SUMMARY

Activity characteristics of the Red River fault zone

Nguyễn Đăng Túc

The Red River shear zone extends more than 1560 km from Vexi, Yunnan (China) to Bắc Bộ Gulf (Việt Nam), seperated into 5 sections (Vexi-Midu, Midu-Dali, Dali-Manpan, Manpan-Việt Trì, Việt Trì - Bắc Bộ Gulf and Bắc Bộ Gulf) by the complex of geormophologic and structural characteristics of microfaults.

The Red River fault zone consits of the main fault and many secondary faults of  NW-SE and N-S trends. In the Vietnam’s territory, this zone is separated into the Red River and the Chảy River fault zones. They form the boundaries of the Dãy Núi Con Voi high-grade metamorphic band. The main fault have the NW-SE trend, dipping northeastward with the dip of ~ 80⁰.

The tectonic stress field in Pliocene - Quaternary has the submeridian compressive stress axis, subparallel extension stress axis and subvertical middle stress axis. The Red River fault zone is still active in the present time with the right - lateral slip. It causes many geological hazards, such as: land cracking, land and rock slide, mud flood, river-bank erosion, and forms mineral and thermal water springs, and anomalies of Rn, Hg, geotherm in many places.

Ngày nhận bài: 30-7-2004

Người biên tập: Trần Văn Trị