Belknap Crater
Belknap formed on the lower slopes of Mount Washington, a highly eroded volcano; Mount Washington's pinnacle lies about from Belknap. Dissolved magmatic carbon dioxide flux at Mount Washington and Belknap Crater was calculated by James et al. (1999) to be per year. Belknap consists of a shield volcano and pyroclastic cone, which form a late Holocene shield volcano complex. It is made up of basaltic and basaltic andesite lava, which is sub-alkaline. Mafic in composition, it is characteristic of High Cascade volcanism. In addition to its shield volcano vents, the Belknap complex also consists of lava flows and tephra deposits erupted from one central vent and several other flank vents. Its lava flows encompass about . It has a pyroclastic core. The more southern of the two craters on Belknap's summit cone has a depth of and width of more than at its rim.