Chen Gui-hua

Discussion of rupture mechanisms on the seismogenic fault of the 2008 M s 8.0 Wenchuan earthquake

The May 12, 2008, Ms8.0 Wenchuan earthquake was the outcome of a recent movement of an active intra-continental thrust fault zone. The seismogenic fault of this earthquake underwent oblique-slip faulting along the central fault and pure thrust faulting along the range-front fault of the Longmenshan fault zone. The former had a steep dip and large vertical displacement, and the latter had a gentle dip and little vertical displacement. The fault zone consisted of compressive double fault ramps rupturing with right-lateral strike-slip components resulting from strain partitioning of a deep oblique slip fault in the brittle zone of the upper crust. The kinematic pattern and rupture mechanisms are complex for the seismogenic fault, as indicated by the geometric pattern of its surface ruptures, the coseismic displacement distribution and focal mechanisms of the main shock and aftershocks. As a tear fault, the NW-trending, left-lateral, strike-slip Xiaoyudong fault zone has accommodated NE-trending displacements with different shortening amounts. However, because of intense compression on the southwestern segment of the seismogenic fault, the left-lateral, strike-slip Xiaoyudong fault also carries a clear compression component. Normal faulting with a strike-slip component controls the formation of a fault-trough along the central fault, which is characterized by thrusting with a strike-slip component and strike-slip with thrusting. The fault-troughs are the product of the interaction of slip and gravity on the seismogenic fault under specific geological and geomorphic conditions. Gravitational force exaggerated the vertical component of fault displacement, which by no means represents the actual maximum vertical displacement of the seismogenic fault.

Late Quaternary Slip-rates and Slip Partitioning on the Southeastern Xianshuihe Fault System, Eastern Tibetan Plateau

在 Qinghai 西藏的高原附近散布的活跃差错的 kinematics 的定量分析是批评的理解高原的当前的构造过程。按年代先后的分析基于在地区性的气候和地形学之中的比较，数字摄影测量学，偏移量地形，和 tectonics 在东方西藏的高原在 Xianshuihe 差错上在这研究被采用。二或更多的偏移量年龄数据为 Xianshuihe 和 Yunongxi 差错的每个片断被获得。包括河梯田，冲积扇子和冰川的冰碛，偏移量地形提供限制为晚第四级滑动 Xianshuihe 差错的率。左侧面的罢工在东南片断上在西北片断上从 17 mm/a 滑动 Xianshuihe 差错减少的率到 9.3 mm/a。认为 Xianshuihe 差错地区和它的邻近的块是一个地区性的构造系统，向量分析习惯于份量上分析纵的 kinematical 转变并且横过滑倒在地区以内以主要差错的 kinematical 参数在差错地区上划分。有的结果表演一分布式垂直以越过 Gongga 山区域弄短引起的 6.1 公里 / 年的率高举。把结果基于这些，我们建立了为 Xianshuihe 差错地区的东南的片断划分的 slip 的一个模型。

3-D physical model in strong ground motion numerical simulation: A case study of Kunming basin

Seismic hazard assessment based on urban active faults can provide scientific bases for city planning and project construction, while numerical simulation of strong ground motion is an important method for seismic hazard prediction and assessment. A 3-D physical model in conformity with real strata configuration of (mainly) the Quaternary is a prerequisite to ensure the reliability of the simulation results. In this paper, we give a detailed account of the technical scheme and process for creating a 3-D physical model in Kunming basin. The data used are synthesized from seismogeological data, borehole data, topographic data, digital elevation mode (DEM) data, seismic exploration results and wave velocity measurements. Stratigraphic division is based mainly on shear wave velocity, with strata sequence taken into consideration. The model construction is finally accomplished with ArcGIS and many relevant programming techniques via layer-by-layer stacking (in depth direction) of the adjacent medium interfaces (meshes). Meanwhile, a database of 3-D physical models is set up, which provides model data and parameters for strong ground motion simulation. Some processing methods and significant issues are also addressed in the paper in accordance with different types of exploration and experimental data.