Jeju uprising to Jeju from Busan and deploying police companies, each 1,700 strong, from the southern provinces of the mainland. The guerrillas retreated to their bases in the forests and caves around Hallasan, an extinct volcano and the highest mountain in South Korea. On April 29, the Korean, non-military, governor of Jeju province abandoned his post, defected, and joined the guerrillas. This caused many police officers, disillusioned by the atrocities they were ordered to commit against their own, to do the same. In response, U.S. military provincial governor William F. Dean ordered a purge of SKLP sympathizers from the ranks of the
Zuidwal volcano mineral composition, points to volcanic activity as a result of subduction far away from the volcano. During the Cimmerian Orogeny, the Cimmerian Plate collided with Kazakhstania, sending shock waves through the Eurasian Plate, resulting in volcanism. The volcano is covered by layers of sandstone from the early Cretaceous that act as reservoir rock for the gas. The seal rock consists of shale. The volcanic rock is magnetic, creating a magnetic anomaly. Zuidwal volcano The Zuidwal volcano is an extinct volcano in the Netherlands at more than below ground under the Wadden Sea, between Harlingen and Vlieland, just south west of