Geometry and segmentation of Cerberus Fossae, Mars: implications for marsquake properties.

Le résumé fourni par la source

The NASA InSight mission to Mars successfully landed on November 26 th , 2018 in Elysium Planitia. It aims to characterize the seismic activity and constrain the internal structure of Mars. We focus on the Cerberus Fossae region, a giant fracture network of ~1200 km long situated east of the InSight landing site, and where M~3 marsquakes were detected during the past two years. It is formed of five main fossae located on the southeast of the Elysium Mons volcanic rise. We perform a detailed mapping of the entire system based on high resolution satellite images and Digital Elevation Models. The refined cartography reveals a range of morphologies associated with dike activities at depth. Width and throw measurements of the fossae are linearly correlated, suggesting a possible tectonic control on the shapes of the fossae. Widths and throws decrease toward the east, indicating the long-term direction of propagation of the dike-induced graben system. They also give insights into the geometry at depth and how the possible faults and fractures are rooted in the crust. The exceptional preservation of the fossae allows us to detect up to four scales of segmentation, each formed by a similar number of 3-4 segments/subsegments. This generic distribution is comparable to continental faults and fractures on Earth. We anticipate higher stress and potential for marsquakes within intersegment zones and at graben tips.

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