Powerful earthquake rattles US state of Oklahoma
 

Powerful earthquake rattles US state of Oklahoma
http://img-s-msn-com.akamaized.net/t...6&q=60&o=f&l=fThe US state of Oklahoma experienced one of its biggest earthquakes on Saturday. But the magnitude 5.6 tremor may have been due to fracking - a process used to extract gas from deep underground. Al Jazeera’s Kimberly Halkett reports.