MULTI-SCALE DECOMPOSITION OF BOUGUER GRAVITY ANOMALY AND SEISMIC ACTIVITY IN NORTH CHINA

摘要

Bouguer gravity anomaly in North China is decomposed with multi-scale decomposition technique of wavelet transform. Gravity anomalies produced by anomalous density bodies of various scales are revealed from surface to Moho. Characteristics of anomalies of different orders and corresponding structural features are discussed. The result shows that details of wavelet transform of different orders reflect the distribution features of rock density at different depths and in various scales. In most cases, the two sides of a fault-especially a deep and large fault-in North China differ greatly in rock density. This difference records the history of the formation and evolution of the crust. Deep structural setting for the Ms≥7.0 strong earthquakes in this region is also discussed.