Geometry and segmentation of Cerberus Fossae, Mars: implications for
marsquake properties.
Abstract
The NASA InSight mission to Mars successfully landed on November
26th, 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.