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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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