Hallasan National Park (9.6 km), Seokgulam Trail (1.5 km), Gwaneumsa Trail (8.7 km), Donnaeko Trail (7 km), and Eoseungsaengak Trail (1.3 km). The longest trail is Seongpanak Trail which takes about 4.5 hours. Hallasan comprises 153.112 km of the Jeju Island. It rises 1.950 m above the sea level which means the highest mountain in South Korea. This mountain was formed in the fourth Cenozoic era by outburst of volcano. It is mostly composed of basalts. It is extending east and west, and it has high and gradual descent. On the other hand, the south part of the mountain is steep. In the
Nemrut (volcano) many measurements and observations. He also suggested possible ways of the evolution of Nemrut, most of which were confirmed later. In the 20th century, the scientific study of the volcano was interrupted by the political instability in the region. In the first half of the 20th century Nemrut was wrongly classified as an extinct volcano. Only in the 1980s, with the resumption of the studies, its status was changed to dormant. Currently Nemrut is mainly studied by Turkish volcanologists. The volcano is still poorly understood, and there is no consensus on the interpretation of stratigraphic data. Analysis of the sediments