Tectonics of Cerberus Fossae unveiled by marsquakes
Résumé
The InSight mission has measured the seismicity of Mars since February 2019 and has enabled the investigation of tectonics on the surface of another planet for the first time. Its dataset shows that most of the widely distributed surface faults are not seismically active, and that seismicity is mostly originating from a single population of tectonic structures, the Cerberus Fossae. We show that the spectral character of deeper low-frequency marsquakes suggests a structurally weak, potentially warm source region consistent with recent magmatic activity at depths of 30-50 km. We further show that high-frequency marsquakes occur distributed along the Cerberus Fossae, in the brittle, shallow part, potentially in fault planes associated with the graben flanks. Together, these quakes release an annual seismic moment of 1.4-5.6 × 1015 N m yr−1 or at least half the seismicity of the entire planet. Our findings confirm that the Cerberus Fossae represents a unique tectonic setting shaped by current day magmatic processes and locally elevated heat flow.
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