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Samuel H, Drilleau M, Rivoldini A, Xu Z, Huang Q, Garcia RF, Lekić V, Irving JCE, Badro J, Lognonné PH, Connolly JAD, Kawamura T, Gudkova T, Banerdt WB. Author Correction: Geophysical evidence for an enriched molten silicate layer above Mars's core. Nature 2024; 625:E13. [PMID: 38168625 PMCID: PMC10794131 DOI: 10.1038/s41586-023-06930-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Affiliation(s)
- Henri Samuel
- Université Paris Cité, Institut de physique du globe de Paris, CNRS, Paris, France.
| | - Mélanie Drilleau
- Institut Supérieur de l'Aéronautique et de l'Espace ISAE-SUPAERO, Toulouse, France
| | | | - Zongbo Xu
- Université Paris Cité, Institut de physique du globe de Paris, CNRS, Paris, France
| | - Quancheng Huang
- Department of Geophysics, Colorado School of Mines, Golden, CO, USA
- University of Maryland, College Park, MD, USA
| | - Raphaël F Garcia
- Institut Supérieur de l'Aéronautique et de l'Espace ISAE-SUPAERO, Toulouse, France
| | | | | | - James Badro
- Université Paris Cité, Institut de physique du globe de Paris, CNRS, Paris, France
| | - Philippe H Lognonné
- Université Paris Cité, Institut de physique du globe de Paris, CNRS, Paris, France
| | | | - Taichi Kawamura
- Université Paris Cité, Institut de physique du globe de Paris, CNRS, Paris, France
| | - Tamara Gudkova
- Schmidt Institute of Physics of the Earth, Russian Academy of Sciences, Moscow, Russia
| | - William B Banerdt
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
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Samuel H, Drilleau M, Rivoldini A, Xu Z, Huang Q, Garcia RF, Lekić V, Irving JCE, Badro J, Lognonné PH, Connolly JAD, Kawamura T, Gudkova T, Banerdt WB. Geophysical evidence for an enriched molten silicate layer above Mars's core. Nature 2023; 622:712-717. [PMID: 37880437 PMCID: PMC10600000 DOI: 10.1038/s41586-023-06601-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 08/31/2023] [Indexed: 10/27/2023]
Abstract
The detection of deep reflected S waves on Mars inferred a core size of 1,830 ± 40 km (ref. 1), requiring light-element contents that are incompatible with experimental petrological constraints. This estimate assumes a compositionally homogeneous Martian mantle, at odds with recent measurements of anomalously slow propagating P waves diffracted along the core-mantle boundary2. An alternative hypothesis is that Mars's mantle is heterogeneous as a consequence of an early magma ocean that solidified to form a basal layer enriched in iron and heat-producing elements. Such enrichment results in the formation of a molten silicate layer above the core, overlain by a partially molten layer3. Here we show that this structure is compatible with all geophysical data, notably (1) deep reflected and diffracted mantle seismic phases, (2) weak shear attenuation at seismic frequency and (3) Mars's dissipative nature at Phobos tides. The core size in this scenario is 1,650 ± 20 km, implying a density of 6.5 g cm-3, 5-8% larger than previous seismic estimates, and can be explained by fewer, and less abundant, alloying light elements than previously required, in amounts compatible with experimental and cosmochemical constraints. Finally, the layered mantle structure requires external sources to generate the magnetic signatures recorded in Mars's crust.
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Affiliation(s)
- Henri Samuel
- Université Paris Cité, Institut de physique du globe de Paris, CNRS, Paris, France.
