关键词: 渭河盆地, 秦岭北麓, 断层陡坎, 古地震

Abstract: Interpretation of aerophotoes and field investigation make authors find that a series of fault scarps are distributed in the .unconsolidated Quaternary sediments on the northern piedmont of Qinling Mts. Further geological,geomorphological and chronological studies of the fault scarps in combination with the analysis of levelled morphological sections of the scarps and excavated trenches led us to reveal the spatial distribution,geometric features,ages and offsets of the fault scarps and the activity of the northern piedmont fault of Qinling Mountain in late Quatery. It is indicated that the fault scarps occurred and were preserved on special tectonic and geomorphic parts of the zone. The heights of the scarps range from 1.1m to 7.7m,but the scarps on elder morphological surfaces are higher than those on younger morphological surfaces. The average slip rate along the middle segment of the northern piedmont fault in late Holocene is about 1mm/a,while that along the western segment of the fault is about 0.5mm/a. Three or four large paleoseismic events probably occurred on the northern piedmont fault since late Pleistocene.

Key words: Weihe Basin, Northern piedmont of Qinling Mts, Fault scarps, Paleoearthquakes