Hallasan Hallasan Hallasan is a shield volcano on Jeju Island of South Korea. It is the highest mountain in South Korea. The area around the mountain is a designated national park, the Hallasan National Park ("Hallasan Gungnip Gongwon"/한라산국립공원/). Hallasan is commonly considered to be one of the three main mountains of South Korea, along with Jirisan and Seoraksan. Hallasan is the highest mountain in South Korea and is worshipped by people because they think that gods and spirits live on it. Alternate English names for the mountain include Hanla Mountain or Mount Halla and older English sources refer to the peak
Lascar (volcano) trend that includes Aguas Calientes. Six craters are located on the volcano, but sometimes only five craters are counted, in which case the central crater is considered to be the active one. The extinct western cone (also known as Apagado) is composed of layers of lava and pyroclastics. Its large crater is filled by another cone, which forms the highest summit of the Lascar volcano. Immediately east of it lies the eastern cone, which is contiguous with the western cone. The eastern cone (also known as Activo) is capped off with three distinct craters which are delimited by arcuate fractures.