基于地应力实测数据分析郯庐断裂带中段滑动趋势

发布时间：2018-08-26 17:22

【摘要】：郯庐断裂带潜在滑动趋势对于区域地壳稳定性评价具有重要的意义。对郯庐断裂带中段(新沂至渤海段)附近12个钻孔共65条实测地应力数据分析,得出该区段最大和最小水平主应力与垂直应力之比K_(max)和K_(min)的范围,结果表明郯庐断裂带中段主要表现为逆断层的应力状态,局部地区呈现出有利于走滑断层的特征。研究区内应力比K值由西向东逐渐增大,并在东北部达到最大。通过计算得出断层面上的剪应力与有效正应力比值小于Byerlee准则所定义的摩擦系数,说明目前郯庐断裂带中段处于相对稳定状态;同时发现北西向断裂面上的剪应力与有效正应力比值比北东向断裂的大。区内应力积累指标μ_m的计算结果和地震的分布特征表明,郯庐断裂带中段北西向断裂上地震活动频繁,应力积累程度低;而北东向断层上应力积累程度高,特别是处于郯庐断裂带中段东北部的北东向断层,在应力集中的区域出现地震空白区,推测为断层的锁固段。最终认为在现今应力场下郯庐断裂带中段更易沿北西向的断裂滑动。
[Abstract]:The potential slip trend of the Tan-Lu fault zone is of great significance for the evaluation of regional crustal stability. The field stress data of 65 boreholes from 12 boreholes in the middle section of the Tanlu fault zone (Xinyi to Bohai) are analyzed, and the range of maximum and minimum horizontal principal and vertical stress ratios K _ (max) and K _ (min) are obtained. The results show that the middle part of the Tan-Lu fault zone is dominated by the stress state of the reverse fault, and the local area is characterized by a favorable strike slip fault. The stress ratio K increases gradually from west to east in the study area and reaches its maximum in the northeast. The ratio of shear stress to effective normal stress on fault plane is less than the friction coefficient defined by Byerlee criterion, which indicates that the middle part of Tanlu fault zone is relatively stable at present. It is also found that the ratio of shear stress to effective normal stress on NW fault plane is larger than that on NNE fault. The calculated results of stress accumulation index 渭 m and the distribution characteristics of earthquakes indicate that the upper faults in the middle section of the Tan-Lu fault zone are frequently seismically active and the degree of stress accumulation is low, while the degree of stress accumulation is high on the north-east fault. Especially in the northeast of the Tan-Lu fault zone, there is a seismic gap in the area where the stress concentration is concentrated, which is supposed to be the locking section of the fault. It is concluded that the middle part of the Tan-Lu fault zone is more prone to slip along the NW direction under the present stress field.
【作者单位】：中国地质大学(北京)工程技术学院;中国地震局地壳应力研究所地壳动力学重点实验室;
【基金】：国家自然科学基金项目(41274100,41574088) 中央级科研院所基本科研业务项目(ZDJ2012-20)
【分类号】：P315.2

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