 In Iceland, volcanic vents, which can be long fissures, often open parallel to the rift zones where the Eurasian and the North American Plate lithospheric plates are diverging, a system which is part of the Mid-Atlantic Ridge.Renewed eruptions generally occur from new parallel fractures offset by a few hundred to thousands of metres from the earlier fissures.This distribution of vents and sometimes voluminous eruptions of fluid basaltic lava usually builds up a thick lava plateau, rather than a single volcanic edifice.