An evaluation of terrain characteristics provides a way to make geologic interpretations for denied-access sites. This contribution illustrates the utility of this approach by developing a revised geologic map of the North Korean test site through reconnaissance-based geomorphometrics (defined as the science of quantitative land surface analysis) and geospatial investigation. This study provides a way to quantify the geologic differences at the test site and suggests that geologic factors contributed to the prompt release of detected radionuclides associated with the 2006 nuclear test event compared to the 2009 and 2013 events. This method is relevant for test monitoring by providing: 1) A better understanding of host rock integrity and geologic coupling characteristics; 2) A means to facilitate a more accurate determination of explosive yields; 3) A better understanding of event containment and the likelihood of venting, and 4) An enhanced understanding of potential radionuclide transport mechanisms that might assist in future monitoring and verification of clandestine tests.