Evidence of active tectonic activity in Muong Te area illuminated by geomorphic analysis

Abstract

Muong Te area is located in the northwest part of the Da River valley is seismically active with numerous recent earthquakes and associated geohazard as the consequences of tectonic collisions between the Indian plate and the Eurasian plate. The most dominant lineament system alogate in NW - SE trending which is about several kilometer to several ten kilometer. However, there has been little research regarding neotectonics deformation in this area. This study compiles remote sensing images observation data with new extracted geomorphic indices of the fluvial network to illustrate deformation patterns and potential active movements in the Muong Te. Previous study noticed that although river channels occupy a small part of the land surface, a longitudinal river profile is a more sensitive indicator of rock uplift rate than other morphological properties (Whipple et al. 2007; Dinh et al. 2019). Relationship between faults and geomorphology is quantified using 12.5 - m ALOS DEM to extract channel and basin metrics including drainage basin normalized steepness index (ksn) is greater than 200 (m0.9), and knickpoints of modeled river longitudinal profiles. The results of the normalized steepness index also show that several knickpoints arise locally from lithological boundaries of different erodibility; however, many high values of ksn the river were truncated by the NW - SE lineamets system which is suggesting that Da River fault system seem to be active. The results proposed that the strike - slip and normal motions alternated because of a permutation of σ1/σ2 under the same extensional stress regime of σ3 in the northeast - southwest direction. The existence of the active tectonics in the area might pose many geological hazards and it threat to regional habitants.