[关键词]
[摘要]
滇西南普洱一带地质构造复杂,中-强地震成群活动特征明显,地壳的形变特征与形变机制引起了地学界的广泛关注和深入研究。在参考、借鉴以往研究成果的基础上,本文构建了普洱一带包含活动断裂的二维板有限元模型,以GPS测量得到的块体年运动量作为模型区域的边界约束,模拟计算获得了普洱地区的构造形变空间分布,以NEE、NNW 2个方向、从数值模拟角度对普洱地区的水平形变特征和区域地壳垂直形变场进行了分析和探讨。结果表明:在青藏高原东南缘扩展、高原物质重力滑塌型南东向移动的动力学背景下,研究区内NEE向断裂的活动带动牵引NNW向断裂共轭运动,隆升性质的垂直形变场与60年的大区域水准测量结果相吻合,沿NNW向形变场的分布无规律,应是区域应力累积和震后调整双重作用的结果。沿NEE向形变场呈现了较明显的西部大于东部的分布图像,特别是西北部高值区对应了2014年景谷6.6级强震,最后对研究区的区域动力学问题进行了初步探讨。
[Key word]
[Abstract]
There is the special structure combination and the concentration of strong earthquake in the Pu'er block. The geology phenomena of motion and deformation caused by motion of the active fault and the sub-block which brings the extensive attention and further research to the scholar of geological society. Basing on the past research achievements,we will construct the 2 dimensional shell finite element model of Pu'er region containing the active fault. Applying the velocity of block per year measured by GPS data and the researches on the geology and geomorphology as the boundary conditions of finite element model,we then compute the spatial distribution of deformation in the Pu'er region and simulate the deformation displacement along the NEE and NNW direction. Lastly,we analyze the characteristics of horizontal and vertical displacement field in the Pu'er region. The numerical result shows that extension motion of the southeastern margin of the Qinghai-Tibetan Plateau makes the movement of slump due to the gravity. In the research area,the motion of fault with NEE strike draws the fault with the NNW strike to move in conjugation direction. The vertical deformation caused by the uplift movement is agreed with the result of 60 years of larger regional leveling and the deformation along the NNW direction is distributed irregularly which is made possible by the regional stress accumulation and adjustment after the earthquake. The deformation field along the NEE direction is larger in western part of Pu'er region than that in eastern part,especially the northwest part of region which is corresponding to the recent Jinggu MS6.6 earthquake. Lastly,we analysis preliminarily the dynamic problems in research area.
[中图分类号]
P315
[基金项目]
国家自然科学基金(41374026)资助