Mauna Loa is the largest volcano on our planet—the summit elevation is 4,170 m (over 13,600 ft), but the volcano’s summit rises 9 km above the sea floor. The sharp features of the summit caldera and lava flows that drain outward from the summit are tribute to the fact that Mauna Loa is one of the Earth’s most active volcanoes. The most recent eruption was in 1984. The straight line the cuts through the center of the crater from top to bottom is a rift zone—an area that pulls apart as magma reaches the surface.
his image shows the results of previous eruptive activity at Kilauea’s main crater and the Mauna Ulu crater on the volcano’s flank. A close look at the bare rock around the volcanoes reveals rivulets of rock, slightly darker than their surroundings, flowing from both craters toward the coast. In between areas of bare lava, vegetation has managed to thrive.