catherine L., Smrekar, S., and Banerdt, B.

Subjects
receiver functions, crustal thickness, Mars, seismological constraints, InSight
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 functions for three Apollo landing sites, including the first application of this method to Apollo 15 and 16 data. Data are compatible with a two-layer crust beneath a thin, low-velocity regolith layer and a crustal thickness of 35 to 45 km, with an increased thickness at the Apollo 15 and 16 sites compared to the Apollo12 location.

Published
2020

20. 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

21. Coda-Q in the 2.5-20 s period band from seismic noise : application to the greater Alpine area

Author

Soergel, D., Pedersen, H. A., Stehly, L., Margerin, L., Paul, A., Hetenyi, G., Abreu, R., Allegretti, I., Apoloner, M. T., Aubert, C., De Berc, M. B., Bokelmann, G., Brunel, D., Capello, M., Carman, M., Cavaliere, A., Cheze, J., Chiarabba, C., Clinton, J., Cougoulat, G., Crawford, W., Cristiano, L., Czifra, T., D'Alema, E., Danesi, S., Daniel, R., Dasovic, I., Deschamps, A., Dessa, J. X., Doubre, C., Egdorf, S., Fiket, T., Fischer, K., Friederich, W., Fuchs, F., Funke, S., Giardini, D., Govoni, A., Graczer, Z., Groschl, G., Heimers, S., Heit, B., Herak, D., Herak, M., Huber, J., Jaric, D., Jedlicka, P., Jia, Y., Jund, H., Kissling, E., Klingen, S., Klotz, B., Kolinsky, P., Korn, M., Kotek, J., Kuhne, L., Kuk, K., Loos, J., Malengros, D., Margheriti, L., Maron, C., Martin, X., Massa, M., Mazzarini, F., Meier, T., Metral, L., Molinari, I., Moretti, M., Munzarova, H., Nardi, A., Pahor, J., Pequegnat, C., Pesaresi, D., Piccinini, D., Piromallo, C., Plenefisch, T., Plomerova, J., Pondrelli, S., Prevolnik, S., Racine, R., Régnier, Marc, Reiss, M., Ritter, J., Rumpker, G., Salimbeni, S., Schulte-Kortnack, D., Scherer, W., Schippkus, S., Sipka, V., Spallarossa, D., Spieker, K., Stipcevic, J., Strollo, A., Sule, B., Szanyi, G., Szucs, E., Thomas, C., Tilmann, F., Ueding, S., Vallocchia, M., Vecsey, L., Voigt, R., Wassermann, J., Weber, Z., Weidle, C., Wesztergom, V., Weyland, G., Wiemer, S., Wolyniec, D., Zieke, T., Zivvic, M., AlpArray Working Group, Soergel, D., Pedersen, H. A., Stehly, L., Margerin, L., Paul, A., Hetenyi, G., Abreu, R., Allegretti, I., Apoloner, M. T., Aubert, C., De Berc, M. B., Bokelmann, G., Brunel, D., Capello, M., Carman, M., Cavaliere, A., Cheze, J., Chiarabba, C., Clinton, J., Cougoulat, G., Crawford, W., Cristiano, L., Czifra, T., D'Alema, E., Danesi, S., Daniel, R., Dasovic, I., Deschamps, A., Dessa, J. X., Doubre, C., Egdorf, S., Fiket, T., Fischer, K., Friederich, W., Fuchs, F., Funke, S., Giardini, D., Govoni, A., Graczer, Z., Groschl, G., Heimers, S., Heit, B., Herak, D., Herak, M., Huber, J., Jaric, D., Jedlicka, P., Jia, Y., Jund, H., Kissling, E., Klingen, S., Klotz, B., Kolinsky, P., Korn, M., Kotek, J., Kuhne, L., Kuk, K., Loos, J., Malengros, D., Margheriti, L., Maron, C., Martin, X., Massa, M., Mazzarini, F., Meier, T., Metral, L., Molinari, I., Moretti, M., Munzarova, H., Nardi, A., Pahor, J., Pequegnat, C., Pesaresi, D., Piccinini, D., Piromallo, C., Plenefisch, T., Plomerova, J., Pondrelli, S., Prevolnik, S., Racine, R., Régnier, Marc, Reiss, M., Ritter, J., Rumpker, G., Salimbeni, S., Schulte-Kortnack, D., Scherer, W., Schippkus, S., Sipka, V., Spallarossa, D., Spieker, K., Stipcevic, J., Strollo, A., Sule, B., Szanyi, G., Szucs, E., Thomas, C., Tilmann, F., Ueding, S., Vallocchia, M., Vecsey, L., Voigt, R., Wassermann, J., Weber, Z., Weidle, C., Wesztergom, V., Weyland, G., Wiemer, S., Wolyniec, D., Zieke, T., Zivvic, M., and AlpArray Working Group

