楔形鄂霍次克板块的俯冲与被俯冲及其板内洋缘盆地演化的动力学研究

项目名称： 楔形鄂霍次克板块的俯冲与被俯冲及其板内洋缘盆地演化的动力学研究

项目编号： No.41474086

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 天文学、地球科学

项目作者： 魏东平

作者单位： 中国科学院大学

项目金额： 110万元

中文摘要： 鄂霍次克板块是一个伴有数个洋缘盆地的楔形大陆板块，由远东西伯利亚、鄂霍次克海大部、整个勘察加半岛、以及萨哈林与北日本地区组成。它以走滑方式北接北美板块，南邻菲律宾海板块，东部边界受到来自西北太平洋板块的强烈俯冲，西部边界北段与欧亚板块以张性接触方式相邻，南段自萨哈林岛北端向南沿日本海东缘，接力俯冲到阿穆里亚板块下方，整个鄂霍次克板块的东西两侧边界及邻近地区，因此持续处于地震的多发与强发状态。 本研究利用逐渐累积的地质与地球物理来源的观测数据，通过构建鄂霍次克板块岩石层三维结构及力学模型，使用空间有限单元与时间有限差分方法，考虑该板块东西两侧俯冲带之大俯冲速率下的弹塑性特征，模拟鄂霍次克板内形变与应力场的时空变化以及板内不同洋缘盆地演化的差异特征，探索驱动其板块运动的各种力源及形成板内洋缘盆地的演化机理。该研究可以帮助我们加深理解发生于东北亚包括中国大陆东北地区一些地震的孕育与发生机理。

中文关键词： 鄂霍次克板块；洋缘盆地；板块运动；俯冲带；动力学模拟

英文摘要： The Okhotsk plate is a wedge-shaped continental plate including some marginal basins. It consists of far eastern Siberia, most part of the Sea of Okhotsk, the entire Kamchatka, Sakhalin Island, and the Northern Japan regions. It contacts with the North American plate and the Philippine Sea Plate along the northern and southern strike-slip boundaries, respectively, and contacts with the Eurasian plate along the northern part of the western divengent boundaries. However, the Okhotsk plate faces to strongly subducting actions from the northwestern Pacific plate along the eastern boundaries of the Okhotsk plate while it subducts to Amurian plate from northern Sakhalin, along the eastern margin of the Japan Sea, to central Japan. The southwestern and eastern boundaries of the Okhotsk plate and its surrounding areas are thus the places continuously producing a lot of earthquakes, and huge earthquakes somtimes. In this study, we take full advantage of the geological and geophysical source of observational data accumulated by these years of researches, and establish three-dimensional models describing the Okhotsk lithospheric plate and the corresponding mechanisms. By using the finite element method in spatial and finite difference method in temporal, we study how the subducting processes related to the Okhotsk plate influence the intraplate deformations and stresses, and simulate the detailed formation and evolution processes of those marginal basins in the Okhotsk plate. We take the elastoplastic features of slabs along the eastern and western boundaries into account for the large rate of subduction case. We then explore the all the possible forces driving the Okhotsk plate motion and the evolution mechanisms forming these different marginal basins. This research can also help us to understand more about the formation mechanism of some earthquakes occurring in Northeastern Asia areas including the northeast China regions.

英文关键词： Okhotsk plate;marginal basin;plate motions;subduction zone;Geodynamical simulation