Paleoseismogenic dislocations in the Upper Kerulen basin (southern Henteyn-Daurian mega-arch)

In recent years, the Hustai, Gunji, and Kerulen paleoseismogenic structures have been discovered and examined within the Henteyn uplift. Their investigations revealed zones of probable earthquake foci, presenting a seismic hazard for Ulaanbaatar. We report the first data on the quantitative parameters of prehistoric earthquakes in the Meso-Cenozoic Upper Kerulen basin. The absolute age of two paleoevents determined by radiocarbon dating is within 1152–1702 BC and 5466–7201 BC. Seismogeological study of dislocations made it possible to estimate the type of tectonic stress during the formation of structures within the Henteyn uplift and to explain their nature. The horizontal-compression stress is mostly due to endogenous processes, which lead to the enlargement of the uplift area at the expense of the peripheral Mesozoic sedimentary basins.