| | - Mélanie Drilleau
- Institut Supérieur de l'Aéronautique et de l'Espace ISAE-SUPAERO, Toulouse, France
| | | | - Zongbo Xu
- Université Paris Cité, Institut de physique du globe de Paris, CNRS, Paris, France
| | - Quancheng Huang
- Department of Geophysics, Colorado School of Mines, Golden, CO, USA
- University of Maryland, College Park, MD, USA
| | - Raphaël F Garcia
- Institut Supérieur de l'Aéronautique et de l'Espace ISAE-SUPAERO, Toulouse, France
| | | | | | - James Badro
- Université Paris Cité, Institut de physique du globe de Paris, CNRS, Paris, France
| | - Philippe H Lognonné
- Université Paris Cité, Institut de physique du globe de Paris, CNRS, Paris, France
| | | | - Taichi Kawamura
- Université Paris Cité, Institut de physique du globe de Paris, CNRS, Paris, France
| | - Tamara Gudkova
- Schmidt Institute of Physics of the Earth, Russian Academy of Sciences, Moscow, Russia
| | - William B Banerdt
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
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3
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Irving JCE, Lekić V, Durán C, Drilleau M, Kim D, Rivoldini A, Khan A, Samuel H, Antonangeli D, Banerdt WB, Beghein C, Bozdağ E, Ceylan S, Charalambous C, Clinton J, Davis P, Garcia R, Horleston AC, Huang Q, Hurst KJ, Kawamura T, King SD, Knapmeyer M, Li J, Lognonné P, Maguire R, Panning MP, Plesa AC, Schimmel M, Schmerr NC, Stähler SC, Stutzmann E, Xu Z. First observations of core-transiting seismic phases on Mars. Proc Natl Acad Sci U S A 2023; 120:e2217090120. [PMID: 37094138 PMCID: PMC10161042 DOI: 10.1073/pnas.2217090120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2023] Open
Abstract
We present the first observations of seismic waves propagating through the core of Mars. These observations, made using seismic data collected by the InSight geophysical mission, have allowed us to construct the first seismically constrained models for the elastic properties of Mars' core. We observe core-transiting seismic phase SKS from two farside seismic events detected on Mars and measure the travel times of SKS relative to mantle traversing body waves. SKS travels through the core as a compressional wave, providing information about bulk modulus and density. We perform probabilistic inversions using the core-sensitive relative travel times together with gross geophysical data and travel times from other, more proximal, seismic events to seek the equation of state parameters that best describe the liquid iron-alloy core. Our inversions provide constraints on the velocities in Mars' core and are used to develop the first seismically based estimates of its composition. We show that models informed by our SKS data favor a somewhat smaller (median core radius = 1,780 to 1,810 km) and denser (core density = 6.2 to 6.3 g/cm3) core compared to previous estimates, with a P-wave velocity of 4.9 to 5.0 km/s at the core-mantle boundary, with the composition and structure of the mantle as a dominant source of uncertainty. We infer from our models that Mars' core contains a median of 20 to 22 wt% light alloying elements when we consider sulfur, oxygen, carbon, and hydrogen. These data can be used to inform models of planetary accretion, composition, and evolution.
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Affiliation(s)
- Jessica C E Irving
- School of Earth Sciences, University of Bristol, Bristol BS8 1RJ, United Kingdom
| | - Vedran Lekić
- Department of Geology, University of Maryland, College Park 20742
| | - Cecilia Durán
- Institute of Geophysics, ETH Zurich, Zurich 8092, Switzerland
| | - Mélanie Drilleau
- Institut Supérieur de l'Aéronautique et de l'Espace ISAE-SUPAERO, Toulouse 31055, France
| | - Doyeon Kim
- Institute of Geophysics, ETH Zurich, Zurich 8092, Switzerland
| | | | - Amir Khan
- Institute of Geophysics, ETH Zurich, Zurich 8092, Switzerland
- Institute of Geochemistry and Petrology, ETH Zurich, Zurich 8092, Switzerland
| | - Henri Samuel
- Université Paris Cité, Institut de physique du globe de Paris, CNRS, Paris 75005, France
| | - Daniele Antonangeli
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Paris 75005, France
| | | | - Caroline Beghein
- Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles, CA 90095
| | - Ebru Bozdağ
- Department of Applied Mathematics and Statistics & Department of Geophysics, Colorado School of Mines, Golden, CO 80401
- Department of Geophysics, Colorado School of Mines, Golden, CO 80401
| | - Savas Ceylan
- Institute of Geophysics, ETH Zurich, Zurich 8092, Switzerland
| | - Constantinos Charalambous
- Department of Electrical and Electronic Engineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - John Clinton
- Swiss Seismological Service, ETH Zurich, Zurich 8092, Switzerland
| | - Paul Davis
- Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles, CA 90095
