It is well known that studies on palaeo-seismicity at present are generally accomplished byanalyzing the scale and episode of wedge-shaped seismic colluvial deposits along fault zones. Asan example,this paper has inve...It is well known that studies on palaeo-seismicity at present are generally accomplished byanalyzing the scale and episode of wedge-shaped seismic colluvial deposits along fault zones. Asan example,this paper has investigated the seismic landslides along the Changma fault zone, analyzed their modes of combination, intrinsic structural characteristics and ages,and thereby studied palaeo-seismic events on that fault zone.The Changma fault zone is an important active fault zone in the northwest of the Qilianmountains. It trends about west-northwest on the whole, and is composed of west-northwest,east-northeast-and n ort h-nort h west-ire nd in g fan its. It w as form ed in t h e Ca led onia n p eriod ofthe Palaeozoic era and had had obvious activities in all of the Hercynian, Yanshan and Himalayanperiods. DUring the Quaternary period, especially in the late Pleistocene, it has experiencedmany times of intense left-lateral strike-slip movements. The Changma Ms￣7. 5 earthquake occurred on December 25, 1932, and produced a series of seismic landslides and collapses alongpiedmont areas of the basement fault (Figure la).展开更多
An M 8.1 earthquake that occurred west of the Kunlun Mountains Pass has caused more than 20 collapse bodies or zones, which are mainly distributed near the surface seismic rupture zone, west of Hoh Sai Lake. The colla...An M 8.1 earthquake that occurred west of the Kunlun Mountains Pass has caused more than 20 collapse bodies or zones, which are mainly distributed near the surface seismic rupture zone, west of Hoh Sai Lake. The collapses are of four types, bedrock, soil mass and ice mass collapses and avalanches. The spatial distribution and the characteristics of development of the collapses are analyzed in the paper. Comparised with those caused by other earthquakes, the collapses are smaller in scale. In addition to the lithological characteristics of the crustal media, topographic, geomorphic and climatic factors, weaker seismic ground motion is an important cause for formation of the smaller-scale collapses. The long surface rupture zone and weaker ground motion are important features of the seismic rupture, which may be related to the structure of the preexisting fault.展开更多
文摘It is well known that studies on palaeo-seismicity at present are generally accomplished byanalyzing the scale and episode of wedge-shaped seismic colluvial deposits along fault zones. Asan example,this paper has investigated the seismic landslides along the Changma fault zone, analyzed their modes of combination, intrinsic structural characteristics and ages,and thereby studied palaeo-seismic events on that fault zone.The Changma fault zone is an important active fault zone in the northwest of the Qilianmountains. It trends about west-northwest on the whole, and is composed of west-northwest,east-northeast-and n ort h-nort h west-ire nd in g fan its. It w as form ed in t h e Ca led onia n p eriod ofthe Palaeozoic era and had had obvious activities in all of the Hercynian, Yanshan and Himalayanperiods. DUring the Quaternary period, especially in the late Pleistocene, it has experiencedmany times of intense left-lateral strike-slip movements. The Changma Ms￣7. 5 earthquake occurred on December 25, 1932, and produced a series of seismic landslides and collapses alongpiedmont areas of the basement fault (Figure la).
基金TheresearchwassupportedunderakeyScienceandTechnologyResearchProjectoftheScienceandTechnologyDepartmentofQinghaiProvince (2 0 0 2 N 14 1),China
文摘An M 8.1 earthquake that occurred west of the Kunlun Mountains Pass has caused more than 20 collapse bodies or zones, which are mainly distributed near the surface seismic rupture zone, west of Hoh Sai Lake. The collapses are of four types, bedrock, soil mass and ice mass collapses and avalanches. The spatial distribution and the characteristics of development of the collapses are analyzed in the paper. Comparised with those caused by other earthquakes, the collapses are smaller in scale. In addition to the lithological characteristics of the crustal media, topographic, geomorphic and climatic factors, weaker seismic ground motion is an important cause for formation of the smaller-scale collapses. The long surface rupture zone and weaker ground motion are important features of the seismic rupture, which may be related to the structure of the preexisting fault.
