天皇海山群
Volcano flanks can become over-steep resulting in instability and mass wasting. This is now a recognised part of the growth of all active volcanoes. It is seen on submarine volcanoes as well as surface volcanoes: Loihi in the Hawaiian–Emperor seamount chain and Kick 'em Jenny in the Lesser Antilles Volcanic Arc are two submarine volcanoes that are known to undergo mass wasting. The failure of the northern flank of Mount St Helens in 1980 showed how rapidly volcanic flanks can deform and fail.