基于重力异常连续复小波变换的断裂分析

Fracture analysis based on continuous complex wavelet transform for gravity anomalies

（1.同济大学海洋地质教育部重点实验室，上海200092； 2.西北大学大陆动力学国家重点实验室，陕西西安710069）

State Key Laboratory of Marine Geology,Tongji University,Shanghai 200092,China

阐述了连续复小波变换和系数量化编码的方法原理，并基于复杂地质模型讨论了重力异常中的断裂特征与小波系数极值特征的对应关系。小波变换系数量化编码结果表明，低尺度小波系数极值可以准确定位断裂在地表的位置；随着尺度的增加，小波系数极值会发生偏移，可以判断断裂的倾向和倾角的相对大小；小波系数极值可以反映断裂两侧地层的密度差异，为断裂分析提供物性信息。将此方法应用于塔里木盆地和天山地区的实际重力资料解释，结果不仅与实际相符，并得出中天山与南天山可能具有特殊构造模式的认识。

The principles of continuous complex wavelet transform and matrix quantitative coding were described,and the relationship between fracture features in the gravity anomaly and extreme wavelet coefficients based on integrated forward model was discussed.The results of quantitative coding to wavelet transform coefficient show that low-scale extreme wavelet coefficients can accurately localize the subaerial position of fractures.The shifting of extreme wavelet coefficients can be used to judge relative magnitude of dip angle and dip direction of fracture with scale increasing.The value of extreme wavelet coefficients can reflect density difference of formations on both sides of fracture and provide information of physical properties for fracture analysis.This method has been applied to Tarim basin-Tianshan orogenic belt to interpret the gravity data.The result coincides with the actual data,and the recognition is drawn that special structural pattern may exist in Middle and South Tianshan orogenic belt.