| | - Raphaël Garcia
- Institut Supérieur de l'Aéronautique et de l'Espace ISAE-SUPAERO, Toulouse 31055, France
| | | | - Quancheng Huang
- Department of Geophysics, Colorado School of Mines, Golden, CO 80401
| | - Kenneth J Hurst
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109
| | - Taichi Kawamura
- Université Paris Cité, Institut de physique du globe de Paris, CNRS, Paris 75005, France
| | - Scott D King
- Department of Geosciences, Virginia Tech, Blacksburg, VA 24061
| | | | - Jiaqi Li
- Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles, CA 90095
| | - Philippe Lognonné
- Université Paris Cité, Institut de physique du globe de Paris, CNRS, Paris 75005, France
| | - Ross Maguire
- Department of Geology, University of Illinois Urbana-Champaign, Urbana, IL 61801
| | - Mark P Panning
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109
| | | | | | | | - Simon C Stähler
- Institute of Geophysics, ETH Zurich, Zurich 8092, Switzerland
- Physik-Institut, Universität Zürich, Zurich 8057, Switzerland
| | - Eleonore Stutzmann
- Université Paris Cité, Institut de physique du globe de Paris, CNRS, Paris 75005, France
| | - Zongbo Xu
- Université Paris Cité, Institut de physique du globe de Paris, CNRS, Paris 75005, France
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Kim D, Banerdt WB, Ceylan S, Giardini D, Lekić V, Lognonné P, Beghein C, Beucler É, Carrasco S, Charalambous C, Clinton J, Drilleau M, Durán C, Golombek M, Joshi R, Khan A, Knapmeyer-Endrun B, Li J, Maguire R, Pike WT, Samuel H, Schimmel M, Schmerr NC, Stähler SC, Stutzmann E, Wieczorek M, Xu Z, Batov A, Bozdag E, Dahmen N, Davis P, Gudkova T, Horleston A, Huang Q, Kawamura T, King SD, McLennan SM, Nimmo F, Plasman M, Plesa AC, Stepanova IE, Weidner E, Zenhäusern G, Daubar IJ, Fernando B, Garcia RF, Posiolova LV, Panning MP. Surface waves and crustal structure on Mars. Science 2022; 378:417-421. [DOI: 10.1126/science.abq7157] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
We detected surface waves from two meteorite impacts on Mars. By measuring group velocity dispersion along the impact-lander path, we obtained a direct constraint on crustal structure away from the InSight lander. The crust north of the equatorial dichotomy had a shear wave velocity of approximately 3.2 kilometers per second in the 5- to 30-kilometer depth range, with little depth variation. This implies a higher crustal density than inferred beneath the lander, suggesting either compositional differences or reduced porosity in the volcanic areas traversed by the surface waves. The lower velocities and the crustal layering observed beneath the landing site down to a 10-kilometer depth are not a global feature. Structural variations revealed by surface waves hold implications for models of the formation and thickness of the martian crust.
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Affiliation(s)
- D. Kim
- Institute of Geophysics, ETH Zürich, Zürich, Switzerland
- Department of Geology, University of Maryland, College Park, MD, USA
| | - W. B. Banerdt
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - S. Ceylan
- Institute of Geophysics, ETH Zürich, Zürich, Switzerland
| | - D. Giardini
- Institute of Geophysics, ETH Zürich, Zürich, Switzerland
| | - V. Lekić
- Department of Geology, University of Maryland, College Park, MD, USA
| | - P. Lognonné
- Université Paris Cité, Institut de physique du globe de Paris, CNRS, Paris, France
| | - C. Beghein
- Department of Earth, Planetary and Space Sciences, University of California, Los Angeles, CA, USA
| | - É. Beucler
- Nantes Université, Université Angers, Le Mans Université, CNRS, UMR 6112, Laboratoire de Planétologie et Géosciences, Nantes, France
| | - S. Carrasco
- Bensberg Observatory, University of Cologne, Bergisch Gladbach, Germany
| | - C. Charalambous
- Department of Electrical and Electronic Engineering, Imperial College London, London, UK
| | - J. Clinton
- Swiss Seismological Service, ETH Zürich, Zürich, Switzerland
| | - M. Drilleau
- Institut Supérieur de l’Aéronautique et de l’Espace ISAE-SUPAERO, Toulouse, France
| | - C. Durán
- Institute of Geophysics, ETH Zürich, Zürich, Switzerland
| | - M. Golombek
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - R. Joshi
- Max Planck Institute for Solar System Research, Göttingen, Germany
| | - A. Khan
- Institute of Geophysics, ETH Zürich, Zürich, Switzerland
- Physik-Institut, University of Zürich, Zürich, Switzerland
| | | | - J. Li
- Department of Earth, Planetary and Space Sciences, University of California, Los Angeles, CA, USA
| | - R. Maguire
- Department of Geology, University of Illinois Urbana-Champaign, Champaign, IL, USA
| | - W. T. Pike
- Bensberg Observatory, University of Cologne, Bergisch Gladbach, Germany
| | - H. Samuel
