Application of Remotely Sensed Data for Neotectonics Study in Western Mongolia

Landsat TM and ASTER data were used in the neotectonics study of Western Mongolia. The latter has been one of the most seismically active intracontinental regions of the world in this century. The occurrences of earthquakes are mostly controlled by active faults. The relief in the area is remarkable due to its sharp contrasts and the multitude and variability of the morphological elements: high rugged mountains, basins, and wide hilly areas composed of loose sands, gravels and boulders. In an area such as this, where the morphology of the terrain responds to a cold, dry climate and where erosion is slow, fault ruptures cutting pediment surfaces are well preserved. Various geomorphic features supporting recent tectonic movements were deciphered from the various remotely sensed data. These include: strike-slip faults, fault line scarps, triangular facets, uphill facing scarps, pressure-ridges, abrupt change in topographic slope angles along fault traces, offset drainage, truncated fan and beheaded drainage. Most of these features were examined in the field and revealed movements that have occurred during the Holocene (past 10,000 years).