Gyeongju earthquakes induced by North Korean underground nuclear test

Abstract

Earthquakes in 2016 Gyeongju of South Korea with magnitude of 5.8 and 633 aftershocks were induced by the fifth underground nuclear test at the Punggae-ri site of North Korea with lag times of 3 days to several months at locations consisted of Cretaceous and Jurassic granites in the Korean Peninsula. Further propagations of the seismic energies from the test site to the southern direction were blocked at Gyeongju by nearby high mountains with large pressure head due to highaltitude of above 1,000 m and heavy density of 2.76 g/cm3. Gyeongju is located at the intersection between Yangsan Fault and Ulsan Fault, whose seismic geothermal energies might propagate frequently through the channeling of northern Yangsan Fault to be released at about 4,400 geothermal venting holes (diameter 20-50 m, depth 4-6 m) in the bottom (80-240 m) of Hupo Basin with 2-4℃ allowing the famous growth of snow crab while other area of East Sea is relativelylow at 1℃. The geological feature at Gyeongju with the channeling of the Yangsan Fault toward Hupo Basin might sustain the earthquake magnitude up to M 7.73 during the last thousand years in Gyeongju even at deadly earthquakes (M 6.4 - M 6.7) since 100 AD. of Cretaceous and Jurassic granites in the Korean Peninsula. Further propagations of the seismic energies from the test site to the southern direction were blocked at Gyeongju by nearby high mountains with large pressure head due to highaltitude of above 1,000 m and heavy density of 2.76 g/cm3. Gyeongju is located at the intersection between Yangsan Fault and Ulsan Fault, whose seismic geothermal energies might propagate frequently through the channeling of northern Yangsan Fault to be released at about 4,400 geothermal venting holes (diameter 20-50 m, depth 4-6 m) in the bottom (80-240 m) of Hupo Basin with 2-4℃ allowing the famous growth of snow crab while other area of East Sea is relativelylow at 1℃. The geological feature at Gyeongju with the channeling of the Yangsan Fault toward Hupo Basin might sustain the earthquake magnitude up to M 7.73 during the last thousand years in Gyeongju even at deadly earthquakes (M 6.4 - M 6.7) since 100 AD.