Abstract:Using wavelet analysis method to process aeromagnetic data in the Qinghai-Tibet plateau, aeromagnetic anomaly maps with different scales are obtained. Results from the first order wavelet analysis reveals the structure feature of shallow crust. In the sutureⅠ and sutureⅡ regions, there exist several clear arcuate structures with NWW-striking, as shown by alternatively positive and negative magnetic anomaly belts. There exists a negative magnetic anomaly belt with near EW-striking in suture Ⅳ near Golmud. The results from the third order wavelet analysis show the structure feature of deep crust. The main feature of deep structure in this region is represented by an obvious negative magnetic anomaly belt with near NS-striking between 87°N and 93°N. The Nepal M8.1 earthquake and its three strong aftershocks with magnitude 7 all occurred near the southern end of this magnetic anomaly belt, where the EW strike Himalaya tectonic belt intersects with the NS-striking negative magnetic anomaly belt. In general, the aeromagnetic data in Qinghai-Tibet plateau shows that, the main feature of shallow structures is near EW-striking, but the deeper structure is SN-striking. It implies that the intersection of the complex overpass structures is the tectonic background of the Nepal M8.1 earthquake.
LAI Xiaoling,SUN Yi. Analysis to Tectonic Background of M8.1 Nepal Earthquake Using Aeromagnetic Data in Qinghai-Tibet Plateau[J]. jgg, 2016, 36(7): 595-599.