Abstract

Coda-Q is used to estimate the attenuation and scattering properties of the Earth. So far focus has been on earthquake data at frequencies above 1 Hz, as the high noise level in the first and second microseismic peak, and possibly lower scattering coefficient, hinder stable measurements at lower frequencies. In this work, we measure and map coda-Q in the period bands 2.5-5 s, 5-10 s and 10-20 s in the greater Alpine region using noise cross-correlations between station pairs, based on data from permanent seismic stations and from the temporary AlpArray experiment. The observed coda-Q for short interstation distances is independent of azimuth so there is no indication of influence of the directivity of the incoming noise field on our measurements. In the 2.5-5 s and 5-10 s period bands, our measurements are self-consistent, and we observe stable geographic patterns of low and high coda-Q in the period bands 2.5-5 s and 5-10 s. In the period band 10-20 s, the dispersion of our measurements increases and geographic patterns become speculative. The coda-Q maps show that major features are observed with high resolution, with a very good geographical resolution of for example low coda-Q in the Po Plain. There is a sharp contrast between the Po Plain and the Alps and Apennines where coda-Q is high, with the exception a small area in the Swiss Alps which may be contaminated by the low coda-Q of the Po Plain. The coda of the correlations is too short to make independent measurements at different times within the coda, so we cannot distinguish between intrinsic and scattering Q. Measurements on more severely selected data sets and longer time-series result in identical geographical patterns but lower numerical values. Therefore, high coda-Q values may be overestimated, but the geographic distribution between high and low coda-Q areas is respected. Our results demonstrate that noise correlations are a promising tool for extending coda-Q measurements to frequencies lower than t

Published
2020

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

Author

Lognonne, 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., Staehler, S., Stott, A., Stutzmann, E., Tharimena, S., Widmer-Schnidrig, R., Andersson, F., Ansan, V., Beghein, C., Boese, 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., Zweifel, P., Lognonne, 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., Staehler, S., Stott, A., Stutzmann, E., Tharimena, S., Widmer-Schnidrig, R., Andersson, F., Ansan, V., Beghein, C., Boese, 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.

Abstract

The crust beneath the InSight lander on Mars is altered or fractured to 8-11 km depth and may bear volatiles, according to an analysis of seismic noise and wave scattering recorded by InSight's seismometer. 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

