In April 2012, a study by scientists at the US Geological Survey of the interior of the US found that events of magnitude 3 or greater had "abruptly increased in 2009" from 1.2 per year in the previous 50 years to more than 25 per year - although a number of gas and oil extractionmethods may be implicated in the rise.
This resource requires special extractionmethods to get it out of the ground and into a form where it is fluid enough to travel down the pipelines for refining into gasoline and other hydrocarbon products.
But critics of human cloning and stem cell extractionmethods essentially believe a human egg that begins to divide for any reason should be considered an embryo, and a potential person, that deserves protection under the law.