Recent tectonics, geodynamics and seismotectonics in the Ninh Thuan Nuclear Power plants and surrounding regions, South Vietnam. (January 2020)

• Record Type: Journal Article
• Authors: Nguyen-Van, Huong; Phong, Tran Van; Trinh, Phan Trong; Liem, Ngo Van; Thanh, Bui Nhi; Pham, Binh Thai; Bui, Dieu Tien; Bieu, Nguyen; Vinh, Hoang Quang; Xuyen, Nguyen Quang; Tuc, Nguyen Dang; Thom, Bui Van; Thuan, Nguyen Viet; Thao, Bui Thi; Phong, Lai Hop; Vinh, Vu Duy; Tan, Mai Thanh; Hai, Vy Quoc; Lan, Nguyen Mai; Cuong, Tran Quoc; Hang, Pham Thi Thu; Ha, Vu Van; Hoang, Cu Minh; Hao, Duong Van; Son, Tong Phuoc Hoang
• Is Part Of: Journal of Asian earth sciences. Volume 187(2020)
• Publication Date: 2020-01
• Subjects: Recent tectonics -- Capable fault -- GPS -- Horizontal displacement -- Strain rate -- Maximum Credible Earthquake; Earth sciences -- Asia -- Periodicals; Sciences de la terre -- Asie -- Périodiques; Earth sciences; Asia; Periodicals; 555.05
• DOI: 10.1016/j.jseaes.2019.104080
• Languages: English
• ISSNs: 1367-9120

Abstract

Graphical abstract: Highlights: Present-day crustal motion from GPS velocities are less than 30 mm/year to the SE. Quarternary geologic and modern geodetic strain rates show long earthquake recurrence. Present-day stress state is in strike-slip regime with NW–SE maximum principal stress. Maximum Credible Earthquake has estimated magnitude of 5.9–6.5 for Ninh Thuan Nuclear site. Abstract: We studied recent tectonics and present-day geodynamics in the Ninh Thuan nuclear power plants and surrounding regions to reveal seismogenic faults, deformation and evaluation of seismotectonics using various methods such as remote sensing, GPS, seismic interpretation, and stress and strain analysis. We based our study on geomorphological investigation, satellite images, fault gouge, drilling core, fault scarps and analysis of offshore seismic profiles to determine the capable faults in the studied region. Using international reference frame ITRF08, we determined the absolute velocities of the GPS stations with a slip rate to the east of 22.5 to 25.3 mm/year and to the south of 4.4 to 8.4 mm/year. The present strain rate was determined from present tectonic velocities that were consistent with the recent strain rates determined from topographic profiles, the slip rate of capable faults, and the thickness of Pleistocene sediments. The present strain rate variation from 10 to 30 nano per year demonstrated that the studied region has been weakly deformed under a stable tectonic regime. The state of stress determined from the fault population, focal mechanism, borehole breakouts and drilling-induced tensile fracture methods indicated that the area was deformed primarily under a strike-slip regime with a small extensive component. The maximum credible earthquake was determined from the dimensions of the capable fault and state of stress using various methods. From these capable faults, we suggest monitoring the faults, which could produce a Maximum Credible Earthquake (MCE) over a range of 5.9–6.5.