青藏高原及周边2001年以来三次特大地震引起的形变场分布特征

基于地壳黏弹模型在GPS观测资料和地震位错数据为约束条件下，应用有限元数值模拟方法对2001年昆仑山8.1级、2008年汶川8.0级和2015年尼泊尔8.1级特大地震引起的地壳形变分布特征进行了模拟计算，获得了地震位移场和形变场.这3次大地震分别发生在青藏高原的北部、东部边界和南部边界，尽管震级大小基本相当，但发震区域和发震断层性质都各不相同，其各自产生的地壳形变场分布特征存在明显的差异，主要表现为形变场区域大小、幅值大小等的差异，以及在不同地壳深度也存在明显的差异，这些差异主要取决于地震断层性质和地下介质结构的不同.通过模拟计算，可以进一步了解大地震产生的应力加卸载区分布特征，对预测未来地震发生区域范围提供重要参考依据.

The distribution characteristics of deformation field caused by three great earthquakes in the Qinghai-Tibet Plateau and its vicinity since 2001

Based on a viscous-elastic crustal model with constraint conditions from GPS and seismic dislocation data and adopting the finite element method, we analyzed the crustal deformation characteristics caused by 2001 Kunlun Mountain M_S8.1, 2008 Wenchuan M_S8.0 and 2015 Nepal M_S8.1 earthquakes, obtained the displacement and deformation field. These earthquakes have occurred in the north, east, and south margins of the Tibetan Plateau respectively. Our primary results suggest obvious differences in deformation regimes, seismogenic fault geometry and source parameters, as well as crustal deformation patters despite the substantially similar magnitudes. These differences caused by seismogenic fault nature and subsurface structures are mainly manifested by different scopes of deformed regions and different strain amplitudes. Through these simulation results, we can detect more about the distribution characteristics of stress loading and unloading area caused by large earthquakes. Moreover, it plays an important role in forecasting the earthquake possibility of seismogenic region.