Tectonic Geomorphology and Paleoseismology of the Sharkhai fault: a new source of seismic hazard for Ulaanbaatar (Mongolia)

Abstract. We present first constraints from tectonic geomorphology and paleoseismology along the newly discovered Sharkhai fault near capital city of Mongolia. Detailed observations high-resolution Pleiades satellite images field investigations allowed us to map in detail, describe its geometry segmentation, characterize kinematics, document recent activity seismic behavior (cumulative displacements paleoseismicity). The displays a surface length ∼ 40 km with slightly arcuate geometry, strike ranging N42 N72∘. It affects numerous drainages that show left-lateral cumulative reaching 94 m. Paleoseismic faulting depositional/erosional events for last 3000 years reveal most event occurred between 775 1778 CE penultimate earthquake 1605 835 BCE. resulting time interval 2496 ± 887 is constraint large earthquakes. On basis our mapping rupture segmentation analysis, we propose two possible scenarios earthquakes likely magnitudes 6.7 0.2 or 7.1 0.7. Furthermore, apply scaling laws infer coseismic slip values derive preliminary estimates long-term rates. Finally, these data help build comprehensive model active faults region should be considered hazard assessment Ulaanbaatar.