The powerful earthquake that rocked Chile in April ruptured the planet in a way that suggests major quakes may hit the region again, researchers say.
On April 1, a magnitude-8.2 earthquake struck about 58 miles (94 kilometers) northwest of Iquique in northern Chile. It killed six people, damaged thousands of homes and triggered a tsunami wave nearly 7 feet (2.1 meters) high. Economic losses have been estimated at close to $100 million.
The earthquake originated in a seismic hot spot that has produced some of the world's strongest tremors. The area is a subduction zone, where one tectonic plate dives beneath another — specifically, the oceanic Nazca Plate is plowing under the Pacific coast of the South American Plate at an average rate of 2.75 inches (7 centimeters) per year. [In Photos: This Millennium's Destructive Earthquakes]
The last time a great earthquake happened in this area was in 1877, when a magnitude-8.8 quake ruptured nearly 310 miles (500 kilometers) of a fault.
"We had known about the potential for a large event in this region for some time," said Gavin Hayes, a seismologist at the U.S. Geological Survey and lead author of one of two studies about the 2014 Chile quake in Thursday's issue of the journal Nature.
The researchers said the 2014 quake was smaller than the shock they had anticipated. "There is still a lot of stored strain in this subduction zone, meaning the hazard still remains," Hayes said.
In a separate Nature study, Bernd Schurr at the German Research Center for Geosciences and his colleagues found that the 2014 quake broke a 93-mile-long (150-kilometer-long) portion in the center of the seismic gap. However, only one-third of the seismic gap was broken. Two large segments north and south of the ruptured portion remain, and they pose a significant hazard.
Update: The U.S. Geological Survey said a magnitude-5.7 earthquake occurred near Iquique at 8:02 p.m. ET Wednesday.