There has been an increase in the number of earthquakes reported in the last decade. I quoted the same from an article in one of my recent posts.
The next three years saw a far greater increase in such events. The time period corresponds to a boom in natural gas production, made possible by the use of hydraulic fracturing. There were 50 earthquakes in 2009, 87 in 2010 and 134 last year.
I came across the following article on this website.
Are Earthquakes Really on the Increase?
We continue to be asked by many people throughout the world if earthquakes are on the increase. Although it may seem that we are having more earthquakes, earthquakes of magnitude 7.0 or greater have remained fairly constant.
A partial explanation may lie in the fact that in the last twenty years, we have definitely had an increase in the number of earthquakes we have been able to locate each year. This is because of the tremendous increase in the number of seismograph stations in the world and the many improvements in global communications. In 1931, there were about 350 stations operating in the world; today, there are more than 8,000 stations and the data now comes in rapidly from these stations by electronic mail, internet and satellite. This increase in the number of stations and the more timely receipt of data has allowed us and other seismological centers to locate earthquakes more rapidly and to locate many small earthquakes which were undetected in earlier years. The NEIC now locates about 20,000 earthquakes each year or approximately 50 per day. Also, because of the improvements in communications and the increased interest in the environment and natural disasters, the public now learns about more earthquakes.
According to long-term records (since about 1900), we expect about 17 major earthquakes (7.0 - 7.9) and one great earthquake (8.0 or above) in any given year.
This article makes it clear that even when those who insinuate to the 2012 phenomenon using this increased frequency of locating earthquakes, we should keep an open mind and investigate as long as possible.
But a question which is not yet answered is: Is the rate of increase in the frequency of earthquakes in the years reported( 2009, 2010, 2011) constant and similar to the rate between other years?
Image Source: http://www.geo2all.com/vb/showthread.php?1697-How-Earthquakes-Work