23. The seismicity of Mars

Author

Giardini, D., Lognonne, P., Banerdt, W. B., Pike, W. T., Christensen, U., Ceylan, S., Clinton, J. F., van Driel, M., Staehler, S. C., Boese, M., Garcia, R. F., Khan, A., Panning, M., Perrin, C., Banfield, D., Beucler, E., Charalambous, C., Euchner, F., Horleston, A., Jacob, A., Kawamura, T., Kedar, S., Mainsant, G., Scholz, J. -R., Smrekar, S. E., Spiga, A., Agard, C., Antonangeli, D., Barkaoui, S., Barrett, E., Combes, P., Conejero, V., Daubar, I., Drilleau, M., Ferrier, C., Gabsi, T., Gudkova, T., Hurst, K., Karakostas, F., King, S., Knapmeyer, M., Knapmeyer-Endrun, B., Llorca-Cejudo, R., Lucas, A., Luno, L., Margerin, L., McClean, J. B., Mimoun, D., Murdoch, N., Nimmo, F., Nonon, M., Pardo, C., Rivoldini, A., Manfredi, J. A. Rodriguez, Samuel, H., Schimmel, M., Stott, A. E., Stutzmann, E., Teanby, N., Warren, T., Weber, R. C., Wieczorek, M., Yana, C., Giardini, D., Lognonne, P., Banerdt, W. B., Pike, W. T., Christensen, U., Ceylan, S., Clinton, J. F., van Driel, M., Staehler, S. C., Boese, M., Garcia, R. F., Khan, A., Panning, M., Perrin, C., Banfield, D., Beucler, E., Charalambous, C., Euchner, F., Horleston, A., Jacob, A., Kawamura, T., Kedar, S., Mainsant, G., Scholz, J. -R., Smrekar, S. E., Spiga, A., Agard, C., Antonangeli, D., Barkaoui, S., Barrett, E., Combes, P., Conejero, V., Daubar, I., Drilleau, M., Ferrier, C., Gabsi, T., Gudkova, T., Hurst, K., Karakostas, F., King, S., Knapmeyer, M., Knapmeyer-Endrun, B., Llorca-Cejudo, R., Lucas, A., Luno, L., Margerin, L., McClean, J. B., Mimoun, D., Murdoch, N., Nimmo, F., Nonon, M., Pardo, C., Rivoldini, A., Manfredi, J. A. Rodriguez, Samuel, H., Schimmel, M., Stott, A. E., Stutzmann, E., Teanby, N., Warren, T., Weber, R. C., Wieczorek, M., and Yana, C.

Abstract

The InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) mission landed in Elysium Planitia on Mars on 26 November 2018 and fully deployed its seismometer by the end of February 2019. The mission aims to detect, characterize and locate seismic activity on Mars, and to further constrain the internal structure, composition and dynamics of the planet. Here, we present seismometer data recorded until 30 September 2019, which reveal that Mars is seismically active. We identify 174 marsquakes, comprising two distinct populations: 150 small-magnitude, high-frequency events with waves propagating at crustal depths and 24 low-frequency, subcrustal events of magnitude M-w 3-4 with waves propagating at various depths in the mantle. These marsquakes have spectral characteristics similar to the seismicity observed on the Earth and Moon. We determine that two of the largest detected marsquakes were located near the Cerberus Fossae fracture system. From the recorded seismicity, we constrain attenuation in the crust and mantle, and find indications of a potential low-S-wave-velocity layer in the upper mantle. Mars is seismically active: 24 subcrustal magnitude 3-4 marsquakes and 150 smaller events have been identified up to 30 September 2019, by an analysis of seismometer data from the InSight lander.

Published
2020

24. A New Crater Near InSight: Implications for Seismic Impact Detectability on Mars

Author

Daubar, I.J., Lognonné, P., Teanby, N.A., Collins, G.S., Clinton, J., Stähler, S., Spiga, A., Karakostas, F., Ceylan, S., Malin, M., McEwen, A.S., Maguire, R., Charalambous, C., Onodera, K., Lucas, A., Rolland, L., Vaubaillon, J., Kawamura, T., Böse, M., Horleston, A., van Driel, M., Stevanović, J., Miljkovic, Katarina, Fernando, B., Huang, Q., Giardini, D., Larmat, C.S., Leng, K., Rajšić, A., Schmerr, N., Wójcicka, N., Pike, T., Wookey, J., Rodriguez, S., Garcia, R., Banks, M.E., Margerin, L., Posiolova, L., Banerdt, B., Daubar, I.J., Lognonné, P., Teanby, N.A., Collins, G.S., Clinton, J., Stähler, S., Spiga, A., Karakostas, F., Ceylan, S., Malin, M., McEwen, A.S., Maguire, R., Charalambous, C., Onodera, K., Lucas, A., Rolland, L., Vaubaillon, J., Kawamura, T., Böse, M., Horleston, A., van Driel, M., Stevanović, J., Miljkovic, Katarina, Fernando, B., Huang, Q., Giardini, D., Larmat, C.S., Leng, K., Rajšić, A., Schmerr, N., Wójcicka, N., Pike, T., Wookey, J., Rodriguez, S., Garcia, R., Banks, M.E., Margerin, L., Posiolova, L., and Banerdt, B.

