Reactivated Fault Lines Could Trigger Larger Oklahoma Earthquakes, Study Says

Residents of central Oklahoma have become familiar with the ground shaking in the last few years, but it could all lead to something bigger and more damaging, according to geologists. The findings of a new study, published recently in Geophysical Research Letters, reveals that thousands of small, shallow earthquakes along the state's strike-slip faults may have reactivated fault lines that are capable of major tremors. That's because the direction these fault lines are facing don't line up with the direction of regional tectonic stress in the planet's upper crust, increasing the probability of a large quake, the U.S. Geological Survey (USGS) says.

The study did not investigate whether hydraulic fracturing – better known as fracking – was causing the faults to be reactivated. 

Any larger earthquake could be worsened by the fact that building codes in Oklahoma aren't as strict as areas like California, Reuters reported. That's especially worrisome because there are as many as 12 fault zones capable of triggering a magnitude-5 or -6 earthquake. More than a dozen homes and multiple businesses sustained damage from a 5.6-magnitude temblor back in 2011. Last year there were 5,417 earthquakes in Oklahoma, and 585 of those quakes were magnitude-3 or larger, according the Oklahoma Geological Survey,

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