摘要
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 activefault－foldzonesareforward－propagatedthin－skinnedstructure；and all anticlines along the northern Tianshan piedmont are fault－propagation folds．The main detachment is located at depth of 8～9 km．The shortening amount and rate have been 13．5～14．6 km and 4．62～5．0 mm／a since 2．92 MaB．P， respectively．The southern marginal fault of Jungeer Basin and Qigu reverse fault－fold zones have become inactive since 30000 years B．P， Dushanzi and Manas reverse fault－fold zones are active．Three terraces，the ages of which are 60 000～70 000，12 000～13 000，and 7 000～8 000 years B．P，haVe been folded and cut by active reverse faults．Since 12 000～13 000years B．P， the vertical slip，uplift．and shortening rates of Tugulu reverse faultfold anticline are 0．83～0．91，3．46～3．75，and3．0～3．25 mm／a，respectively，and those of the Dushanzi reverse fault－fold anticlineare 0．77，1．92～2．08，and 1．23～1．33mm／a，The 1906 Manas earthquake occurred at a blind ramp，but the coseismic ruptures and uplift are found along the Manas reverse fault－fold zone．The earthquake epicenter is about 40 km far from the Manas reverse fault－fold zone．This large earthquake shows that the selsmogenic tectonic model is adeep blind ramp－detachment－shallow ramp system in the depressional region． It Is reasonable to infer that the slies of large earthquakes（M≥ 7．0） which will occurs are located along the northern Piedment of Tianshan Mountains， i． e， the segment from the Hutublhe river to Jingouhe river and the segment from Jingouhe river to Kuitunhe river，equivalent to the magnitude of the 1906 Manas earthquake.The active reverse fault-foldzone in the Urumqi depression can only be pregnant with middle earthquakes（M≤6．0）.
出处
《内陆地震》
1997年第4期361-378,共18页
Inland Earthquake
