Abstract:

The fault scrap collapse wedge is the direct result of fault activity, it is also signification of paleoearthquake events, its accurate dating is the key to solve the problems about paleoearthquake events.Luminescence techniques are rapidly progressing in recent years.Simplified multiple aliquot regenerative-dose (SMAR) protocol is already applied successfully in loessial sediments after 130 ka.The studied samples are collected detailedly in two fault scarp collapse wedges(D1 and D2) from the schematic section of Nanyukou in north piedmont zone of Wutai Mountain in Xinding basin, Shanxi Province.The sample ages are acquired with fine grain quartz (4-11 μm) SMAR protocol.The results of the OSL dating show that evolutional models of D1 and D2 are different from general model of normal fault collapse wedge.The palaeotopography of D1 is formed by accumulating nearby the fault to stretch out far, whereas the palaeotopography of D2 is formed by accumulating horizontally and is thicker than D1.After dilapidation powerful current has rised in D1. The results indicate that the older paleoearthquake event occurred between (42.77±2.46) ka and (61.72±2.82) ka, the younger paleoearthquake event occurred between (3280±287) ka and (47.92±0.94) ka.The interval of the two paleoearthquake events is between 10 ka and 15 ka.

Key words: Xinding basin, north piedmont zone of Wutai Mountain, fault collapse wedge, SMAR, OSL dating