GPR Measurements to Assess the Fault’s Characteristics in a Highly Smooth Topographic Context

Abstract

The seismic activity observed in the vicinity of Ulaanbaatar (UB) city not only has been increased since 2005, but it is also well organized, at least, on two perpendicular active faults: Emeelt fault (40 km, 15 km NW of UB) and Hustai fault (80 km, 30 km West of UB). Their morphology indicates they are capable to produce earthquakes of magnitude 6.5 to 7.5. Most of the Mongolian population (1.5 over 3 million) is concentrated around UB city. Hence, the study of seismic hazard is of first importance for the country. In addition to seismotectonic and magnetic studies, we have conducted two GPR campaigns (2010 and 2011), in order to characterize these faults. In our study we present the 2D and 3D GPR measurements performed along the Emeelt fault. Since the last large earthquake, the geomorphology has been highly smoothed by erosion processes and low slip rate (very likely less than 1mm per year), and the location of the fault plane is estimated in a several meters strip. The cumulate displacement on this fault is expected to be about one to several meters. I am a PhD student and would like to be considered for the AGAP-Quality Award.