Abstract

A new 1.5 m diameter impact crater was discovered on Mars only ~40 km from the InSight lander. Context camera images constrained its formation between 21 February and 6 April 2019; follow-up High Resolution Imaging Science Experiment images resolved the crater. During this time period, three seismic events were identified in InSight data. We derive expected seismic signal characteristics and use them to evaluate each of the seismic events. However, none of them can definitively be associated with this source. Atmospheric perturbations are generally expected to be generated during impacts; however, in this case, no signal could be identified as related to the known impact. Using scaling relationships based on the terrestrial and lunar analogs and numerical modeling, we predict the amplitude, peak frequency, and duration of the seismic signal that would have emanated from this impact. The predicted amplitude falls near the lowest levels of the measured seismometer noise for the predicted frequency. Hence, it is not surprising this impact event was not positively identified in the seismic data. Finding this crater was a lucky event as its formation this close to InSight has a probability of only ~0.2, and the odds of capturing it in before and after images are extremely low. We revisit impact-seismic discriminators in light of real experience with a seismometer on the Martian surface. Using measured noise of the instrument, we revise our previous prediction of seismic impact detections downward, from ~a few to tens, to just ~2 per Earth year, still with an order of magnitude uncertainty.

Published
2020

25. 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

26. The seismicity of Mars

Author

Swiss National Supercomputing Centre, Swiss National Science Foundation, Agence Nationale de la Recherche (France), State Secretariat for Education, Research and Innovation (Switzerland), UK Space Agency, California Institute of Technology, German Centre for Air and Space Travel, Schimmel, Martin [0000-0003-2601-4462], Giardini, Domenico, Lognonné, P., Banerdt, W. B., Pike, William T., Christensen, U., Ceylan, S., Clinton, John F., van Driel, M., Stähler, S. C., Böse, M., Garcia, R. F., Khan, A., Panning, M., Perrin, C., Banfield, D., Beucler, E., Charalambous, C., Euchner, F., Horleston, A., Jacob, A., Kawamura, T., Kedar, S., Mainsant, G., Scholz, J. R., Smrekar, S. E., Spiga, A., Agard, C., Antonangeli, D., Barkaoui, S., Barrett, E., Combes, P., Conejero, Vicente, Daubar, I., Drilleau, M., Ferrier, C., Gabsi, T., Gudkova, T., Hurst, K., Karakostas, F., King, S., Knapmeyer, M., Knapmeyer‐Endrun, Brigitte, Llorca-Cejudo, R., Lucas, A., Luno, L., Margerin, L., McClean, J. B., Mimoun, D., Murdoch, N., Nimmo, F., Nonon, M., Pardo, C., Rivoldini, A., Manfredi, J. A. R., Samuel, H., Schimmel, Martin, Stott, A. E., Stutzmann, E., Teanby, N., Warren, T., Weber, R. C., Wieczorek, M., Yana, C., Swiss National Supercomputing Centre, Swiss National Science Foundation, Agence Nationale de la Recherche (France), State Secretariat for Education, Research and Innovation (Switzerland), UK Space Agency, California Institute of Technology, German Centre for Air and Space Travel, Schimmel, Martin [0000-0003-2601-4462], Giardini, Domenico, Lognonné, P., Banerdt, W. B., Pike, William T., Christensen, U., Ceylan, S., Clinton, John F., van Driel, M., Stähler, S. C., Böse, M., Garcia, R. F., Khan, A., Panning, M., Perrin, C., Banfield, D., Beucler, E., Charalambous, C., Euchner, F., Horleston, A., Jacob, A., Kawamura, T., Kedar, S., Mainsant, G., Scholz, J. R., Smrekar, S. E., Spiga, A., Agard, C., Antonangeli, D., Barkaoui, S., Barrett, E., Combes, P., Conejero, Vicente, Daubar, I., Drilleau, M., Ferrier, C., Gabsi, T., Gudkova, T., Hurst, K., Karakostas, F., King, S., Knapmeyer, M., Knapmeyer‐Endrun, Brigitte, Llorca-Cejudo, R., Lucas, A., Luno, L., Margerin, L., McClean, J. B., Mimoun, D., Murdoch, N., Nimmo, F., Nonon, M., Pardo, C., Rivoldini, A., Manfredi, J. A. R., Samuel, H., Schimmel, Martin, Stott, A. E., Stutzmann, E., Teanby, N., Warren, T., Weber, R. C., Wieczorek, M., and Yana, C.

