<html><head><meta http-equiv="Content-Type" content="text/html charset=windows-1252"><meta http-equiv="Content-Type" content="text/html charset=windows-1252"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"><div><span style="line-height: 26px; background-color: rgb(255, 255, 255);">Whereas California’s quakes are spread throughout the state, seismic activity in Oklahoma is concentrated in the central and northern part of the state — areas where oil and gas drilling, otherwise known as hydraulic fracturing or </span><a href="http://america.aljazeera.com/topics/topic/issue/Fracking.html" style="box-sizing: border-box; color: rgb(38, 119, 185); text-decoration: none; line-height: 26px; background-color: rgb(255, 255, 255);">fracking</a><span style="line-height: 26px; background-color: rgb(255, 255, 255);">, has increased in recent years. In Oklahoma as a whole, drilling doubled between 2009 and 2012. </span></div><a href="http://america.aljazeera.com/articles/2014/6/26/oklahoma-new-earthquakecapitaloflower48.html">http://america.aljazeera.com/articles/2014/6/26/oklahoma-new-earthquakecapitaloflower48.html</a><div><br></div></body></html>