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 their surprise they hit volcanic rock beneath the reservoir rock, which turned out to be an extinct volcano. The gas field went in production in 1988 and is still producing gas. Another clue indicating the presence of the volcano was the temperature. While the usual temperature at that depth is about , they found . The volcano has a height of approximately and a circumference of several kilometers /miles. The volcano was formed about 160 million years ago, during a time of orogenesis on the European continent. The eruptions were short and severe with heavy explosions. This, along with the