Interpretation of Heat Flow Characteristics of Korea

Abstract

A total of 359 heat flow values have been estimated in Korea since 1970. The mean geothermal gradient of Korea is 25.1C/km; the mean heat flow of Korea is 60±11 mW/m2. High heat flow values appear in Asan, Boryeong, Yuseong, Jinan, Uljin, Pohang, Busan, Pocheon, Sokcho, Chungju, and Suanbo. Those high heat flow areas are in agreement with the locations of hot springs in Korea. The southeastern part of Korea shows high heat flow distribution that is likely to be associated with the faults (Yangsan fault, Milyang fault, Moryang fault, Dongrae fault and so on). Those faults probably play as a conduit for geothermal fluids.

Using a GIS software, we investigated the relationship between geological information (rock type, geological time, Moho depth) and surface heat flow. In the aspect of the lithology, there is no significant heat flow difference in different rock types. The area of sedimentary rock shows heat flow of 71 mW/m2, the sedimentary/volcanic rock area 68 mW/m2, the plutonic rock area 67 mW/m2, and the metamorphic rock area 62 mW/m2. In the geological time sequence, the Cenozoic strata contains heat flow of 78 mW/m2, the Mesozoic 68 mW/m2, the Paleozoic strata 65 mW/m2, the Proterozoic strata 67 mW/m2, and the Archean strata 62 mW/m2. In terms of Moho depth, the shallow Moho depth area tends to have higher heat flow values than the area of the thick crust.