Abstract

The InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) mission landed in Elysium Planitia on Mars on 26 November 2018 and fully deployed its seismometer by the end of February 2019. The mission aims to detect, characterize and locate seismic activity on Mars, and to further constrain the internal structure, composition and dynamics of the planet. Here, we present seismometer data recorded until 30 September 2019, which reveal that Mars is seismically active. We identify 174 marsquakes, comprising two distinct populations: 150 small-magnitude, high-frequency events with waves propagating at crustal depths and 24 low-frequency, subcrustal events of magnitude Mw 3–4 with waves propagating at various depths in the mantle. These marsquakes have spectral characteristics similar to the seismicity observed on the Earth and Moon. We determine that two of the largest detected marsquakes were located near the Cerberus Fossae fracture system. From the recorded seismicity, we constrain attenuation in the crust and mantle, and find indications of a potential low-S-wave-velocity layer in the upper mantle. © 2020, The Author(s), under exclusive licence to Springer Nature Limited.

Published
2020

27. Seasonal variations of subsurface seismic velocities monitored by the SEIS-InSight seismometer on Mars.

Author

Compaire, N, Margerin, L, Monnereau, M, Garcia, R F, Lange, L, Calvet, M, Dahmen, N L, Stähler, S C, Mueller, N, Grott, M, Lognonné, P, Spohn, T, and Banerdt, W B

Subjects
*SEISMIC wave velocity, *GROUND motion, *SEISMOMETERS, *RELATIVE velocity, *MARS (Planet), *SOLAR cycle, *MOTION, *REGOLITH
Abstract

The SEIS (Seismic Experiment for Interior Structure) seismometer deployed at the surface of Mars in the framework of the NASA-InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) mission has been continuously recording the ground motion at Elysium Planitia for more than one martian year. In this work, we investigate the seasonal variation of the near-surface properties using both background vibrations and a particular class of high-frequency seismic events. We present measurements of relative velocity changes over one martian year and show that they can be modelled by a thermoelastic response of the Martian regolith. Several families of high-frequency seismic multiplets have been observed at various periods of the martian year. These events exhibit complex, repeatable waveforms with an emergent character and a coda that is likely composed of scattered waves. Taking advantage of these properties, we use coda wave interferometry (CWI) to measure relative traveltime changes as a function of the date of occurrence of the quakes. While in some families a stretching of the coda waveform is clearly observed, in other families we observe either no variation or a clear contraction of the waveform. These various behaviors correspond to different conditions of illumination at the InSight landing site, depending on the season. Measurements of velocity changes from the analysis of background vibrations above 5 Hz are consistent with the results from CWI. We identify a frequency band structure in the power spectral density (PSD) that can be tracked over hundreds of days. This band structure is the equivalent in the frequency domain of an autocorrelogram and can be efficiently used to measure relative traveltime changes as a function of frequency. We explain how the PSD analysis allows us to circumvent the contamination of the measurements by the Lander mode excitation which is inevitable in the time domain. The observed velocity changes can be adequately modelled by the thermoelastic response of the regolith to the time-dependent incident solar flux at the seasonal scale. In particular, the model captures the time delay between the surface temperature variations and the velocity changes in the subsurface. Our observations could serve as a basis for a joint inversion of the seismic and thermal properties in the first 20 m below InSight. [ABSTRACT FROM AUTHOR]

Published
2022
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29. On the use of the coda of seismic noise autocorrelations to compute H/V spectral ratios.

