盲断裂、褶皱地震与新疆1906年玛纳斯地震

BLIND THRUST，FOLDING EARTHQUAKE，AND THE 1906 MANAS EARTHQUAKE，XINJIANG

１９０６年玛纳斯７．７级地震时沿准噶尔南缘断裂产生的地表破坏是由非构造成因的振动和重力效应而形成的。天山山前第二排逆断裂和褶皱带是这次地震的发震构造，沿带已发现了长约１３０ｋｍ的断续的地表破裂和最新隆起带。所以１９０６年玛纳斯地震是沿北天山主逆断裂带发生在深部的一次盲断裂地震。地表变形主要以褶皱隆起为主，是一次典型的“褶皱地震”。

The 1906 Manas earthquake is an important event in the northern Tianshan of China. TheSeismogenic fault controlling this earthquake has not been well understood． Detailed field investi-gation indicates that the ground ruptures in the epicentral area were caused by gravitational andshaking effects during the earthquake. The fresh fault scarps along the Tugulu-Manas-Houer-goush reverse fault and fold zone are the possible surface ruptures associated with the 1906 Manasearthquake. The displacement is between 0．2 and 0．5m. Total length of the fault scarp is lessthan 10 km which is far more less than a normal rupture length associated with an earthquake ofmagnitude7．7．Anticlinal uplifting along this reverse fault and fold zone indicates that the earth-quake probably occurred along low-angle reverse fault at depth as a blind reverse faulting event.The surface rupture and deformation took place far away from the epicentral area. Most of thecoseismic deformation was accomodated by folding and uplifting，and only less than 10 km sur-face rupture was formed．Thus，the 1906 Manas earthquake is probably a“folding earthquake”.