Phân tích dữ liệu từ vùng vĩ độ thấp sử dụng phép biến đổi wavelet liên tục hai chiều

Abstract

Nowadays, the continuous wavelet transform has been applying for interpretation of potential field data to detect accurately the location for the anomaly sources and their properties. For magnetic data at low latitude areas such as the Mekong Delta (latitudes 11,07o), both of the magnetization and ambient field are not directed vertically, making magnetic anomalies antisymmetrical and often skewed to the location of the sources. So it is significantly problematic to interpret these anomalies. In this paper, two-dimensional continuous wavelet transform (2-D CWT), using Farshad-Sailhac complex wavelet function is studied and applied for reducing the magnetic anomaly to a symmetrical one - this located on the source of the anomaly, and then determining the position of the center of the object causing anomalies by wavelet transform modulus maxima (WTMM) method, to enhance the quality of magnetic data interpretation in this area. Furthermore, to determine the anomaly sources ’s properties effectively, the relationship between the source depth and the scale corresponding the maximum point of the wavelet transform coefficients as well as the equation for estimation the one size have been formed. After verifying the reliability of the proposed method on the modeling data, a process for the location of the magnetic anomalies at low latitude areas using the wavelet transform is set up, and then application for analyzing the magnetic data in the Mekong Delta.