关键词: 地震形变特征, 壳幔界面陡变带, 发震模式

Abstract: The Tuotegongbaizi-Aerpaleike fault is located in the epicentral area of the 1902 Artux,Xinjiang earthquake of M S 81/4. It is a gently dipping reverse fault, merging downward into the decollement of South Tianshan Foreland Thrust belt at about 3km depth below the Earth surface. To the north of the epicentral area, lies the Muziduke thin-skinned arcuate nappe of the South Tianshan Foreland Thrust belt, while to the south lies the Mushi-Kashi-Artux arcuate recoil fold-thrust belt of northwest Tarim. The epicentral area is just located at the triangle zone of frontal structure of the juncture between these two major tectonic units. In the epicentral area a deep fault exists under the decollement of the thin-skinned nappe, extending downward to the Moho. It is located at the sharp gradient zone of the crust-mantle boundary between the South Tianshan and the Tarim basin. The projection of epicenter falls at a zone of abrupt change of crustal thickness. It seems that this great earthquake was the result of rapid faulting at the gradient zone of the crust-mantle boundary due to the action of N-S trending regional tectonic stress field. Because the focal depth is great, no earthquake faulting is observed on the surface. The deformation of the magistoseismic area is characterized mainly by physicogeologic phenomena such as collapse, landslides, and ground-fissures, accompanied by coseismic ruptures and folding of the active thin-skinned structures above the decollement.

Key words: Seismic rupture, Gradient zone of crust-mantle boundary, Seismogenic model