舟山海域海洋灾害地质因素分类及其分布规律  

Classification and Distribution of Marine Geohazards Factors in Zhoushan Islands

作　　者：刘杜娟[1] 胡涛骏[1] 黄潘阳[1] 季有俊[1] 

机构地区：[1]国家海洋局第二海洋研究所工程海洋学重点实验室,浙江杭州310012

出　　处：《海洋湖沼通报》2014年第3期153-160,共8页Transactions of Oceanology and Limnology

基　　金：国家海洋局第二海洋研究所基本科研业务费专项资金项目(JG0906;JG1307)资助

摘　　要：舟山海域海洋灾害地质因素可划分为两大类9种类型,两大类为活动性灾害地质因素和限制性地质条件,9种类型分别包括海底活动断层、滑坡、浅层气、潮流沙脊和沙波、海岸侵蚀(属活动性灾害地质因素)和不规则起伏的浅埋藏基岩、埋藏古河道、水下陡坎、冲刷沟槽(属限制性地质条件)等。滑坡主要是由重力作用所致,多发生在通道深槽边坡、通道凹岸、通道交汇处、通道中高地边缘、通道边坡次级沟槽等部位。浅层气主要分布在自岸滩至25m水深范围内的泥质、砂质沉积区。侵蚀海岸大多分布在濒临开敞海域的基岩海岸和岛屿向海侧。潮流沙脊和沙波多见于潮流通道的口门或口外,深槽边坡也有分布。不规则浅埋藏基岩常出现在沿岸区域和岛屿附近。埋藏古河道主要分布在舟山群岛东部海域的内陆架地区,此外,在岱衢洋、舟山岛与岱山岛之间的灰鳖洋、中街山列岛东部海域也见到少量的埋藏古河道。陡坎以侵蚀成因及滑坡成因为主,发育广泛,其高度和坡度变化较大。冲刷沟槽主要分布在岛屿之间狭窄、潮流或水流较急的区域,陡峭的沟槽常伴生陡坎,易产生滑坡,部分地段有波状微地貌发育。本文认为,研究区海洋灾害地质因素的发育离不开地形地貌、底质和水动力条件,其分布具有一定的规律性。常见多种灾害地质因素相互依存,互相触发。潮流作用下海底浅部沉积物的活动性是引起研究区海洋工程设施安全隐患的主要因素。The marine geohazards factors of Zhoushan Islands can be divided into two categories namely active and restrictive ones.There are 5 types of active geohazards factors in this area such as submarine active faults,slides,shallow gases,tidal sand ridges and waves,coastal erosions,etc.,while shallow buried rocks,buried palaeochannels,underwater scarps and tidal channels are restrictive factors.Caused by gravity,slides always are distributed in deep troughs of the channels,concave banks,conjoining of the channels and margins of relict salient in channels.Shallow gases appear in soil or sand area from beach to 25 meter water depth.Coastal erosions are mostly distributed in the brink of open sea Bedrock Coast and islands to the sea side.Tidal sand ridges and waves are found in the tidal channel mouths mainly and Irregular shallow buried rocks often appear near coastal areas and Islands.Buried palaeochannels are mainly distributed in the inner shelf area of the east Zhoushan islands.In addition,there are a small amount of buried palaeochannels in Dai Qu Yang,grey turtle ocean among Zhoushan island and Daishan Island,and east waters of Zhongjieshan islands.Underwater scarps and tidal channels developed widely in Zhoushan islands.These geohazards factors would not develop without special topography,geomorphology,sediments,and hydrodynamic conditions.These factors are distributed regularly and interdependent and trigger mutually.The activity of the shallow seabed sediments under actions of tidal current is the main factor that causes potential safety hazards for marine engineering facilities in this area.

关 键 词：舟山海域 海洋灾害地质因素 分布规律 

分 类 号：P736.5[天文地球—海洋地质]