Constraints on mechanisms for the growth of gully alcoves in Gasa crater, Mars, from two-dimensional stability assessments of rock slopes

Icarus
By: , and 

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Abstract

The value of slope stability analyses for gaining insight into the geologic conditions that would facilitate the growth of gully alcoves on Mars is demonstrated in Gasa crater. Two-dimensional limit equilibrium methods are used in conjunction with high-resolution topography derived from stereo High Resolution Imaging Science Experiment (HiRISE) imagery. These analyses reveal three conditions that may produce observed alcove morphologies through slope failure: (1) a ca >10m thick surface layer that is either saturated with H2O ground ice or contains no groundwater/ice at all, above a zone of melting H2O ice or groundwater and under dynamic loading (i.e., seismicity), (2) a 1-10m thick surface layer that is saturated with either melting H2O ice or groundwater and under dynamic loading, or (3) a >100m thick surface layer that is saturated with either melting H2O ice or groundwater and under static loading. This finding of three plausible scenarios for slope failure demonstrates how the triggering mechanisms and characteristics of future alcove growth would be affected by prevailing environmental conditions. HiRISE images also reveal normal faults and other fractures tangential to the crowns of some gully alcoves that are interpreted to be the result of slope instability, which may facilitate future slope movement. Stability analyses show that the most failure-prone slopes in this area are found in alcoves that are adjacent to crown fractures. Accordingly, crown fractures appear to be a useful indicator of those alcoves that should be monitored for future landslide activity. ?? 2010.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Constraints on mechanisms for the growth of gully alcoves in Gasa crater, Mars, from two-dimensional stability assessments of rock slopes
Series title Icarus
DOI 10.1016/j.icarus.2010.09.025
Volume 211
Issue 1
Year Published 2011
Language English
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Icarus
First page 207
Last page 221