Kim, Sang-Wook Kim, Se-Yun Nam, Sangwook 2024-01-20T19:31:24Z 2024-01-20T19:31:24Z 2021-09-02 2010-05 0016-8033 https://pubs.kist.re.kr/handle/201004/131508 The relatively fast propagation of electromagnetic signals through empty man-made tunnels has played a key role in detecting deep underground tunnels using a short-pulse cross-borehole radar system. Our cross-borehole radar system measured the pulse signatures of an obliquely penetrating tunnel using eight different borehole pairs at a test site in Korea. Compared to the arrival times of the first peaks, the arrival times of the first received signals at an appropriate amplitude level provided an increasingly clear indication of the empty tunnel as its penetration angle became more oblique. A quadratic relationship between the arrival time of the first received signal and the oblique angle of the empty tunnel was obtained in pure granite. English SOC EXPLORATION GEOPHYSICISTS Estimation of the penetration angle of a man-made tunnel using time of arrival measured by short-pulse cross-borehole radar Article 10.1190/1.3374356 1 GEOPHYSICS, v.75, no.3, pp.J11 - J18 GEOPHYSICS 75 3 J11 J18 scie scopus 000278887000024 2-s2.0-84864158281 Geochemistry & Geophysics Geochemistry & Geophysics Article tunnel borehole radar