is an active stratovolcano

Stratovolcano

A stratovolcano, also known as a composite volcano, is a tall, conical volcano built up by many layers of hardened lava, tephra, pumice, and volcanic ash. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile and periodic, explosive eruptions...

 in the Shikotsu-Toya National Park

Shikotsu-Toya National Park

is a national park in the central part of the island of Hokkaidō, Japan. Named after the volcanic caldera lakes of Lake Shikotsu and Lake Tōya, it has a total area of 993.02 square kilometers...

, Hokkaidō

Hokkaido

, formerly known as Ezo, Yezo, Yeso, or Yesso, is Japan's second largest island; it is also the largest and northernmost of Japan's 47 prefectural-level subdivisions. The Tsugaru Strait separates Hokkaido from Honshu, although the two islands are connected by the underwater railway Seikan Tunnel...

, Japan

Japan

Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

. It has erupted four times since 1900: in 1910, 1944–45 (which created Showashinzan

Showashinzan

is a volcanic lava dome in the Shikotsu-Toya National Park, Hokkaidō, Japan, next to Mount Usu. The mountain was created between 1944 and 1945. Initially, a series of strong earthquakes shook the area, and wheat fields were rapidly uplifted. Lava broke through the surface and the current peak...

), August 7, 1977, and on March 31, 2000. To the north lies Lake Toya

Lake Toya

is a volcanic caldera lake in Shikotsu-Toya National Park, Abuta District, Hokkaidō, Japan. The stratovolcano of Mount Usu lies on the southern rim of the caldera. The lake is nearly circular, being 10 kilometers in diameter from east-west and 9 kilometers from North-South. The lakes biggest town,...

. Mount Usu formed on the southern rim of the caldera

Caldera

A caldera is a cauldron-like volcanic feature usually formed by the collapse of land following a volcanic eruption, such as the one at Yellowstone National Park in the US. They are sometimes confused with volcanic craters...

 containing the lake.

Mount Usu and Showashinzan are major tourist attractions in the Shikotsu-Toya National Park

Shikotsu-Toya National Park

is a national park in the central part of the island of Hokkaidō, Japan. Named after the volcanic caldera lakes of Lake Shikotsu and Lake Tōya, it has a total area of 993.02 square kilometers...

. A ropeway on Mount Usu takes visitors to viewing platforms overlooking Showashinzan.