【摘要】 为了探明南海北部海陆过渡带的深部地壳结构,我们在香港外海域进行了一次海陆地震联测的实验,利用固定地震台网远距离接收海上气枪信号,接收距离远达200多km,并利用此次实验的测线1剖面模拟得到了海陆过渡带的深部地壳速度结构.速度结构模型表明:研究区海陆过渡带的地壳结构非均匀性较明显,由陆至海沉积层有一个突然增厚的特点;莫霍面深度约为26~29 km,上地壳P波速度约为5.5~6.4 km/s,下地壳P波速度为6.5~6.9 km/s.在担杆列岛往海方向有一个低速破碎带,其上地壳P波速度为5.2~6.1 km/s,下地壳P波速度为6.2~6.4 km/s,结合野外地质调查的结果,推测它可能为滨海断裂带.在担杆列岛往陆方向香港和深圳之间的研究区域,莫霍面有较大起伏,可能与此处发育的海丰断裂有关.更多还原

【Abstract】 In order to investigate the deep crustal structure across the transition zone between land and sea of northern South China Sea,an onshore-offshore deep seismic experiment was carried out offshore Hong Kong.The permanent seismic stations of Guangdong and Hong Kong region were used to record the air-gun signals for the first time.We could identify different seismic phases and clear signals from more than 200 km distance.The deep crustal structure was studied along Profile 1.The results show that the crustal structure has strong heterogeneous characteristics.The sediments become thicker seaward.The Moho depth is about 26～29 km.The P-wave velocity is about 5.6～6.4 km/s in the upper crust,and about 6.5～6.9 km/s in the lower crust.There is a low velocity zone seaward of DanGan Islands,where the P-wave velocity is about 5.3～6.2 km/s in the upper crust and about 6.3～6.7 km/s in the lower crust.it may be the Binhai(littoral) fault zone according to former studies.The depth of Moho discontinuity change a little larger landward of DanGan Islands,it maybe relate with HaiFeng fault zone.更多还原