- Université Paris Cité, Institut de physique du globe de Paris, CNRS, Paris, France
| | - M. Schimmel
- Geosciences Barcelona, CSIC, Barcelona, Spain
| | - N. C. Schmerr
- Department of Geology, University of Maryland, College Park, MD, USA
| | - S. C. Stähler
- Institute of Geophysics, ETH Zürich, Zürich, Switzerland
| | - E. Stutzmann
- Université Paris Cité, Institut de physique du globe de Paris, CNRS, Paris, France
| | - M. Wieczorek
- Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Laboratoire Lagrange, Nice, France
| | - Z. Xu
- Université Paris Cité, Institut de physique du globe de Paris, CNRS, Paris, France
| | - A. Batov
- Schmidt Institute of Physics of the Earth, Russian Academy of Sciences, Moscow, Russia
| | - E. Bozdag
- Department of Geophysics, Colorado School of Mines, Golden, CO, USA
| | - N. Dahmen
- Institute of Geophysics, ETH Zürich, Zürich, Switzerland
| | - P. Davis
- Department of Earth, Planetary and Space Sciences, University of California, Los Angeles, CA, USA
| | - T. Gudkova
- Schmidt Institute of Physics of the Earth, Russian Academy of Sciences, Moscow, Russia
| | - A. Horleston
- School of Earth Sciences, University of Bristol, Bristol, UK
| | - Q. Huang
- Department of Geophysics, Colorado School of Mines, Golden, CO, USA
| | - T. Kawamura
- Université Paris Cité, Institut de physique du globe de Paris, CNRS, Paris, France
| | - S. D. King
- Department of Geosciences, Virginia Tech, Blacksburg, VA, USA
| | - S. M. McLennan
- Department of Geosciences, Stony Brook University, Stony Brook, NY, USA
| | - F. Nimmo
- Department of Earth and Planetary Sciences, University of California Santa Cruz, Santa Cruz, CA, USA
| | - M. Plasman
- Université Paris Cité, Institut de physique du globe de Paris, CNRS, Paris, France
| | - A. C. Plesa
- Institute of Planetary Research, German Aerospace Center (DLR), Berlin, Germany
| | - I. E. Stepanova
- Schmidt Institute of Physics of the Earth, Russian Academy of Sciences, Moscow, Russia
| | - E. Weidner
- Department of Earth, Planetary and Space Sciences, University of California, Los Angeles, CA, USA
| | - G. Zenhäusern
- Institute of Geophysics, ETH Zürich, Zürich, Switzerland
| | - I. J. Daubar
- Department of Earth, Environmental, and Planetary Sciences, Brown University, Providence, RI, USA
| | - B. Fernando
- Department of Earth Sciences, University of Oxford, Oxford, UK
| | - R. F. Garcia
- Institut Supérieur de l’Aéronautique et de l’Espace ISAE-SUPAERO, Toulouse, France
| | | | - M. P. Panning
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
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5
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Kim D, Lekić V, Irving JCE, Schmerr N, Knapmeyer‐Endrun B, Joshi R, Panning MP, Tauzin B, Karakostas F, Maguire R, Huang Q, Ceylan S, Khan A, Giardini D, Wieczorek MA, Lognonné P, Banerdt WB. Improving Constraints on Planetary Interiors With PPs Receiver Functions. J Geophys Res Planets 2021; 126:e2021JE006983. [PMID: 34824966 PMCID: PMC8597591 DOI: 10.1029/2021je006983] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 10/06/2021] [Accepted: 10/12/2021] [Indexed: 06/13/2023]
Abstract
Seismological constraints obtained from receiver function (RF) analysis provide important information about the crust and mantle structure. Here, we explore the utility of the free-surface multiple of the P-wave (PP) and the corresponding conversions in RF analysis. Using earthquake records, we demonstrate the efficacy of PPs-RFs before illustrating how they become especially useful when limited data is available in typical planetary missions. Using a transdimensional hierarchical Bayesian deconvolution approach, we compute robust P-to-S (Ps)- and PPs-RFs with InSight recordings of five marsquakes. Our Ps-RF results verify the direct Ps converted phases reported by previous RF analyses with increased coherence and reveal other phases including the primary multiple reverberating within the uppermost layer of the Martian crust. Unlike the Ps-RFs, our PPs-RFs lack an arrival at 7.2 s lag time. Whereas Ps-RFs on Mars could be equally well fit by a two- or three-layer crust, synthetic modeling shows that the disappearance of the 7.2 s phase requires a three-layer crust, and is highly sensitive to velocity and thickness of intra-crustal layers. We show that a three-layer crust is also preferred by S-to-P (Sp)-RFs. While the deepest interface of the three-layer crust represents the crust-mantle interface beneath the InSight landing site, the other two interfaces at shallower depths could represent a sharp transition between either fractured and unfractured materials or thick basaltic flows and pre-existing crustal materials. PPs-RFs can provide complementary constraints and maximize the extraction of information about crustal structure in data-constrained circumstances such as planetary missions.
