When a massive iceberg breaks off from the front of a glacier it can fall backwards, slamming into the glacier with such force that it reverses the ice flow for several minutes and causes it to drop, producing an earthquake that can be measured across the globe.
The journal Science is publishing the discovery, including detailed documentation of the forces involved in these iceberg calving events and an explanation for the causes of glacial earthquakes. The research marks a major step toward the ability to measure the size of iceberg calving events in near real-time and from anywhere in the world.
“Glaciers are extremely sensitive indicators of climate change,” says co-author Justin Burton, a physicist at Emory University who specializes in laboratory modeling of glacial forces. “Having a quantitative understanding of how our polar regions are losing ice is crucial to any forecasting related to climate change, in particular sea-level rise and its environmental and economic impacts.”
The study, which focused on Helheim Glacier in the Greenland Ice Sheet, also included scientists from the universities of Swansea, Newcastle and Sheffield in the UK and the universities of Columbia and Michigan in the U.S.