Dom João de Castro Bank (also known as Don João de Castro Bank) is a large submarine volcano in the Azores in the central Atlantic Ocean. The volcano lies midway between the islands of Terceira and São Miguel and rises to within 14 m of the sea surface. The volcano has a large fumarole field and remains seismically active. It last erupted in December 1720, forming an island of 1.5 km in length and about 250 m in altitude. It remained above sea level for only two years, before rapid erosion reduced its height. Two parasitic craters, both about 90 x 45 m (300 x 150 ft) wide, are located on the northwest flank. The younger crater displays a floor consisting of a chilled lava lake with polygonal surface fractures, while the older, less distinct crater is obscured by tephra deposits.