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Affiliation(s)
- D. Kim
- Department of GeologyUniversity of MarylandCollege ParkCollege ParkMDUSA
- Institute of GeophysicsETH ZürichZürichSwitzerland
| | - V. Lekić
- Department of GeologyUniversity of MarylandCollege ParkCollege ParkMDUSA
| | | | - N. Schmerr
- Department of GeologyUniversity of MarylandCollege ParkCollege ParkMDUSA
| | | | - R. Joshi
- Max Planck Institute for Solar System ResearchGöttingenGermany
| | - M. P. Panning
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
| | - B. Tauzin
- Université de LyonUCBLENSLCNRSLGL‐TPEVilleurbanneFrance
- Research School of Earth SciencesAustralian National UniversityActonACTAustralia
| | - F. Karakostas
- Department of GeologyUniversity of MarylandCollege ParkCollege ParkMDUSA
- Istituto Nazionale di Geofisica e Vulcanologia, Sezione di BolognaBolognaItaly
| | - R. Maguire
- Department of GeologyUniversity of MarylandCollege ParkCollege ParkMDUSA
- Department of Computational Mathematics, Science, and EngineeringMichigan State UniversityEast LansingMIUSA
| | - Q. Huang
- Department of GeologyUniversity of MarylandCollege ParkCollege ParkMDUSA
- Department of PhysicsNew Mexico State UniversityLas CrucesNMUSA
| | - S. Ceylan
- Institute of GeophysicsETH ZürichZürichSwitzerland
| | - A. Khan
- Institute of GeophysicsETH ZürichZürichSwitzerland
| | - D. Giardini
- Institute of GeophysicsETH ZürichZürichSwitzerland
| | - M. A. Wieczorek
- Université Côte d'AzurObservatoire de la Côte d'AzurCNRSLaboratoire LagrangeNiceFrance
| | - P. Lognonné
- Université de ParisInstitut de Physique du Globe de ParisCNRSParisFrance
| | - W. B. Banerdt
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
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6
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Kim D, Davis P, Lekić V, Maguire R, Compaire N, Schimmel M, Stutzmann E, Irving J, Lognonné P, Scholz JR, Clinton J, Zenhäusern G, Dahmen N, Deng S, Levander A, Panning MP, Garcia RF, Giardini D, Hurst K, Knapmeyer-Endrun B, Nimmo F, Pike WT, Pou L, Schmerr N, Stähler SC, Tauzin B, Widmer-Schnidrig R, Banerdt WB. Potential Pitfalls in the Analysis and Structural Interpretation of Seismic Data from the Mars InSight Mission. Bull Seismol Soc Am 2021; 111:2982-3002. [PMID: 35001979 PMCID: PMC8739436 DOI: 10.1785/0120210123] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The Seismic Experiment for Interior Structure (SEIS) of the InSight mission to Mars, has been providing direct information on Martian interior structure and dynamics of that planet since it landed. Compared to seismic recordings on Earth, ground motion measurements acquired by SEIS on Mars are made under dramatically different ambient noise conditions, but include idiosyncratic signals that arise from coupling between different InSight sensors and spacecraft components. This work is to synthesize what is known about these signal types, illustrate how they can manifest in waveforms and noise correlations, and present pitfalls in structural interpretations based on standard seismic analysis methods. We show that glitches, a type of prominent transient signal, can produce artifacts in ambient noise correlations. Sustained signals that vary in frequency, such as lander modes which are affected by variations in temperature and wind conditions over the course of the Martian Sol, can also contaminate ambient noise results. Therefore, both types of signals have the potential to bias interpretation in terms of subsurface layering. We illustrate that signal processing in the presence of identified nonseismic signals must be informed by an understanding of the underlying physical processes in order for high fidelity waveforms of ground motion to be extracted. While the origins of most idiosyncratic signals are well understood, the 2.4 Hz resonance remains debated and the literature does not contain an explanation of its fine spectral structure. Even though the selection of idiosyncratic signal types discussed in this paper may not be exhaustive, we provide guidance on best practices for enhancing the robustness of structural interpretations.
