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Joint Inversion of receiver functions and apparent incidence angles to determine the crustal structure of Mars
  • +4
  • Rakshit Joshi,
  • Brigitte Knapmeyer-Endrun,
  • Klaus Mosegaard,
  • Mark A. Wieczorek,
  • Heiner Igel,
  • Ulrich Christensen,
  • Philippe Henri Lognonné
Rakshit Joshi
Max Planck Institute for Solar System Research

Corresponding Author:[email protected]

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Brigitte Knapmeyer-Endrun
Bensberg Observatory, University of Cologne
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Klaus Mosegaard
Niels Bohr Institute
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Mark A. Wieczorek
Observatoire de la Côte d'Azur
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Heiner Igel
Ludwig Maximilian University of Munich
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Ulrich Christensen
Max-Planck-Institut für Sonnensystemforschung
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Philippe Henri Lognonné
Institut de Physique du Globe de Paris et Université de Paris Diderot
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Abstract

Recent estimates of the crustal thickness of Mars show a bimodal result of either ∼20 km or ∼40 km beneath the InSight lander. We propose an approach based on random matrix theory applied to receiver functions to further constrain the subsurface structure. Assuming a spiked covariance model for our data, we first use the phase transition properties of the singular value spectrum of random matrices to detect coherent arrivals in the waveforms. Examples from terrestrial data show how the method works in different scenarios. We identify three new converted arrivals in the InSight data, including the second multiply reflected phase from a deeper third interface. We then use this information to jointly invert receiver functions with the absolute S-wave velocity information in the polarization of body waves. Results show a crustal thickness of 43±5 km beneath the lander with two mid-crustal interfaces at depths of 8.5±1.5 km and 22±3 km.