Author

Tchawe, F N, Froment, B, Campillo, M, and Margerin, L

Subjects
MICROSEISMS, GREEN'S functions, SEDIMENTARY basins
Abstract

The horizontal to vertical spectral ratio (HVSR) of seismic ambient noise has been proven to be a fast and efficient method for characterizing the 1-D resonance frequency of the local subsurface in a practical framework. Over the last decades, theories have been developed in order to extend the exploitation of HVSR beside the frequency of its first peak, notably the diffuse field assumption (DFA) which links the HVSR to the Green's function of the local medium assuming the diffuseness of the seismic ambient noise wavefield. However, the underlying assumption of the seismic ambient noise being a diffuse, equipartitioned field may not be satisfied under certain circumstances. In order to exploit the contribution of scattering in forging diffuse wave fields, we leverage the advantages of coda waves and present a novel procedure for computing the HVSR, using the coda part of ambient noise correlations. We applied this technique to data gathered at the plio-quaternary sedimentary basin of Argostoli, Greece. Results on this data set show the potential of the method to improve the temporal stability of the HVSR measurements compared to the classical computation, and the fit with the theoretical HVSR curve derived from the DFA theory. These results suggest that this procedure could help in extracting physical information from the HVSR and thus could lead to an extended use of these measurements to characterize the mechanical properties of the medium. [ABSTRACT FROM AUTHOR]

Published
2020
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30. Coda-Q in the 2.5–20 s period band from seismic noise: application to the greater Alpine area.

Author

Soergel, D, Pedersen, H A, Stehly, L, Margerin, L, Paul, A, and Group, AlpArray Working

Subjects
MICROSEISMS, ALPINE regions, PATTERNS (Mathematics), WAVE diffraction, DIFFRACTIVE scattering, SCATTERING (Physics)
Abstract

Coda-Q is used to estimate the attenuation and scattering properties of the Earth. So far focus has been on earthquake data at frequencies above 1 Hz, as the high noise level in the first and second microseismic peak, and possibly lower scattering coefficient, hinder stable measurements at lower frequencies. In this work, we measure and map coda-Q in the period bands 2.5–5 s, 5–10 s and 10–20 s in the greater Alpine region using noise cross-correlations between station pairs, based on data from permanent seismic stations and from the temporary AlpArray experiment. The observed coda-Q for short interstation distances is independent of azimuth so there is no indication of influence of the directivity of the incoming noise field on our measurements. In the 2.5–5 s and 5–10 s period bands, our measurements are self-consistent, and we observe stable geographic patterns of low and high coda-Q in the period bands 2.5–5 s and 5–10 s. In the period band 10–20 s, the dispersion of our measurements increases and geographic patterns become speculative. The coda-Q maps show that major features are observed with high resolution, with a very good geographical resolution of for example low coda-Q in the Po Plain. There is a sharp contrast between the Po Plain and the Alps and Apennines where coda-Q is high, with the exception a small area in the Swiss Alps which may be contaminated by the low coda-Q of the Po Plain. The coda of the correlations is too short to make independent measurements at different times within the coda, so we cannot distinguish between intrinsic and scattering Q. Measurements on more severely selected data sets and longer time-series result in identical geographical patterns but lower numerical values. Therefore, high coda-Q values may be overestimated, but the geographic distribution between high and low coda-Q areas is respected. Our results demonstrate that noise correlations are a promising tool for extending coda-Q measurements to frequencies lower than those analysed with earthquake data. [ABSTRACT FROM AUTHOR]

Published
2020
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37. Imaging multiple local changes in heterogeneous media with diffuse waves.

Author

Planès T, Larose E, Rossetto V, and Margerin L

Abstract

This study focuses on imaging local changes in heterogeneous media. The method employed is demonstrated and validated using numerical experiments of acoustic wave propagation in a multiple scattering medium. Changes are simulated by adding new scatterers of different sizes at various positions in the medium, and the induced decorrelation of the diffuse (coda) waveforms is measured for different pairs of sensors. The spatial and temporal dependences of the decorrelation are modeled through a diffuse sensitivity kernel, based on the intensity transport in the medium. The inverse problem is then solved with a linear least square algorithm, which leads to a map of scattering cross section density of the changes.