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Affiliation(s)
- D. Kim
- Department of Geology, University of Maryland, College Park, MD, USA
| | - P. Davis
- Department of Earth, Planetary and Space Sciences, University of California, Los Angeles, CA, USA
| | - V. Lekić
- Department of Geology, University of Maryland, College Park, MD, USA
| | - R. Maguire
- Department of Geology, University of Maryland, College Park, MD, USA
- Department of Computational Mathematics, Science, and Engineering, Michigan State University, East Lansing, MI, USA
| | - N. Compaire
- Institut Supérieur de l’Aéronautique et de l’Espace SUPAERO, Toulouse, France
| | - M. Schimmel
- Geosciences Barcelona – CSIC, Barcelona, Spain
| | - E. Stutzmann
- Université de Paris, Institut de Physique du Globe de Paris, CNRS, Paris, France
| | - J.C.E. Irving
- School of Earth Sciences, University of Bristol, Bristol, UK
| | - P. Lognonné
- Université de Paris, Institut de Physique du Globe de Paris, CNRS, Paris, France
| | - J.-R. Scholz
- Max Planck Institute for Solar System Research, Göttingen, Germany
| | - J. Clinton
- Swiss Seismological Service (SED), ETH Zürich, Zürich, Switzerland
| | - G. Zenhäusern
- Institute of Geophysics, ETH Zürich, Zürich, Switzerland
| | - N. Dahmen
- Institute of Geophysics, ETH Zürich, Zürich, Switzerland
| | - S. Deng
- Department of Earth, Environmental and Planetary Sciences, Rice University, Houston, TX, USA
| | - A. Levander
- Department of Earth, Environmental and Planetary Sciences, Rice University, Houston, TX, USA
| | - M. P. Panning
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - R. F. Garcia
- Institut Supérieur de l’Aéronautique et de l’Espace SUPAERO, Toulouse, France
| | - D. Giardini
- Institute of Geophysics, ETH Zürich, Zürich, Switzerland
| | - K. Hurst
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | | | - F. Nimmo
- Department of Earth and Planetary Sciences, University of California Santa Cruz, Santa Cruz, CA, USA
| | - W. T. Pike
- Department of Electrical and Electronic Engineering, Imperial College London, London, UK
| | - L. Pou
- Department of Earth and Planetary Sciences, University of California Santa Cruz, Santa Cruz, CA, USA
| | - N. Schmerr
- Department of Geology, University of Maryland, College Park, MD, USA
| | - S. C. Stähler
- Institute of Geophysics, ETH Zürich, Zürich, Switzerland
| | - B. Tauzin
- Université de Lyon, Laboratoire de Géologie de Lyon: Terre, Planètes, Environnement, Villeurbanne, France
| | - R. Widmer-Schnidrig
- Black Forest Observatory, Institute of Geodesy, University of Stuttgart, Stuttgart, Germany
| | - W. B. Banerdt
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
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7
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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, Banerdt WB. Thickness and structure of the martian crust from InSight seismic data. Science 2021; 373:438-443. [PMID: 34437117 DOI: 10.1126/science.abf8966] [Citation(s) in RCA: 68] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 05/21/2021] [Indexed: 11/02/2022]
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.
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Affiliation(s)
- Brigitte Knapmeyer-Endrun
- Bensberg Observatory, University of Cologne, Vinzenz-Pallotti-Str. 26, 51429 Bergisch Gladbach, Germany.
| | - Mark P Panning
- Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., M/S 183-301, Pasadena, CA 91109, USA
| | - Felix Bissig
- Institute of Geophysics, ETH Zurich, Sonneggstr. 5, 8092 Zürich, Switzerland
| | - Rakshit Joshi
- Max Planck Institute for Solar System Research, Justus-von-Liebig-Weg 3, 37077 Göttingen, Germany
| | - Amir Khan
- Institute of Geophysics, ETH Zurich, Sonneggstr. 5, 8092 Zürich, Switzerland.,Physik-Institut, University of Zurich, Zurich, Switzerland
| | - Doyeon Kim
- Department of Geology, University of Maryland, College Park, 8000 Regents Dr., College Park, MD, 20782-4211, USA
| | - Vedran Lekić
- Department of Geology, University of Maryland, College Park, 8000 Regents Dr., College Park, MD, 20782-4211, USA
| | - Benoit Tauzin
- Université de Lyon, Université Claude Bernard Lyon 1, Ecole Normale Supérieure de Lyon, Université Jean Monet, CNRS, Laboratoire de Géologie de Lyon, Terre, Planètes, Environnement, F-69622 Villeurbanne, France.,Research School of Earth Sciences, The Australian National University, Canberra, ACT 0200, Australia
| | - Saikiran Tharimena
- Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., M/S 183-301, Pasadena, CA 91109, USA
| | - Matthieu Plasman
- Université de Paris, Institut de Physique du Globe de Paris, CNRS, 1 rue Jussieu, F-75005 Paris, France
| | - Nicolas Compaire
- Institut Supérieur de l'Aéronautique et de l'Espace SUPAERO, 10 Avenue Edouard Belin, 31400 Toulouse, France
| | - Raphael F Garcia
- Institut Supérieur de l'Aéronautique et de l'Espace SUPAERO, 10 Avenue Edouard Belin, 31400 Toulouse, France
