Drilling rigs are pictured near Calumet, Okla., April 12, 2013. Sue Ogrocki/AP

The Red Cross is offering a free earthquake app to Oklahomans after 150 small earthquakes hit the state in just the past week, according to the state’s geological observatory. The app gives users earthquake notifications and allows them to monitor activity where friends and family reside, Ken Garcia, a Red Cross spokesman for Central and Western Oklahoma, told Al Jazeera. "The way it works is you can set it to your current location — on mine I have it set for Oklahoma City and it has a 250-mile radius," Garcia said. Included in the app are simple checklists to create a family emergency plan, locations of Red Cross shelters, information on what could happen after earthquakes — such as fire and tsunamis, and a toolkit with flashlight, strobe light and audible alarm. The app was released nationwide in September 2012, but since it can be personalized to any location, it was recommended to Oklahomans after a significant increase in the frequency and intensity of earthquakes was reported in the state. Some geologists believe activities related to hydraulic fracturing, or ‘fracking’ — injecting water, sand, and a cocktail of toxic chemicals under high pressure into bedrock to increase the flow of oil or gas — could be to blame for the unusual seismic activity. The U.S. Geological Survey (USGS) said their studies show the average number of earthquakes of magnitude 3.0 or larger annually in Oklahoma jumped from three between 1975 and 2008 to 40 from 2009 to mid-2013. “We’ve statistically analyzed the recent earthquake rate changes and found that they do not seem to be due to typical, random fluctuations in natural seismicity rates,” Bill Leith, USGS seismologist, said

Wastewater disposal

The USGS analysis suggested that wastewater disposal from oil and gas fracking — instead of the process of fracking itself — could be a contributing factor to the increase in earthquakes. Other scientists have echoed that theory. Since 2009 in Oklahoma, alongside earthquakes, the volume of wastewater injected into underground disposal wells had risen – up 50 percent in 2012 from the level seen during most of the 2000s. Oklahoma has more than 4,000 disposal wells for waste from the state’s tens of thousands of oil and gas wells. “Most of the earthquakes in Oklahoma are likely not related to fracking. They are likely related to a different practice in oil and gas production, which is wastewater disposal,” Katie Keranen, Assistant Professor of Geophysics at Cornell University, told Al Jazeera. “There is considerable evidence to link the injection wells to the earthquakes." In Oklahoma, Keranen said, when the oil and gas is pumped out, so is an unusually large volume of wastewater, which is then put back underground in a different place. A study by USGS found that wastewater injection increases pressure underground, which may lubricate and weaken nearby faults. If the pressure increases enough, the weakened fault will slip, causing an earthquake. But fracking, the study adds, is rarely the direct cause of such seismic activity. An Oklahoma Geological Survey statement Monday said, “The OGS has not ruled out that some earthquakes may have a relationship to oil and gas activities.” In nearby Arkansas, a group of homeowners who filed lawsuits against well operators alleged that their properties were damaged by earthquakes that hit the region in 2010 and 2011. Scientists there blamed disposal wells for touching off more than 1,000 quakes in those years.

String of accidents