A Test of the Existence of the Eurasian - North American Plate Boundary on Sakhalin Island

北美是最大的岩石圈板块之一，在东亚的大片地区，人们对它的形态和运动知之甚少，因为北美板块的楔形末端夹在两个更大的板块--欧亚板块和太平洋板块之间。该项目的主要目标是确定北美和欧亚板块是否在库页岛汇合，形成1000公里长的板块边界。这项研究依赖于1999至2006年间在库页岛进行的GPS调查。通过这些调查的数据，可以根据地震周期不同阶段的粘弹性地壳变形来调查岛上的应变累积，从而在理解不发生俯冲的会聚板块边界的动力学方面向前迈出了重要的一步。在地震周期的不同阶段模拟了库页岛的应变累积，以确定速度场是否与欧亚-北美的相对运动相一致。正在利用GPS水平速度矢量、地震滑动矢量和南千岛弧内相对板块运动方向之间的差异来测试南千岛弧是否如北美板块下方的太平洋板块所预测的那样运动，或者是否有单独的南千岛银条。对库页岛进行观测的好处是，太平洋板块俯冲对该岛的影响很小，可以可靠地解释。另一个优点是，1995年5月27日库页岛北部发生7.0级地震后，库页岛的断层系统已经用地质方法仔细绘制了图。揭示和探索北美等主要板块与东亚相邻板块相互作用的几何学、运动学和动力学是固体地球科学中的一个重要问题。这个问题已经争论了几十年，但没有太大进展。该项目旨在了解与人口最稠密的国家之一日本毗邻的地区的构造。库页岛最近发展成为东亚石油和天然气的主要供应国。石油和液化天然气管道沿着主要的萨哈林断裂延伸，该断裂是地震活动的地方。历史上和最近，库页岛上曾发生过造成数千人死亡的灾难性大地震。该项目将有助于了解世界这一地区的地震危害。

The configuration and motion of one of the largest lithospheric plates, North American, is very poorly understood in the large region of eastern Asia, where a wedge-like extremity of the North American plate is jammed between two larger plates, the Eurasian and Pacific plates. The main goal of this project is to determine if the North American and Eurasian plates converge on Sakhalin Island making 1000-km long plate boundary. The research relies on GPS surveys performed on Sakhalin between 1999 and 2006. Data from these surveys allow investigation of the strain accumulation on the island in terms of the viscoelastic crustal deformation at different stages of the earthquake cycle and, hence, to make a significant step forward in understanding the dynamics of the convergent plate boundary where subduction does not occur. The strain accumulation on Sakhalin Island is modeled at different stages of the earthquake cycle in order to determine if the velocity field is compatible with the Eurasia-North America relative motion or not. Discrepancies between GPS horizontal velocity vectors, earthquake slip vectors, and directions of relative plate motions in the southern Kuril Arc are being use in order to test whether the southern Kuril arc moves as predicted by the underthrusting of the Pacific plate beneath the North American plate or if there is a separate south Kuril sliver. The advantage of observations on Sakhalin is that the effect of the Pacific plate subduction on this island is small and can be reliably accounted for. Another advantage is that the system of faults on Sakhalin has been carefully mapped by geologic methods following the disastrous magnitude 7.0 (Mw) May 27, 1995 earthquake on northern Sakhalin.Unraveling and exploring the geometry, kinematics, and dynamics of interaction of such major plate as North America with adjacent plates in east Asia is an important problem in solid earth sciences. This problem has been debated for decades without much progress. This project is aimed at understanding the tectonics of the region neighboring one of the most densely populated countries, Japan. Sakhalin recently developed into the major supplier of oil and natural gas for eastern Asia. The oil and liquid natural gas pipelines run along the main Sakhalin fault, which is active seismically. Large disastrous earthquakes that killed thousands of people occurred on Sakhalin in the history and quite recently. This project will contribute to understanding the earthquake hazards in this part of the world.