关键词: 断层活动, 力学模拟, 第四纪

Abstract: Shabanliang ridge is a new uplift in the middle part of Datong basin and lies in an extensional environment.It is NE-trending and 60km long.Its bed rock is gneiss and is covered with Quaternary unconsolidated sedimentary layers,which include clay layers,fine-coarse sand layers gravel layers and loess layers.On the Shabanliang ridge there is a series of active normal faults in these unconsolidated layers.After field investigation,mechanical experiments in field and in laboratory to simulate behavior of active faults,the characeristics and types of the active structures on Shabanliang uplift are studied in this pater.The active sturctures,especially their extra ordinary pressentation forms in Quaternary unconsolidated sedimentary layers,are studied in detail,in order to find effective identification markers of active faults in Quaternary unconsolidated sedimentary layers.There are two kinds of active faults in general:visible and non-visible faults.The visible active faults can be divided into three types and the non-visible active faults can be recognized into four types.The difference between different types of faults is due to the difference in quality of sedimentary layers and forcing mode.By simulation experiments the influence of forcing mode (forcing slowly and rapidly) on sedimentary layers is analysed.These are very important to determine the most recent rupture time of active faults and how they are distributed in unconsolidated layers.By more precisely justifying the latest faulting,we can find the cycle of paleoseismic events more accurately and hence to evaluate the earthquake risk in engineering geology and to predict the possibility of earthquak.

Key words: Faulting, Mechanical, simulation, Quaternary