北天山地区活动逆断裂-褶皱带构造与潜在震源区估计

ACTIVE REVERSE FAULT FOLD ZONES AND ESTIMATION OF POTENTIAL EARTQHUAKE SOURCES IN NORTHERN TIANSHAN

北天山山前逆断裂－褶皱带是典型的大陆内部活动挤压构造，该地区的地表活动构造、隐伏活动构造及活动背斜都受地下深处近水平滑脱断层控制。对１９０６年玛纳斯地震（Ｍ７．７）的发震构造、地表变形与破裂特征和山前活动逆断裂带上古地震的研究表明，北天山山前隐伏活动深断坡具备大地震发生的构造条件，大致以金钩河为界分为东西两段，相应地构成两个大地震潜在震源（Ｍ８）。山前第２条玛纳斯逆断裂－褶皱带和第３条独山子逆断裂－褶皱带中的各个活动背斜，以及西湖隆起等可能是８个中强地震的潜在震源（Ｍ６）。

The reverse fault fold zones in the foreland basin of northern Tianshan is a typical active compression area in interior of continents. The research of the surface and deep structure, and its relationship in the active compression tectonic region is extremely important for the understanding its seismogenic structure and dividing its potential earthquake sources. On the basis of detailed research on the major active tectonics and synthetical studies in northern Tianshan, the deformation of the structure, earthquakes and active tectonics, and the relationship between surface and deep structures have been discussed in this paper. Finally, a few questions have been put forward in the process of potential earthquake source dividing in the active compression tectonic belt. Based on the research of the 1906 Manas earthquake ( M 7.7) and paleoearthquakes on the active reverse faults, we can know that the blind active crust ramp under the piedmont in the northern Tianshan area is the place of large earthquake occurring, and divided the blind ramp into two segments at the Jinguohe area. The active blind crust ramp may have two large potential earthquake ( M 8.0) sources. There are eight active anticlines in the northern Tianshan, west Urumqi. We can also compare these active anticlines with the active folds in the west region of the United States of America, and conclude that these active anticlines can only produce some middle earthquakes ( M 6.0). All the active anticlines in the northern Tianshan, west Urumqi, may have eight potential earthquake sources.