While most earthquakes last for only a few seconds, it is reported that the Sumatra-Andaman earthquake, as it is known to the scientific community, lasted almost ten minutes, triggering other earthquakes as far away as Alaska and causing the entire planet to move at least a few centimeters. The epicenter of the earthquake was 100 miles west of Sumatra, at the western end of the area known as the “Ring of Fire” for its intense seismic activity. That region has been home to more than 80 percent of the world’s largest earthquakes. Since 1900, when accurate measurements began to be made, only three or four earthquakes have rivaled the Sumatra-Andaman in power (see History Channel, for more information).
The earthquake was the result of the sliding of the portion of the Earth's crust known as the India plate under the section called the Burma plate. The process has been going on for millennia, one plate pushing against the other until something has to give. The result on December 26 was a rupture the USGS estimates was more than 600 miles (1,000 kilometers) long, displacing the seafloor above the rupture by perhaps 10 yards (about 10 meters) horizontally and several yards vertically. That doesn't sound like much, but the trillions of tons of rock that were moved along hundreds of miles caused the planet to shudder with the largest magnitude earthquake in 40 years.