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March 8, 2010

Dynamic Earth: An Abundance of Earthquakes?

It's only the beginning of March, but 2010 already seems like a terrible year for earthquakes. First, on January 12, there was the 7.0 earthquake just off the coast of Haiti. Then Japan was hit with a 7.0 earthquake. Last Saturday, Chile was hit with an 8.8 earthquake, the fifth strongest ever recorded. And just today 5.9 earthquake occurred in Turkey. It's causing a lot of people to wonder, "What's going on?"

Despite the amount of news coverage for earthquakes all of a sudden, though, this year isn't really more severe than any other. Earthquakes are quite a common event. According to the USGS, there is a 100% chance of some magnitude of an earthquake occurring somewhere on planet Earth every day. 

The magnitude of the earthquakes occurring this year is not out of the ordinary, either. The annual number of earthquakes, also according to the USGS, is:

MagnitudeAverage Annually
              8 and higher             1 ¹
              7 - 7.9            17 ²
              6 - 6.9           134 ²
              5 - 5.9          1319 ²
              4 - 4.9         13,000
              3 - 3.9        130,000
              2 - 2.9       1,300,000

¹ Based on observations since 1900.
² Based on observations since 1990.
The only thing that makes this year uncommon is how much damage to people earthquakes have done this year. Fortunately for us, most of the severe earthquakes don't hit populated areas. This year, that hasn't been the case. Over 200,000 people were killed in the Haitian earthquake, and thousands to millions more were affected. The Chilean earthquake killed around 200. It also affected the rotation of the entire planet, shortening the length of the day by 1.26 milliseconds. There are 57 confirmed deaths from the earthquake today in Turkey. This year is no worse than normal for earthquakes. It is only the impact of these earthquakes that is more noticeable than usual. The world is not shaking itself to bits; it's just moving, same as it always does.

Source: USGS Earthquakes
More information on earthquakes in general