First observations of core-Transiting seismic phases on Mars

Jessica C.E. Irving, Vedran Lekic, Cecilia Durán, Mélanie Drilleau, Doyeon Kim, Attilio Rivoldini, Amir Khan, Henri Samuel, Daniele Antonangeli, William Bruce Banerdt, Caroline Beghein, Ebru Bozdagk, Savas Ceylan, Constantinos Charalambous, John Clinton, Paul Davis, Raphaël Garcia, Domenico Giardini, Anna Catherine Horleston, Quancheng HuangKenneth J. Hurst, Taichi Kawamura, Scott D. King, Martin Knapmeyer, Jiaqi Li, Philippe Lognonné, Ross Maguire, Mark P. Panning, Ana Catalina Plesa, Martin Schimmel, Nicholas C. Schmerr, Simon C. Stählerc, Eleonore Stutzmann, Zongbo Xu

Research output: Contribution to journalArticlepeer-review


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.

Original languageEnglish (US)
Article numbere2217090120
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number118
StatePublished - May 2 2023
Externally publishedYes


  • Mars
  • core evolution
  • planetary structure

ASJC Scopus subject areas

  • General


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