Chile Earthquake Aftershock was so great

Chile Earthquake Aftershock was so great:

Preferably 7.2-magnitude aftershock that rattled Chile today is nothing unusual weather after such a great original earthquake, scientists say.

The aftershock, which hit at about 11:40 local time, may sound very surprising, because it is larger than the original earthquake that decimated Haiti in January, but it was not unexpected for scientists, said Don Blakeman, a geophysicist with the United States Geological Survey.

The 8.8-magnitude earthquake off the coast of the Maule Region of Chile on February 27 was one of the strongest ever measured. After such a strong quake, aftershocks which themselves are substantially par for the course.

Aftershocks are usually smaller in size than the original quake, with many small aftershocks and a handful more. With an original earthquake that was more than a size 8 in "we would expect at least a couple of 7's," Blakeman told Live Science.

Aftershocks are earthquakes occur because the fault that ruptured in the initial temblor was not updating itself. They are usually within the same zone along a fault that ruptured in the original quake. And "the bigger the earthquake, the greater the aftershock zone," said Blakeman, which explains why the aftershock was not in the same place as the epicenter of the original earthquake. The fault zone for the initial quake was 250 miles (400 kilometer) long, "so it is a very large area," said Blakeman. The aftershock struck about 93 miles (150 km) southwest of the capital Santiago.

Aftershocks can last for weeks or months. They may not always occur, with periods of rest between sequences of aftershocks.

"The kind of runs in spells," said Blakeman.

Not long after the 7.2-magnitude aftershock today, a strong 6.9 aftershock shook the area again.

So far the initial Chile earthquake produced only one aftershock with a 7 in size and about 10 in between 6 and 7, Blakeman said. But "I know we had at least 150 in 5 or more range," he added.

And such great magnitude aftershock that ensures "you'll have much more after that," Blakeman said. "It's like this will have its own aftershock aftershock."

And even though it is farther away in the time of the initial earthquake, the magnitude of the aftershocks will not necessarily dispel. "We can certainly have more in the 7 range," said Blakeman.

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