Bougainville Island is the main island of the Autonomous Region of Bougainville of Papua New Guinea. This region is also known as Bougainville Province or the North Solomons. The population of the province is 175,160 (2000 census), which includes the adjacent island of Buka and assorted outlying islands including the Carterets. Although Bougainville Island is geographically part of the Solomon Islands archipelago, the nation of the Solomon Islands is a separate state. Bougainville and the nearby island of Buka are a single landmass separated by a deep 300-metre-wide strait. The island is 9000 square kilometres, and there are several active, dormant or inactive volcanoes which rise to 2400m. Mount Bagana in the north central part of Bougainville is conspicuously active, spewing out smoke that is visible many kilometres distant. Earthquakes are frequent, but cause little damage.