5.12汶川大地震极震区灾害致因初析

 对5.12汶川大地震极震区进行的初步地震灾害地质调查结果表明：地震灾害沿断裂带呈带状密集分布，地震地表破裂带经过之处震灾最严重；地震次生地质灾害大量产生还与区内志留系茂县群千枚岩和三叠系须家河组砂岩夹页岩、煤层等软弱地层以及第四系松散层和强风化岩石等软弱岩体分布广泛、极震区大部分地区处于河谷深切、地形高差大、山体破碎的中-高山区有关。特大地震灾害再次提醒人们，在建筑场地选址中必须考虑活动断裂问题；城乡规划建设必须开展地质灾害风险评估和建筑物抗震设计；必须重视人-地关系和人-环境的关系。

Preliminary Studies on Causation of Catastrophes in Meizoseismal Areas of the 5.12 Wenchuan Huge Earthquake

Some results of primary investigations on the seismic catastrophes in the meizoseismal areas of the 5.12 Wenchuan huge earthquake are reported in this paper. The seismic disasters were concentrated along the fault zones and the most serious catastrophes occurred in the areas where ground seismic ruptures developed. The other two causes accounted for the huge geologic disasters induced by the earthquake were widespread distribution of weak rock-masses and mountain landforms. The weak rock-masses consisted of phyllites of the Silurian, named as the Maoxian Group, sandstones with weak intercalated layers of shale and coal of the Triassic, named as the Xujiahe Formation, loose deposits of the Quaternary, and as well as other strongly weathering rocks. The tremendous seismic catastrophes of the 5.12 Wenchuan earthquake reminded people that in site selection of urban rural constructions, it is necessary to consider the problems of active faults, to make a hazards evaluation of the geologic disasters and antiknock architectural design, and to pay attention to the human earth and human environment relationship.