声波方法在城市活断层探查与评价中的应用——人工地震、雷达和声波方法的比较与组合  

The Application of the Acoustic Method to the Exploration of Urban Active Fault:Comparing with the Artificial Earthquake, Radar and Acoustic Method

作　　者：赵根模[1] 王大宏[1] 任峰[1] 陈宇坤[1] 

机构地区：[1]天津市地震局,天津300201

出　　处：《中国地震》2003年第3期217-224,共8页Earthquake Research in China

基　　金：天津隐伏断裂探测与定量评价工程项目之一

摘　　要：断层上断点深度是确定平原隐伏断层活动年代的关键数据 ,对同一断层用不同物探方法获得的数据相差可达几十到几百米 ,这一差值可能导致对断层活动性的判定结论完全相反 ,由于缺乏宽频带、中心频率高的人工震源 ,只能采用多种方法联合探测。人工地震波、电磁波和声波的频率越高 ,分辨率越高 ,但衰减快 ,可探测深度也降低。相反 ,频率低 ,分辨率下降 ,但探测深度增大。人工地震波频率为数十赫兹 ,探测深度大 ,分辨能力低。雷达电磁波为 10 6HZ量级 ,分辨能力强 ,但探测深度很小。声波为数千赫兹 ,分辨能力优于人工地震 ,探测深度大于雷达 ,性状介于二者之间 ,适合厚层第四纪沉积层的超浅层探查。声波高分辨率超浅层探测的初步结果表明 ,以往华北平原东部某些断层活动性的论断可能要做很大的修正。The upper fault point depth is the key data for ascertaining active date of the plain buried fault. The difference of depth obtained from same fault may be decades to several hundred meters when using different geophysical methods. The conclusions about a fault activity would be adverse greatly and result in erroneous judgment. Because of lacking artificial earthquake source with wide band and high mid-frequency, many kinds of methods have to be used to detect jointly. The higher the frequency of the artificial earthquake wave, electromagnetic wave and sonic wave, the higher the resolution, but the attenuation is very fast and the exploration depth is very shallow. The reverse is true. The frequency of artificial seismic wave is decades Hz. Its exploration depth is big and the resolving power is small. The frequency of radar electromagnetic wave is about a million Hz, indicating that the resolving power is better, but the exploration depth is very shallow. However, the acoustic frequency is thousands of Hz, its resolving power is better than that of artificial earthquake method, the exploration depth is larger than that of radar method. So it is suitable for extra-shallow exploration in the heavy deposit strata of Quaternary. The preliminary result indicates that the previous inference about some fault activities in the eastern part of North China plain maybe needs to be corrected greatly.

关 键 词：声波 活断层 

分 类 号：P315[天文地球—地震学]