Published
2015
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38. Velocity and attenuation of scalar and elastic waves in random media: a spectral function approach.

Author

Calvet M and Margerin L

Abstract

This paper investigates the scattering of scalar and elastic waves in two-phase materials and single-mineral-cubic, hexagonal, orthorhombic-polycrystalline aggregates with randomly oriented grains. Based on the Dyson equation for the mean field, explicit expressions for the imaginary part of Green's function in the frequency-wavenumber domain (ω, p), also known as the spectral function, are derived. This approach allows the identification of propagating modes with their relative contribution, and the computation of both attenuation and phase velocity for each mode. The results should be valid from the Rayleigh (low-frequency) to the geometrical optics (high-frequency) regime. Comparisons with other approaches are presented for both scalar and elastic waves., (© 2012 Acoustical Society of America)

Published
2012
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39. Generalized optical theorems for the reconstruction of Green's function of an inhomogeneous elastic medium.

Author

Margerin L and Sato H

Abstract

This paper investigates the reconstruction of elastic Green's function from the cross-correlation of waves excited by random noise in the context of scattering theory. Using a general operator equation-the resolvent formula-Green's function reconstruction is established when the noise sources satisfy an equipartition condition. In an inhomogeneous medium, the operator formalism leads to generalized forms of optical theorem involving the off-shell T-matrix of elastic waves, which describes scattering in the near-field. The role of temporal absorption in the formulation of the theorem is discussed. Previously established symmetry and reciprocity relations involving the on-shell T-matrix are recovered in the usual far-field and infinitesimal absorption limits. The theory is applied to a point scattering model for elastic waves. The T-matrix of the point scatterer incorporating all recurrent scattering loops is obtained by a regularization procedure. The physical significance of the point scatterer is discussed. In particular this model satisfies the off-shell version of the generalized optical theorem. The link between equipartition and Green's function reconstruction in a scattering medium is discussed., (© 2011 Acoustical Society of America)

Published
2011
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40. Lopsided growth of Earth's inner core.

Author

Monnereau M, Calvet M, Margerin L, and Souriau A

Abstract

Hemispherical asymmetry is a prominent feature of Earth's inner core, but how this asymmetry relates to core growth is unknown. Based on multiple-scattering modeling of seismic velocity and attenuation measurements sampling the whole uppermost inner core, we propose that the growth of the solid core implies an eastward drift of the material, driven by crystallization in the Western Hemisphere and melting in the Eastern Hemisphere. This self-sustained translational motion generates an asymmetric distribution of sizes of iron crystals, which grow during their translation. The invoked dynamical process is still active today, which supports the idea of a young inner core.

Published
2010
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41. Generalized eigenfunctions of layered elastic media and application to diffuse fields.

Author

Margerin L

Abstract

The spectral decomposition of the elastic wave operator in a layered isotropic half-space is derived by means of standard functional analysis methods. Particular attention is paid to the coupled P-SV waves. The problem is formulated directly in terms of displacements which leads to a 2 x 2 Sturm-Liouville system. The resolvent kernel (Green's function) is expressed in terms of simple plane-wave solutions. Application of Stone's formula leads naturally to eigenfunction expansions in terms of generalized eigenvectors with oscillatory behavior at infinity. The generalized eigenfunction expansion is employed to define a diffuse field as a white noise process in modal space. By means of a Wigner transform, we calculate vertical to horizontal kinetic energy ratios in layered media, as a function of depth and frequency. Several illustrative examples are considered including energy ratios near a free surface, in the presence of a soft layer. Numerical comparisons between the generalized eigenfunction summation and a classical locked-mode approximation demonstrate the validity of the approach. The impact of the local velocity structure on the energy partitioning of a diffuse field is illustrated.

Published
2009
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