Bougainville is the largest island in the Solomon Islands archipelago. It is part of the Solomon Islands rain forests ecoregion. Bougainville and the nearby island of Buka are a single landmass separated by a deep 300-metre-wide strait. The island has an area of 9000 square kilometres, and there are several active, dormant or inactive volcanoes which rise to 2400 m. Bagana (1750 m) in the north central part of Bougainville is conspicuously active, spewing out smoke that is visible for many kilometres. Earthquakes are frequent, but cause little damage.