Oklahoma had more earthquakes in 2015—more than 900 of magnitude 3.0 or higher—than the combined total of every state except Alaska. Before the oil and gas boom that began in 2009, Oklahoma averaged two earthquakes of magnitude 3.0 or higher per year. Oklahoma, which had 701 earthquakes of 2.8 magnitude or higher through the first six months of 2015, had 619 during that time period this year. (Stateline graphic: Oklahoma earthquakes)
"To gather more data, Oklahoma, Pennsylvania and Texas are expanding their seismic monitoring systems this year, placing permanent stations across the states and moving temporary stations to new hotspots," Fifield writes. "And Oklahoma and Texas hired more staff or are contracting with scientists to study the geology of areas where earthquakes are occurring, the details of the quakes that happen, and the oil and gas activity that may be associated with them."
"About 7 million people across the Central and Eastern U.S. are now at risk of man-made shaking powerful enough to crack walls and rattle items off shelves, according to a one-year United States Geological Survey forecast released in March," Fifield writes. "The report outlined the risk from man-made earthquakes for the first time, listing the states with the highest risk in order as Oklahoma, Kansas, Texas, Colorado, New Mexico and Arkansas." (Read more)