Seismic Experts Expect Much Bigger Earthquake in Chile Than the 8.2 Temblor of April 1

[node:summary]An 8.2-magnitude earthquake off Chile on April 1 is not the worst in store for the region, seismologists said.

The 8.2-magnitude earthquake off Iquique, Chile that killed six people and sparked a tsunami, prompting the evacuations of thousands along much of the South American Pacific coast, was not the so-called big one that seismic experts have been warning about, the Associated Press reported on April 2.

The tsunami was large enough at more than six feet to lift fishing boats onto the streets of the northern port city, AP reported, and sunk others. Chilean President Michele Bachelet declared a state of emergency in the affected region, and tsunami warnings were at first issued along the Pacific as far north as Hawaii. Two-foot waves from the tsunami did reach Hawaii, the Weather Channel reported.

After 10 hours, Chileans were allowed to return to their homes, and officials expressed relief that the damage was not worse. Six people died, some crushed to death by falling debris and others from heart attacks, AP said. The temblor, occurring on April 1 at 8:46 p.m., sent rocks tumbling onto roads and cut power to thousands of people and starting numerous fires, AP said. Adobe houses were damaged or destroyed in the city of Arica, also close to the epicenter, the news wire said.

The quake hit at a shallow 12.5 miles below the Pacific Ocean, about 60 miles northwest of the mining port town, a major copper-producing region that lies near the border with Peru, the U.S. Geological Survey said.

There had been several smaller earthquakes in the normally quiet region over the past several weeks, and aftershocks have been plentiful since the 8.2-magnitude temblor that struck on Tuesday, with more than 20 striking, including a magnitude 6.2.

That said, seismic experts told AP that much more is expected given the length of time that has passed since the last major quake—140 years ago, in 1877, an 8.8-magnitude caused a tsunami along the Chile-Peru coast and killed people as far away as Hawaii and Japan—and the distance the major plates in the area have moved.

"This is the one remaining gap that hasn't had an earthquake in the last 140 years," USGS seismologist Mike Simons told AP. "We know these two plates come together at about six, seven centimeters a year, and if you multiply that by 140 years then the plates should have moved about 11 meters along the fault, and you can make an estimate of the size of earthquake we expect here."

This could happen “tomorrow, could be in 50 years; we do not know when it's going to occur,” he said. “But the key point here is that this magnitude-8.2 is not the large earthquake that we were expecting for this area. We're actually still expecting potentially an even larger earthquake.”