How Volcanoes Work

 Image Described in Caption
 Mauna Loa -- The shield volcano shape of Mauna Loa is evident in this view of the mountain from the southeast. Located on the "Big Island" of Hawaii, the elevation of its summit rises to over 4000 m above sea level, 3000 m higher than the adjacent Kilauea volcano, whose summit caldera is visible in the lower left. The Hualalia volcano is visible in the upper right. Kilauea has recently been the most active of these volcanoes with near constant eruptions of basaltic lava over the past sixteen years. Mauna Loa last erupted in 1984; however, its eruptions historically have been much more voluminous than those at Kilauea. Courtesy of J.D. Griggs, USGS.