Evaluating the effectiveness of total horizontal derivative method and tilt angle of the horizontal gradient method in determining fault structure on the continental shelf and in deep water in the East Sea of Vietnam

Tran Tuan Duong1,*, Tran Tuan Dung1,2, Nguyen Ba Dai1 , Tran Trong Lap1 , Nguyen Kim Dung1 , Tran Xuan Loi1 , Bui Ngoc Quang1 , Tran Hoang Tam3

Received: 3 September 2020; Accepted: 26 November 2020

Abstract

The study of determining fault by gravity data is a popular solution in geophysical interpretation, the faults are determined through density contrast between geological structures. Total horizontal derivative method (THDR) determines the horizontal variation of gravity anomaly. This method is used to indicate geological structure boundaries based on abnormal changes in THDR values. Determining, bonding the maximum points of THDR will give us the spatial distribution of the system of faults. Tilt angle of the horizontal gradient method (TAHG) shows the geological structure in more detail and can identify the fault positions in small structures. The system of faults in both methods is determined and bonded according to the value and the maximum position of the anomaly of THDR and TAHG. In this study, we calculate and compare the results of two methods, using synthesized model to interpret gravity anomalies. The results of the paper are valuable in geological structure research, mineral exploration on continental shelf and in deep-lying East Sea of Vietnam.

Keyword: Gravity anomaly, fault, East Sea, THDR, TAHG.