Landslide, mudslide, debris flow–it doesn't matter what you call it, the outcome is the same: normally stable and stationary soil gets a bad case of wanderlust. In most cases, slides are triggered when too much water saturates a steep slope or when an earthquake shakes the ground loose. This can occur almost anywhere, but Central America–with its precipitous hills, frequent heavy rainstorms and unstable volcanic soil–is probably the number one hotspot. Ed Harp, a landslide geologist with the U.S.

Humans are fleeting visitors on this roiling rock in the universe. On December 26, 2004, at 58 minutes and 49 seconds past midnight GMT, Mother Earth reacquainted us with this immutable fact. For millions of years, a creeping slab of Earth’s crust—the India Plate—had been grinding headlong into a similarly stubborn chunk of rock called the Burma Plate. Like a clash of Brobdingnagian armies, millennia of pent-up kinetic energy suddenly exploded from the seabed, a scant 100 miles from Sumatra, Indonesia.