Height: 452 meters, Type: Shield volcano, Status: Holocene. Shield volcano 452 m. An area of extensive basaltic lava flows occupies a graben, the NNE-SSW-trending Ch’uga-ryong rift, that cuts diagonally across the demilitarized zone between North and South Korea. One 40-km-long lava flow originated from the low Ap-san shield volcano, which has a 200-m-wide summit crater and more than 20 satellitic cones. Another voluminous late-Pleistocene lava flow is 60 km long. Alkaline basaltic lava flows at the SW portion of the rift were erupted over Precambrian sediments and igneous rocks, and were estimated by Lee (1981) to be late-Pleistocene or early Holocene in age.