South Korea most of which is not arable. Lowlands, located primarily in the west and southeast, make up only 30% of the total land area. About three thousand islands, mostly small and uninhabited, lie off the western and southern coasts of South Korea. Jeju-do is about off the southern coast of South Korea. It is the country's largest island, with an area of . Jeju is also the site of South Korea's highest point: Hallasan, an extinct volcano, reaches above sea level. The easternmost islands of South Korea include Ulleungdo and Liancourt Rocks (Dokdo/Takeshima), while Marado and Socotra Rock are the southernmost
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.