Preliminary Assessment of the Morphometry of Martian Impact Crater Ejecta Deposits and their Implications,

We are continuing characterization of the geometry of flow-related features of the fluidized ejecta of fresh Martian craters to be used in concert with dynamical models of granular flow as a basis for developing new models and testing current models of fluidized ejecta emplacement. Granular flow studies have shown great promise for understanding the causes of ejecta flow on Mars [1, 2] because 1) the fragmental nature of ejecta [3] makes ejecta, by definition, a granular flow, and 2) recent major advances in granular flow dynamics have been made in understanding rapidly moving granular materials. Below we briefly discuss examples of features being studied, including radial structures, secondary crater, transverse structures, and ramparts. Radial Structures: Radial furrows and ridges are common on ejecta deposits of all types of fluidized ejecta craters (Figures 1). They