| | - Ludovic Margerin
- Institut de Recherche en Astrophysique et Planétologie, Université Toulouse III Paul Sabatier, CNRS, CNES, 14 Av. E. Belin, 31400 Toulouse, France
| | | | - Éléonore Stutzmann
- Université de Paris, Institut de Physique du Globe de Paris, CNRS, 1 rue Jussieu, F-75005 Paris, France
| | - Nicholas Schmerr
- Department of Geology, University of Maryland, College Park, 8000 Regents Dr., College Park, MD, 20782-4211, USA
| | - Ebru Bozdağ
- Department of Geophysics, Colorado School of Mines, 1500 Illinois St., Golden, CO 80401, USA
| | - Ana-Catalina Plesa
- Institute of Planetary Research, German Aerospace Center (DLR), 12489 Berlin, Germany
| | - Mark A Wieczorek
- Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, Laboratoire Lagrange, 06304 Nice, France
| | - Adrien Broquet
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721, USA.,Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, Laboratoire Lagrange, 06304 Nice, France
| | - Daniele Antonangeli
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, IMPMC, 75005 Paris, France
| | - Scott M McLennan
- Department of Geosciences, Stony Brook University, Stony Brook, NY 11794-2100, USA
| | - Henri Samuel
- Université de Paris, Institut de Physique du Globe de Paris, CNRS, 1 rue Jussieu, F-75005 Paris, France
| | - Chloé Michaut
- Université de Lyon, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, Université Jean Monet, CNRS, Laboratoire de Géologie de Lyon, Terre, Planètes, Environnement, F-69007 Lyon, France.,Institut Universitaire de France, Paris, France
| | - Lu Pan
- Center for Star and Planet Formation, GLOBE Institute, University of Copenhagen, Copenhagen, Denmark
| | - Suzanne E Smrekar
- Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., M/S 183-301, Pasadena, CA 91109, USA
| | - Catherine L Johnson
- Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, BC V6T 1Z4, Canada.,Planetary Science Institute, Tucson, 1700 East Fort Lowell, Suite 106, Tucson, AZ 85719-2395, USA
| | - Nienke Brinkman
- Institute of Geophysics, ETH Zurich, Sonneggstr. 5, 8092 Zürich, Switzerland
| | - Anna Mittelholz
- Institute of Geophysics, ETH Zurich, Sonneggstr. 5, 8092 Zürich, Switzerland
| | | | - Paul M Davis
- Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles, CA 90095, USA
| | - Philippe Lognonné
- Université de Paris, Institut de Physique du Globe de Paris, CNRS, 1 rue Jussieu, F-75005 Paris, France.,Institut Universitaire de France, Paris, France
| | - Baptiste Pinot
- Institut Supérieur de l'Aéronautique et de l'Espace SUPAERO, 10 Avenue Edouard Belin, 31400 Toulouse, France
| | - John-Robert Scholz
- Max Planck Institute for Solar System Research, Justus-von-Liebig-Weg 3, 37077 Göttingen, Germany
| | - Simon Stähler
- Institute of Geophysics, ETH Zurich, Sonneggstr. 5, 8092 Zürich, Switzerland
| | - Martin Knapmeyer
- Institute of Planetary Research, German Aerospace Center (DLR), 12489 Berlin, Germany
| | - Martin van Driel
- Institute of Geophysics, ETH Zurich, Sonneggstr. 5, 8092 Zürich, Switzerland
| | - Domenico Giardini
- Institute of Geophysics, ETH Zurich, Sonneggstr. 5, 8092 Zürich, Switzerland
| | - W Bruce Banerdt
- Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., M/S 183-301, Pasadena, CA 91109, USA
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8
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Magrini F, Boschi L, Gualtieri L, Lekić V, Cammarano F. Rayleigh-wave attenuation across the conterminous United States in the microseism frequency band. Sci Rep 2021; 11:10149. [PMID: 33980915 PMCID: PMC8115131 DOI: 10.1038/s41598-021-89497-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 04/27/2021] [Indexed: 11/09/2022] Open
Abstract
Mapping variations in the attenuation of seismic energy is important for understanding dissipative mechanisms in the lithosphere, and for modeling ground shaking associated with earthquakes. We cross-correlate ambient seismic signal recorded across the EarthScope Transportable Array in the 3–15 s period range. We apply to the resulting cross correlations a new method to estimate lateral variations in Rayleigh-wave attenuation, as a function of period, beneath North America. Between 3 and 6 s, our maps are dominated by a strong eastward decrease in attenuation. This pattern vanishes at longer periods, confirming early observations based on regional earthquakes. Attenuation maps and phase-velocity maps are anti-correlated at periods between 3 and 6 s, but the anti-correlation is also largely lost at longer periods. This corresponds to the attenuation coefficient decreasing with period more rapidly in the west than in the east, while the change in phase velocity with period is more uniform across the continent. Our results point to a transition in the properties of upper-crustal materials with depth, probably related to the closure of fluid-filled cracks and pores, and imply that measures of attenuation from seismic noise carry significant information on crustal rheology.
