Solid Earth dynamics video

Ice is heavy when it covers large swaths of continents, as it did during the last ice age. As these ice sheets melted, Earth’s crust responded to the redistribution of mass on its surface by rising where the ice sheets previously resided – a rebounding process that is still occurring in some areas. Other areas are sinking—or subsiding—in response to the rebound, like the other end of a seesaw. Credit: NASA