Tectonic interpretation of active fault extending in Myanmar, Laos and China by relief map of ASTER GDEM and harmonized geological map

In 24 March 2011, an earthquake on the scale of Mw 6.8 occurred at the west end of the Nam Ma Fault, which is 215 km long, crossing Myanmar, Laos and China. The rupture occurred on a 30 km-long segment in Myanmar. The earthquake was limited to individual segments, reducing its magnitude. The ASTER GDEM is accessible from a download site. Its relief map illustrates linear features reflecting fault scarps, step-overs, pull-apart areas and bends associated with tectonic deformation. A harmonized geological map of the study area that was continuous over the cross-border areas was compiled. The map reveals lithologies, ages of formations, continuous displacement lines and exotic terranes. Intensive field surveys provided information on tectonics in Myanmar while on the Laos side intensive surveys were not conducted. The ASTER GDEM data and the harmonized geological maps were used to support mapping of the entire segmentation of the Nam Ma Fault. The mapped Nam Ma Fault consists of five segments. Estimated slip-plane areas and magnitudes of possible earthquakes of the respective segments indicate that the greatest magnitude is 7.3 in the case of rupture of a 100 km long segment.