rift zone

rift zone

Aerial view of the northeast rift zone of Mauna Loa Volcano, Hawai'i. Dark lava flows spread away from the rift zone. Credit: J. P. Lockwood / U.S. Geological Survey.

A rift zone is an elongate system of crustal fractures associated with an area that has undergone extension (ground has spread apart). On the great shield volcanoes in Hawai'i, a rift zone consists of many different features associated with the rise and eruption of magma from narrow dikes, including eruptive fissures, cinder and spatter cones, spatter ramparts, pit craters, lava flows, ground cracks, and normal faults.