利用重力异常反演马里亚纳海沟海底地形  

Inversion of Mariana Trench Seabed Terrain Using Gravity Anomalies

作　　者：范雕 李姗姗[1] 孟书宇 邢志斌[1] 冯进凯 Fan Diao;Li Shanshan;Meng Shuyu;Xing Zhibin;Feng Jinkai(Institute of Geospatial Information,Information Engineering University,Zhengzhou 450001,China;Xi’an Aerors Data Technology Co.Ltd,Xi’an 710054,China)

机构地区：[1]信息工程大学地理空间信息学院,郑州450001 [2]西安航天天绘数据技术有限公司,西安710054

出　　处：《吉林大学学报（地球科学版）》2018年第5期1483-1492,共10页Journal of Jilin University：Earth Science Edition

基　　金：国家自然科学基金项目(41274029;41404020;41774018;41504018);地理信息工程国家重点实验室开放基金项目(SKLGIE2016-M-3-2);信息工程大学校立课题(2017503902;2016601002)~~

摘　　要：针对利用船舶测量海底地形效率低和成本高的缺点,选取西太平洋板块俯冲菲律宾板块而形成的马里亚纳海沟所在海域作为实验区域,依据重力地质方法(GGM),利用重力异常数据反演海底地形。采用移去恢复技术确定了重力地质法模型的密度差异常数为2.32g/cm3。分析比较了GGM海深模型、ETOPO1模型和直接将船测点海深数据格网化(模型1)3种海深模型之间的差异,并依据反演结果对"挑战者深渊"两侧地貌进行了研究。结果表明:GGM模型反演海底地形的结果优于ETOPO1模型,更优于将船测点海深数据直接格网化的结果;模型相对误差与海深的关系不大,受海底地形变化影响明显;在船测数据匮乏或者过于稀疏的海域,模型间海深差值结果较大;"挑战者深渊"海沟两侧的地貌有明显差异,在海沟南侧水深小于5 000m的浅海部分,坡度平缓(2°～5°),而在水深大于5 000m的部分,坡度明显增大(10°～15°);海沟北侧在整个下降阶段坡度很大(10°～15°),11°45′N附近出现一个缓冲地带。In order to overcome the shortcomings of using ships to measure sea-depth with low efficiency and high cost,the authors selected the Mariana Trench area formed by the Western Pacific plate dive to the Philippine plate as the experimental area,and used gravity anomalies data to inverse the sea-depth according to the gravity-geologic method.The density difference constant of the GGM(gravity-geologic method)model was determined to be by using the remove-restore technique.The differences between the GGM sea depth model,the ETOPO1 model and the model 1 which directly gridded dispersed ship data were analyzed and compared,and the landforms of the“challenger abyss”trench were studied based on the inversion results.The result shows that the seafloor topography computed by GGM model is superior to that by the ETOPO1 model,and even better than the results of the directly gridding of the ship survey data.The relative error of the model is not related to sea depth,but affected obviously by the change of seafloor topography.The sea-depth differences between the models are large in the area where the ship data are missing or too sparse.The landforms on the both sides of the“challenger abyss”trench are different.In the south side,when the water depth is less than 5 000 m,the gentle slope is about 2°5°;while the water depth is greater than 5 000 m,the slope is increased significantly to about 10°15°.In the north side,the slope is about 10°15°.There is a buffer zone near latitude.

关 键 词：重力地质法 密度差异常数 向下延拓 移去恢复 马里亚纳海沟 

分 类 号：P631.1[天文地球—地质矿产勘探]