Interpreting SHARAD radargrams using interaction models and geological constraints to study faults zones

Introduction: SHARAD (SHAllow RADar) is a radar sounder capable of discriminating layers of different materials in the martian crust. Both its vertical resolution and discrimination capabilities depends on layer relative permitivitty. Therefore, SHARAD is in principle not only able to detect subsurface layers of liquid water and ice, but also some aspects of vertical structure of the Martian crust. The objective of this work is to present evidence of the SHARAD capabilities to retrieve information about the structure of a fault zone located at North-East of Ismeniae Fossae. To this end, we will use SHARAD data of the area, a Lee based adaptive filter and interaction model to interpret radargram structure. Geological setting: Interpreted radargram is located at North-East of Ismeniae Fossae. In order to analyze a fault zone, we have specially chosen the studied radargram from several ones, taking in account either its physiographic location and its geological setting. Despite we analysed others radargrams located in undoubtedly faults areas, like Thaumasia region or Tempe Fossae, we discarded them since its topographic complexity add a lot of noise to the radargrams. As can be seen in figure 1, we chose a radargram that pass through a simple linear scarp. The straight morphology of the scarp and its association with nearby polygonal craters, which linear rims are parallel to the studied scarp [1, 2], implies that is structurally controlled. Moreover the radargram is just in the contact between Nn and HNn units from Tanaka et al. [3].