论文部分内容阅读
通过在上海地区开展深、浅地震反射、地震宽角反射/折射、高分辨地震折射和大地电磁测深等联合剖面探测,获得了该地区近地表至Moho面的精细速度结构、电性结构和深浅构造关系.结果表明,该地区地壳可划分为上、中、下三个组成部分.其中,上地壳厚为12~14km,波速为5.7~5.9km/s;中地壳厚度约为10km,波速为5.9~6.2km/s;下地壳厚为10~11km,波速为6.2~6.3km/s,Moho面深度约为32km.剖面浅部地质构造复杂,共解释出12条特征明显的断裂.其中,除3条断裂错断结晶基底(G界面)并向下延伸至上地壳底界面外,其他断裂均在深度3~5km以上终止或收敛于G界面之上.此外,仅在剖面西侧基底下部约13~15km埋深处发现一厚度在2km左右的壳内高导层.所以,在综合各方面资料后分析认为,在剖面经过地区不存在发生大地震的深部构造条件,近地表所存在的活动断层是未来产生对该区有影响地震的震源区.
Through the combination of deep and shallow seismic reflection, wide-angle seismic reflection / refraction in the earthquakes, high-resolution seismic refraction and telecontinental sounding in the Shanghai area, the fine velocity structure, electrical structure and The results show that the crust in this area can be divided into upper, middle and lower parts, of which the upper crust thickness is 12 ~ 14km, the velocity is 5.7 ~ 5.9km / s, the thickness of the middle crust is about 10km, the velocity of wave And the depth of Moho surface is about 32 km.The geological structure in the shallow section of the section is complex and a total of 12 faults with obvious features are explained, of which, the thickness of the lower crust is 10 ~ 11 km, the velocity of wave is 6.2 ~ 6.3 km / , Except for the three fault-broken crystalline basement (G interface) and extends down to the upper crust bottom interface, the other faults all terminate or converge on the G interface at a depth of 3 ~ 5km.In addition, About 13 ~ 15km buried depth of the discovery of a thickness of about 2km in the shell of high-conductivity layer.Therefore, after comprehensive analysis of various data that does not exist in the section through the area of deep seismic conditions, the occurrence of near-surface Active faults are the source of earthquakes that have an impact on the area in the future .