Paper No. 178-6
Presentation Time: 9:00 AM-6:30 PM
DETERMINING CERES' SUBSURFACE ICE CONTENT THROUGH THE PROPERTIES OF INTERMEDIATE LANDSLIDES
DUARTE, Kayla1, SCHMIDT, Britney E.1, CHILTON, Heather1, FERRIER, Ken L.2, HUGHSON, Kynan H.G.3, SCULLY, Jennifer E.C.4, SIZEMORE, Hanna G.5, NATHUES, Andreas6, PLATZ, Thomas7, RUSSELL, C.T.8, RAYMOND, Carol A.4 and WRAY, James J.9, (1)School of Earth & Atmospheric Sciences, Georgia Institute of Technology, 311 Ferst Drive, Atlanta, GA 30332, (2)School of Earth and Atmospheric Sciences, Georgia Institute of Technology, 311 Ferst Drive, Atlanta, GA 30332, (3)Institute of Geophysics and Planetary Physics, University of California, Los Angeles, CA, (4)NASA Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, (5)Planetary Science Institute, 1700 East Fort Lowell, Suite 106, Tucson, AZ 85719-2395, (6)Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, Goettingen, 37077, Germany, (7)Max Planck Institute for Solar System Research, Göttingen, 37077, Germany, (8)Earth, Planetary and Space Sciences/IGPP, University of California, Los Angeles, 603 Charles Young Drive, 3845, Los Angeles, CA 90095, (9)School of Earth and Atmospheric Sciences, Georgia Institute of Technology, 311 Ferst Drive, Atlanta, GA 30332-0340, kduarte3@gatech.edu
Ceres, the largest body in the asteroid belt, is a primary focus of NASA’s Dawn mission, partially due to evidence for ice in Ceres’ surface and interior. Here we use Dawn Framing Camera data and build on earlier work using landslides to estimate ice content. Previously, three landslide types were identified using morphological criteria: type 1 (T1) have a thick, lobate toe, type 2 (T2) are thin and have a larger run out length than T1 landslides, and type 3 (T3) are more comparable to fluidized ejecta. However, landslides that do not fall cleanly into these groups, termed intermediate (IM), span a continuum between T1 and T2. Looking at these IM landslides allows us to better understand the relationship and progression between T1 and T2 and to identify any unique behaviors.
Our current analysis of IM landslides estimates the friction coefficient of Ceres’ near-surface material as the landslide deposit is emplaced via the ratio of landslide drop height to run-out length (H/L). We include both the conventional maximum (max) and our in-progress center of mass (CoM) approximation. To obtain HMax/LMax, we measure a topographic profile of the feature to attain its maximum length and height. HCoM/LCoM measurements are obtained using a profile by estimating the center of mass of the projected preexisting surface and the deposit. We have found some H/L values to be lower than those of landslides sourced in clay-rich materials, suggesting that the effective friction coefficient of these landslides is relatively low, potentially due to ice in the failed material. Further, the overlapping range of H/L ratios for T1 and T2 flows is reinforced by the continuous range of H/L values for IM landslides. This implies emplacement conditions are not uniquely linked to morphology, and may suggest temperature-dependent behavior. Overall, the major conclusions drawn from IM landslide analyses are 1) the idea that landslide mobility is loosely tied to morphology, and 2) that landslides on Ceres exhibit a continuous range of morphologies, with T1 and T2 representing end members of that continuum.
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