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Affiliation(s)
- Fabrizio Magrini
- Department of Sciences, Università degli Studi Roma Tre, Rome , Italy. .,Institute of Geosciences, Johannes Gutenberg University, Mainz, Germany.
| | - Lapo Boschi
- Dipartimento di Geoscienze, Università degli Studi di Padova, Padua, Italy.,Sorbonne Université, CNRS, INSU, Institut des Sciences de la Terre de Paris, Paris, France.,Istituto Nazionale di Geofisica e Vulcanologia, Bologna, Italy
| | - Lucia Gualtieri
- Department of Geophysics, Stanford University, Stanford, CA, USA
| | - Vedran Lekić
- Department of Geology, University of Maryland, College Park, MD, USA
| | - Fabio Cammarano
- Department of Sciences, Università degli Studi Roma Tre, Rome , Italy
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9
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Kim D, Lekić V, Ménard B, Baron D, Taghizadeh-Popp M. Sequencing seismograms: A panoptic view of scattering in the core-mantle boundary region. Science 2020; 368:1223-1228. [PMID: 32527827 DOI: 10.1126/science.aba8972] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 05/04/2020] [Indexed: 11/03/2022]
Abstract
Scattering of seismic waves can reveal subsurface structures but usually in a piecemeal way focused on specific target areas. We used a manifold learning algorithm called "the Sequencer" to simultaneously analyze thousands of seismograms of waves diffracting along the core-mantle boundary and obtain a panoptic view of scattering across the Pacific region. In nearly half of the diffracting waveforms, we detected seismic waves scattered by three-dimensional structures near the core-mantle boundary. The prevalence of these scattered arrivals shows that the region hosts pervasive lateral heterogeneity. Our analysis revealed loud signals due to a plume root beneath Hawaii and a previously unrecognized ultralow-velocity zone beneath the Marquesas Islands. These observations illustrate how approaches flexible enough to detect robust patterns with little to no user supervision can reveal distinctive insights into the deep Earth.
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Affiliation(s)
- D Kim
- Department of Geology, University of Maryland, College Park, MD 20742, USA.
| | - V Lekić
- Department of Geology, University of Maryland, College Park, MD 20742, USA
| | - B Ménard
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218, USA
| | - D Baron
- School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978, Israel
| | - M Taghizadeh-Popp
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218, USA
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10
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Irving JCE, Cottaar S, Lekić V. Seismically determined elastic parameters for Earth's outer core. Sci Adv 2018; 4:eaar2538. [PMID: 29963624 PMCID: PMC6021139 DOI: 10.1126/sciadv.aar2538] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 05/18/2018] [Indexed: 06/08/2023]
Abstract
Turbulent convection of the liquid iron alloy outer core generates Earth's magnetic field and supplies heat to the mantle. The exact composition of the iron alloy is fundamentally linked to the processes powering the convection and can be constrained by its seismic properties. Discrepancies between seismic models determined using body waves and normal modes show that these properties are not yet fully agreed upon. In addition, technical challenges in experimentally measuring the equation-of-state (EoS) parameters of liquid iron alloys at high pressures and temperatures further complicate compositional inferences. We directly infer EoS parameters describing Earth's outer core from normal mode center frequency observations and present the resulting Elastic Parameters of the Outer Core (EPOC) seismic model. Unlike alternative seismic models, ours requires only three parameters and guarantees physically realistic behavior with increasing pressure for a well-mixed homogeneous material along an isentrope, consistent with the outer core's condition. We show that EPOC predicts available normal mode frequencies better than the Preliminary Reference Earth Model (PREM) while also being more consistent with body wave-derived models, eliminating a long-standing discrepancy. The velocity at the top of the outer core is lower, and increases with depth more steeply, in EPOC than in PREM, while the density in EPOC is higher than that in PREM across the outer core. The steeper profiles and higher density imply that the outer core comprises a lighter but more compressible alloy than that inferred for PREM. Furthermore, EPOC's steeper velocity gradient explains differential SmKS body wave travel times better than previous one-dimensional global models, without requiring an anomalously slow ~90- to 450-km-thick layer at the top of the outer core.
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Affiliation(s)
| | - Sanne Cottaar
- Department of Earth Sciences, University of Cambridge, Cambridge, UK
| | - Vedran Lekić
- Department of Geology, University of Maryland, College Park, MD 20742, USA
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11
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Affiliation(s)
- Maxwell L Rudolph
- Department of Geology, Portland State University, Post Office Box 751, Portland, OR 97207, USA.
| | - Vedran Lekić
- Department of Geology, University of Maryland, College Park, MD 20742, USA
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