Analysis of characteristics of measured stress and stability of faults in North China
Analysis of characteristics of measured stress and stability of faults in North China
复制标题
DOI：
--
复制
发表时间：
2013
影响因子：
1.5
通讯作者：
Huang Lu-yua
中科院分区：
文献类型：
--
作者：
Huang Lu-yua
华北地区的水压致裂和应力解除测量资料主要来源于“中国大陆地壳应力环境基础数据库”，共计1 017条，研究了华北地区及研究区的宏观应力场特征，结果表明：（1）最大水平应力H和最小水平应力h均随深度线性增加; (2)研究区2000 m深度的中间回归值变化较大，震级基本特征是东高西弱。(3)侧压力系数Kav =225/D+0.61随深度的变化范围为：15/D+0.42≤Kav ≤ 1030/D+0.76。Kav在地壳表层分布较分散，向深部分布较集中，并趋于0.61。(4)华北东部地区H向以近E-W、NEE-SWW和NE-SW为主，鄂尔多斯地块及其周边地区以NE-SW和NEE-SWW为主，华北平原地区以NE-SW和NNW-SSE为主，部分地区以NW-SE为主。500 m以下的应力差未达到断层活动的临界值，500 m以上的应力差已达到或超过走滑断层的滑动摩擦阈值。
The hydraulic fracturing and stress relief measurement data of North China was collected mainly from "Fundamental database of crustal stress environment in continental China".The entries of in situ stress data are 1 017.The characteristics of macroscopic stress field in North China and study regions are investigated.The results are as follows:(1) The maximum horizontal stress H and minimum horizontal stress h all increase linearly with depth.(2) The intermediate regression value of(at 2 000 m depth) is various in study regions;and the basic characteristic of magnitude is high in east and weak in west.(3) The range of the lateral pressure coefficient Kav =225/D+0.61 with depth is: 15/D+0.42≤Kav ≤1 030/D+0.76.The distribution of Kav is scattered in superficial crust,becomes more concentrated in the deeper crust and trends to 0.61.At a critical depth of 577 m Kav equals to 1 which indicates the transition from horizontal to vertical stress domination.(4) The predominant directions of H are nearly E-W,NEE-SWW and NE-SW in east regions of North China.The directions of in study regions in and around Ordos block are mainly NE-SW and NEE-SWW.In study regions of North China Plain,the H directions are dominantly shown as NE-SW;and NNW-SSE,and some directions are NW-SE.Fault stability in North China are investigated: The stress difference at depths bellow 500 m has not reached the critical value of fault activity;and stress difference at depth above 500 m has reached or exceeded the sliding friction threshold of the strike-slip fault.