湖北地区现今GPS形变特征研究

选取中国地壳运动监测网络1998～2018年GPS观测数据，基于插值法计算湖北地区的形变和应变特征。初步研究结果表明，湖北地区地块运动稳定，无明显的形变梯度带，水平运动方向为东向微偏南，速率为5～9 mm/a，平均值为6.2 mm/a；垂直速度场平均值为-0.96 mm/a，以下降运动为主。面膨胀率结果显示，湖北地区具有4个面膨胀高值区和4个面挤压高值区。最大剪应变率场显示，在湖北中部地区形成一个高值环形带，湖北历史地震主要发生在应力应变高值区边缘带。巴东和秭归小震频发与长江三峡水库水位反复加卸载有关，GPS形变和应变无明显对应特征。

Study on Present GPS Deformation Characteristics of Hubei Province

We calculate the deformation and strain characteristics of Hubei province by interpolation method based on 1998 to 2018 GPS observation data of the crustal motion observation network in China. The results reveal that the movement of the block in Hubei province is stable and without obvious deformation gradient zones. The direction of horizontal movement is east to slightly south, the speed value is between 5 mm/a and 9 mm/a with 6.2 mm/a average. The average of vertical velocity field is -0.96 mm/a, mainly sinking. The superficial expansivity shows that there are 4 high value zones of surface expansion and 4 high value zones of surface extrusion in Hubei province. The maximum shear strain rate field shows there is a high value annular zone in middle Hubei province. The distribution of historical earthquakes in Hubei province shows that earthquakes mainly occur in the edge zone of high-value stress and strain area. Small earthquakes often occur in Badong and Zigui regions, which have a certain relationship with the repeated loading and unloading of water level in the Three Gorges reservoir, and it has no obvious feature which correspond to GPS deformation and strain characteristics.