COSEISMIC SURFACE RUPTURES OF MULTI SEGMENTS AND SEISMOGENIC FAULT OF THE TASHKORGAN EARTHQUAKE IN PAMIR,1895

Based on the interpretation of satellite images,combined with field geomorphic and tectonic investigations and surveys,we get the parameters of surface rupture zones of the 1895 Tashkorgan earthquake,such as the geometry,the types of rupture,the displacements and their distribution and so on.And on these grounds,we estimate the possible magnitude,the epicenter and seismogenic fault of this earthquake.The south segment of Muztag Fault and the whole Taheman Fault were ruptured by the Tashkorgan earthquake.The length of the surface rupture zone is 27km.The rupture zone strikes NNE,and it changes from N25°W in the north to N25°E in the south segment.The surface rupture zone is composed of consequent or obsequent normal fault scarps,represented by horst,graben,and step-like structure on the profile,and distributed in patterns as en echelon,parallel,convergent and parallel cross shaped and so on in the plane.The surface ruptures are dominated by pure dip-slip,with little lateral displacement.The general width of these overlapping surficial fault rupture strands is ca.30～60m,and the largest may come to 825m.The largest co-seismic displacement of a single scarp is 4.2±0.2m.The surface ruptures are composed of three independent secondary segments.The seismogenic fault of this earthquake is Taheman Fault.The south segment of Muztag Fault was also ruptured.Moreover,we find a younger fault scarp which may be induced by the 1895 earthquake in the small basin between the two above-mentioned faults.