【摘要】 北京通州—河北三河地区中存在几条大型隐伏断裂，地质构造复杂.为研究该区隐伏断裂的空间展布、断裂与隆起和凹陷的构造关系，本文利用布设在该区的914个短周期地震仪组成的密集台阵，获得了45天的连续波形记录，通过噪声互相关方法获得台站之间的面波经验格林函数，提取2～8 s基阶勒夫波群速度频散曲线，反演获得该区深度7.5 km以内的三维精细S波速度结构.结果表明，研究区的断裂展布影响了地质构造单元的速度异常分布，其中夏垫断裂、南苑—通州断裂和李桥断裂是高低速区的分界带，南苑—通州断裂附近的高速体大致沿NE向展布，南口—孙河断裂附近的高速体大致沿NW向展布，高速体的展布方向与断裂的走向有相关性.研究区的S波速度分布有明显的非均匀性，高速区主要分布在大兴隆起上，而在大兴隆起的中部还存在一个明显的低速体，大厂凹陷和俸伯凹陷主要表现为低速特征，断裂两侧的较大地层密度横向差异可能是地质构造单元呈现出高低速异常的原因之一.研究区的结晶基底埋深差异较大，大兴隆起的结晶基底埋深约为2 km,大厂凹陷的结晶基底埋深约为4～7 km,断裂影响了结晶基底的埋深状态.本文获得的通州—三河地区三维精细S波速度结构，为认识该区的隐伏断裂、隐伏隆起和凹陷的物性结构提供了更多的地球物理学依据，对城市的地质灾害风险评估、安全建设等有重要意义.更多还原

【Abstract】 There are several large buried faults in Tongzhou-Sanhe area of Beijing and Hebei. Geological structure in this area is complex. In order to investigate the geometry of buried faults and tectonic relationship between the faults and buried uplifts and depressions, we use the ambient noise data from dense array which is consist of 914 short-period temporary seismic stations. We use the 45 days′ continuous waveform records to calculate the noise cross-correlation functions. Then, we measure dispersion curves of fundamental-mode Love waves in the periods of 2～8 s by empirical Green′s function of the station pairs. We finally invert the fine 3 D S-wave velocity structure within 7.5 km in study area. The results show that the distribution of faults in study area has affected the velocity anomaly′s distribution of geological tectonic units. The Xiadian fault, Nanyuan-Tongxian fault and Liqiao fault are the boundary belts between high and low velocity zone. The high-speed anomalies near Nanyuan-Tongxian fault are mainly distributed in the direction of NE. The high-speed anomalies near Nankou-Sunhe fault are mainly distributed in the direction of NW. The distribution of S-wave velocity in study area has obvious heterogeneity. High velocity zone mainly located in Daxing uplift. However, there has a low velocity zone in the middle of the Daxing uplift. The Dachang and Fengbo depression mainly show obvious low velocity anomalies. The obvious lateral difference in the formation density on both sides of the fault may be one of the reasons why the geological tectonic units exhibit high and low speeds anomalies. The depth of crystalline basement in study area has obvious difference. The depth of the crystalline basement in Daxing uplift is about 2 km and that in Dachang depression is about 4～7 km. Faults have affected the depth of the crystalline basement in study area. The 3 D fine S-wave velocity structure in Tongzhou-Sanhe area obtained in this paper provides more geophysical basis for understanding the deep physical structure of the buried faults, uplifts and depressions. The results have great significance to the geological disaster risk assessment and safety construction in urban city.更多还原