Earthquake

Along with the geological shock, it's also an emotional shock when earthquakes like the one that just hit Chile occur.  But while we extend a hand and grieve with victims, we must also keep in mind that these happen frequently. 

The United States Geological Survey estimates that, since 1900, there have been an average of 18 major earthquakes (magnitude 7.0-7.9) and one great earthquake (magnitude 8.0 or greater) per year somewhere in the world, and that this average has been relatively stable.  Furthermore, most of the world's earthquakes (90%, and 81% of the largest) take place in the 40,000-km-long, horseshoe-shaped zone called the circum-Pacific seismic belt, also known as the Pacific Ring of Fire, which for the most part bounds the Pacific Plate.  That means the Pacific coast of South and Central America, California, Alaska, Japan, and Indonesia.

Finally, it's helpful to note that the world's largest earthquake known to date, registering 9.0 on the Richter occured in 1960 just a couple of hundred miles south of today's earthquake.

To help put Chile's earthquake in further perspective, below are two maps: one historical map of earthquakes over just the last 50 years, and the other a map of plate tectonics: