南海北部陆缘反“S”型构造带及其对地震活动的影响

通过地形—地貌、断裂构造、地壳结构、中新生代沉积盆地、第四纪地质特征等分析,认为南海北部陆缘存在滨岸岛链、陆坡北缘和陆坡南缘三条反“S”型构造带,它们形成于晚第三纪,较“新华夏系”和“南海系”晚。上新世末期以来,反“S”型构造带的活动方式,对南海北部陆缘第四纪地质特征影响显著,同时控制了这一区域的地震活动方式和地震带展布,其中,“滨海地震带”和“雷琼地震带”同属于滨岸岛链带,“台西滨外地震带”和“东沙—海南地震带”同属于陆坡北缘带。

THE PROPOSAL OF REVERSE "S" STRUCTURE ZONES ALONG THE NORTHERN CONTINENTAL MARGIN OF SOUTH CHINA SEA AND THE PRELIMINARY REALIZATION OF ITS INFLUENCE ON EARTHQUAKE ACTIVITY

By analysis of landform, fault system,crustal construction,Mesozoic-Cenozoic basin,Quaternary geology and so on, it is suggested that there are three reverse"S"structure zones, namely, South China Littoral - Island Zone, North Margin Zone and South Margin Zone of continental slope, along the northern continental margin of South China Sea. They are formed in Late Tertiary, "Neocathaysian" and "South China Sea System". Since the end of pliocene, the active state of reverse "S" structure zones has played obvious actions on the characteristic of Quaternary geology, and it also controls the active ways of earthquakes and the distribution of earthquake belts in the studing region. Among them, South China Littoral Belt and Leiqiong Belt belong to South China Littoral - Island Zone, Taixi -Littoral Belt and Dongsha - Hainan Belt belong to North Margin Zone of continental slope.