The goal of this study was to examine the danger of six North Korean underground nuclear tests to the regional safety associated with deadly earthquakes and volcanoes. Geological instabilities at Cretaceous granites were triggered by North Korean nuclear tests to induce the enhanced seismic impacts on earthquakes in China, Russia, Japan, Taiwan (China), South Korea, USA, Ecuador, Vanuatu, Indonesia, and Mexico after lag times between the nuclear test site and individual epicenters. It is urgent to prohibit North Korean nuclear tests for the regional stability of surrounding countries with Cretaceous granites.