海地与智利的地震是否有关联?

Today's massive earthquake following the 7.0 quake in Haiti just last month and others recently around the globe leave us wondering if there is a pattern and more trouble ahead. We get some answers from NBC News chief science correspondent Robert Bazell.

Chile today, Haiti last month. When deadly earthquakes appear one after another, people always ask is there a connection.

"This is a very, very..."

Seismologist say no. There are earthquakes all the time.

"This sense that we are having the arrival of big ones close together, these are not actually related, they involve different pairs of plates."

Plates, those are huge sections of the Earth's crust that are in constant motion. The boundaries where they meet are called faults, and when enough pressure builds, the faults slip violently resulting an earthquake. At the sight of today's quake, one piece of Earth called the Nazca Plate is constantly pushing underneath another called the South American Plate. It is part of an enormous system of faults surrounding the Pacific Ocean called "the Ring of Fire". Today's earthquake was just 150 miles north of the biggest earthquake ever recorded, a magnitude 9.5 that killed 1,600 people in 1960 and sent huge tsunamis around the Pacific "almost half way around the world from this earthquake."

The numbers used to measure an earthquake's magnitude don't tell the whole story. Today's 8.8 quake was far more powerful than the one that struck Haiti January 12th.

"It would produce about 500 tons as much energy as a magnitude seven, so this is a much larger earthquake."

Still while everyone expects the death toll in Chile to climb, many say it will fall far short of the more than 200,000 killed in Haiti where the earthquake struck right beneath a densely-populated, poorly-built area.

"Fortunately the fault surface that ruptured and this is a little bit further from populated areas than the fault that ruptured in Haiti. So the overall shaking felt in populated areas is less."

And the tsunami warnings. When an earthquake strikes under the ocean, a tsunami occurs when the ruptured floor moves violently up and down. Today's quake moved 350 miles of ocean floor, displacing so much water that scientists predicted the waves would travel as far as Japan and Russia.

Robert Bazell, NBC News, New York.