Measuring a Changing Volcano

Measuring a Changing Volcano Open Novice Optional Files 1 One Pager: Changing Volcano Open Resource This hands-on demonstration illustrates how GPS can be used to measure the inflation and deflation of a volcano. It also shows how the rocks at the summit of a volcano weaken and crack to form a crater or caldera as the volcano inflates and deflates. The difference between a volcanic caldera and a volcanic crater is that calderas are really wide, often more than a mile in diameter. The Yellowstone caldera is approximately 50 miles (80 km) long and 40 miles (65 km) wide! Objectives: Students will measure changes at the surface of the physical model of a volcano to understand how GPS stations are used to measure volcanic deformation. Keypoints: Volcanic craters and calderas can form by the collapse of the rock near the summit without an eruption. Volcanoes inflate (pressurize) and deflate (depressurize) without necessarily erupting (diagram below). We can understand what’s going on inside a volcano by measuring changes at the surface, even a few millimeters of movement, using GPS. Most craters form slowly over time as the volcano inflates and deflates, deforming and weakening the rocks near the summit. The volcano’s magma chamber is made up of spongelike rock. One Pager: Measuring a Changing Volcano Miscellaneous Novice Click on the image to the right. One Pager: Measuring a Changing Volcano Miscellaneous Novice We encourage the reuse and dissemination of the material on this site as long as attribution is retained. To this end the material on this site, unless otherwise noted, is offered under Creative Commons Attribution ( CC BY 4.0 ) license