Using the analytic signal method of gravity gradient tensor (GGT) to determine the location and depth of the faults in the Pre-Cenozoic basement rocks of the Red River trough

Nguyen Kim Dung^*1, Do Duc Thanh²

¹ Institute of Marine Geology and Geophysics, Vietnam Academy of

 Science and Technology

² Hanoi University of Science, Vietnam National University

Received 12 August 2015. Accepted 13 April 2016

ABSTRACT

    In this paper, we present the study results of using the directional analytic signal method of gravity gradient tensor (GGT) and the Euler deconvolution of the directional analytic signals to determine location and estimate the depth of fault systems in the Pre-Cenozoic basement in order to improve the efficiency of Pre-Cenozoic basement structure. The method is tested on the 3D digital model, which shows that not only the location and depth of resources are determined but also can overcome undue interference, which could be met in the previous analytic signal methods. To study more about the applicability of the method, we applied the method for the gravity anomaly data of Red River Trough. Obtained preliminary results have shown the location of major faults in the region: Song Lo fault, Song Chay fault, Red River fault, etc. and initially (in the first time), by this method, the depth of over 10 km the fault persists. This depth is deeper than the depth of the surface of Cenozoic boundary determined by other methods, proves that the faults appear in the Pre-Cenozoic basement.

    Keywords: Gravity gradient tensor; Euler deconvolution; fault; analytic signal