How High is Mauna Loa?
Groups of students of all ages frequently visit the U.S. Geological Survey’s Hawaiian Volcano Observatory while they are on an excursion to Hawaii Volcanoes National Park. When prior arrangements are made, we escort them around our facilities and give a short talk on our mission and program. On clear days we are able to see Mauna Loa and often include information about this majestic volcano in our talk. Most of the students are aware that Mauna Loa is the largest volcano in the world, but most are surprised that it is also the highest from base to summit. Its gentle slope and shield-like shape belie the greatness of this edifice. The heights of mountains are generally given by their elevation above a datum, such as sea level. The highest point on Mauna Loa is 4,170 m (13,680 ft) above sea level. But the flanks of Mauna Loa continue another 5,000 m (16,400 ft) below sea level to the sea floor. The massive central portion of the volcano has depressed the sea floor another 8,000 m (26,000
