渤海湾区域应变应力场演化特征

根据渤海湾区域1999~2013年多期GPS站点速率资料，以营潍断裂带为界分为东西两个地块计算运动参数，求解主应变率和断裂带的应变率。基于应变率计算结果研究了区域应变-应力场。结果表明，1999~2011年渤海湾区域地壳整体受北东东-南西西向压应力和北北西-南南东向张应力作用，2011~2013年区域地壳压应力主方向为近南北向，张应力主方向呈近东西向，致使这一变化的主要原因是2011年日本3.11大地震。渤海湾区域不同地段的应力也存在差异，局部性变化明显。营潍断裂带不同时段的正应变率和剪应变率亦不同，1999~2011年为右旋剪应变-剪应力作用，2011~2013年为左旋剪应变-剪应力作用。

Strain-Stress Field Evolution Characteristics in Bohai Bay Area

Using Bohai Bay region GPS rate data from 1999 to 2013, Ying-Wei fault zone is divided into two blocks, and we calculate the principal strain rate and the strain rate on the fault zone. The regional strain-stress field calculation results are studied. Results show that the 1999-2011 Bohai Bay regional crust as a whole presents NEE-SWW compressive stress and NNW-SSE tensile stress effect. For 2011-2013, the regional crust presents a N-S direction, tensile stress is nearly in an E-W direction. The main cause of the change is the Japan 3.11 earthquake in 2011. Bohai Bay area is different in localized changes obviously. The Ying-Wei fault zone presents normal strain and the shear strain rates are also different at different times; in 1999-2011 it presents dextral shear strain-shear stress, whereas in 2011-2013 it shows sinistral shear strain-shear stress.