vailulu'u is a volcanic seamount discovered in 1975. it rises from the sea floor to a depth of 593 m and is located between ta'u and rose islands at the eastern end of the samoa hotspot chain. the basaltic seamount is considered to mark the current location of the samoa hotspot. the summit of vailulu'u contains a 2 km wide, 400 m deep oval-shaped caldera. two principal rift zones extend east and west from the summit, parallel to the trend of the samoan hotspot. a third less prominent rift extends southeast of the summit.