The Research of the Activity of the Piedmont Fault on the Tangshankou Segment of the Yuguang Basin Southern Marginal Fault

(整期优先)网络出版时间:2017-04-14
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TheYuguangbasinisahalf-grabenbasininthebasin-rangetectoniczoneinnorthwestBeijing,locatedatthenorthernendoftheShanxigrabensystem,andtheYuguangbasinsouthernmarginalfault(YBSMF)controlstheformationofthisbasin.AlinearfaultescarpmenthasformedintheproluvialfanonthepiedmontfaultzoneoftheTangshankousegmentofYBSMF.Atrenchacrossthisescarpmentrevealsthreepaleo-earthquakeeventsontwoactivefaults.Onefaultrupturedatabout9kaforthefirsttime,andthenfaultedagainatabout7.3ka,causingtheformationandsynchronousactivityofanotherfault.Finally,theyfaultedforthethirdtime,butwecannotdeterminethefaultingtimeduetothelackofrelevantsurfacedeposition.Theaccumulativeverticaldisplacementofthesethreeeventsisabout8.1m.Weestimatethattheaveragerecurrenceperiodofthepiedmontfaultisabout1.7ka,andtheaveragesliprateofthepiedmontfaultisabout1.6mm/a.Wealsoestimatethereferencemagnitudeofeacheventaccordingtotheempiricalformula.