论文部分内容阅读
发育在北天山山麓的活动断裂褶皱带属于向前扩展的薄皮构造，且所有的背斜都是断裂扩展褶皱，主滑脱面距地表8～9km深。距今292万年以来，地壳缩短13．5～14．6km，缩短率是4.62～5．0mm／a。自30000年前至今，准噶尔南缘断裂和齐古道断裂褶皱带的活动十分微弱，而独山子和玛纳斯道断裂-褶皱带则是活动褶皱-断裂带。北天山地区普遍发育三级阶地,受活动逆断裂和褶皱的影响，均产生褶曲变形和错断。距今12000～13000年以来，吐谷鲁逆断裂-背斜的垂直滑动速率、抬升速率、缩短速率分别是0．83～0．91、3.46～3.75和1.23～1．33mm／a。1906年的玛纳斯地震发生在一条盲断坡上，但是其同震破裂和褶皱隆升却出现在玛纳斯逆断裂-褶皱带上，震中距玛纳斯逆断裂-褶皱带约40km。揭示出北天山挤压拗陷区的孕震构造是一个由深部盲断坡-滑脱断层-浅层断坡构成的复杂构造系统。通过上述活动构造和古地震研究的结果可以推测，天山北麓未来发生大震（M≥7．0）的位置可能是在呼图壁河至金沟河段和金沟河至奎屯河段的齐古道断裂-褶皱带上，其震级相当于1906年玛纳斯地震。乌鲁木齐挤压坳陷中的活动逆断裂褶皱带上只有发生M≤6．0地震的可能性。
The active fault fold belt developed at the foothills of the North Tianshan Mountains belongs to a thin-skinned structure with an anterior extension. All anticlines are fault-expanding folds, and the main slip surface is 8 to 9 km deep from the surface. Since 2.92 million years ago, the crust has been shortened by 13.5 ~ 14.6km, the shortening rate is 4.62 ~ 5.0mm / a. Since 30000 years ago, the activities of the southern margin of Junggar and the fold belt of the Qigedao fault have been very weak, while the fault-fold belt of the Dushanzi and Manasdao faults has been active fold-fault zone. The northern Tianshan area generally develops three terraces, which are subject to fold deformation and fault due to the action of reverse faults and folds. Since 12000 ~ 13000 years ago, the vertical sliding rate, lifting rate and shortening rate of the Tugulu reverse fault - anticline are respectively 0.83 ~ 0.91, 3.46 ~ 3.75 and 1.23 ~ 1.33mm / a. The Manas earthquake of 1906 occurred on a blind slope, but its coseismic rupture and fold uplift occurred on the Manas thrust-fold belt with a distance of about 40 km from the Manas thrust-fold belt. It is revealed that the seismogenic structure of the North Tianshan extrusion-depression region is a complicated structural system composed of deep blind fault-slip fault-shallow fault. Based on the results of the above tectonics and paleoearthquakes, it is speculated that the future occurrence of a large earthquake (M≥7.0) at the northern foot of the Tianshan Mountains might be located between the Hutubi River and Jingou River and the Jingouhe River to the Kuitun River The Qi Gudao fault - fold belt, its magnitude is equivalent to the 1906 Manas earthquake. Only the M≤6.0 earthquake is likely to occur on the active reverse fault fold belt in the Urumqi squeezed depression.