摘要
通过解释反射地震剖面,计算处理重磁资料,数学模拟构造应力场以及综合分析其它地质、地球物理资料可知,冲绳海槽是一个正在活动的弧后盆地,具有高热流、强地震、多火山、薄地壳、高重力、活断层等特征。海槽内发育了两组断裂构造,其中NW向断裂是具有分割控制作用的特殊断裂,NNE向断裂是梨形正生长断层;两组断裂从中新世活动至现代。
In order to study faulting of the Okinawa Trough,this paper,based on interpretation of seismic data,comprehensively discusses submarine land-form,volcanism,earthquake and heat flow,and does gravitational calculation by means of spectrum analysis,smooth filter,analytic extension,horizontal derivative,correlative analysis and recalculating Moho.Meanwhile,mathematic simulation of regional tectonic stress field is also made.From the data mentioned above,some conclusions are obtained as follows.1.The Okinawa Trough is an active back-arc spreading basin characterized by high heat-flow,strong earthquake,strong volcanism,thin crust,high gravity anomaly and active fault.2.Two groups of fault are developed,which control the tectonic evolution of the Okinawa Trough.3.The fracture striking in NW direction has three features:(1)Equidistant distribution;(2)Multi-stage activity;(3)Dividing and controlling the independently developed fault blocks of the trough.4.The longitudinal faults in NNE strike with tension feature belong to listric normal contemporaneous ones which can illustrate the mechanism of trough spreading and crustal thinning.5.According to forming time,the faults may be divided into three stages.The first one took place at the end of Miocene and became the basement faults.The second occurred at the end of Pliocene in which some shallow faults are formed.And the last one is at the present in which the active faults brought forth the fault land-form at the bottom of Okinawa Trough.
作者
李乃胜
Li Naisheng(Institute of Oceanology,Academia Sinica,Qingdao)
出处
《海洋与湖沼》
1988年第4期347-358,共12页
Oceanologia Et Limnologia Sinica
