Bằng tổ hợp các phương pháp phân tích ảnh viễn thám, địa chất, địa mạo, địa chất thủy văn, địa vật lý, từ các số liệu lỗ khoan địa chất công trình, bước đầu đã làm sáng tỏ đặc trưng cấu trúc kiến tạo, nguyên nhân, cơ chế của tai biến sụt đất trong khu Bằng Lũng, Chợ Đồn, Bắc Kạn. | VNU Journal of Science Earth and Environmental Sciences Vol. 37 No. 2 2021 84-97 Original Article Tectonic Structure and Relationship with Sinkhole Harzard in Bang Lung Area Cho Don District Bac Kan Province Thom Bui Van Quoc Cuong Tran Phong Lai Hop Trung Hieu Tran Duc Anh Nguyen Institute of Geological Sciences Viet Nam Academy of Science and Technology VAST Alley 84 Chua Lang Dong Da Hanoi Vietnam Received 26 April 2020 Revised 21 November 2020 Accepted 01 December 2020 Abstract By integration of remote sensing images analysis geology geomorphology hydrogeology geophysical method and drilling data the paper illustrates the structure tectonics causes and initial mechanism of a sinkhole forming in Bang Lung Cho Don Bac Kan province. The NE-SW normal slip faults are an essential fault system in the area which created Bang Lung graben valley. This fault system also forms large fracture zones creating advantage conditions for the groundwater runoff both vertically and horizontally to eroded and dissolved carbonate rock- forming underground karst caves. These are favorable natural conditions for forming a sinkhole. The sinkhole hazard in the Bang Lung area is initiated by some main factors such as tectonic activity thickness and characteristics of unconsolidated sediment layers groundwater fluctuation karst caves and human activities. The most human impacts are mining exploitation and agricultural cultivation that promote sinkholes occurring faster and earlier. The horizontal and vertical movement of groundwater dragged the material on the ceiling karst caves into ground spaces. Thereby weakening the cohesion of the unconsolidated sediment above caves leads to gravitational unbalance and creates a sinkhole. This study has also shown potential sinkhole areas in Bang Lung which helps the authorities and local people in sinkhole prevention and mitigation mission. Keywords Sinkhole karst caves tectonic Cho Don mine Bac Kan. _ Correspondingauthor. E-mail address .
