A sharp uptick in seismic activity associated with oil and gas operations is starting to shake state regulators into pushing stiffer regulations aimed at managing earthquakes.

The renewed attention to earthquakes linked to fossil fuel production comes as federal statisticians announced last week that U.S. oil output hit a record 9.7 million barrels per day. Despite the contentions of environmental opponents, hydraulic fracturing, or fracking, itself is not the culprit for the tremors. Rather, it's the "disposal" wells used to pump wastewater from wells deep into geological formations to ensure it doesn't mix with drinking water supplies.

The key question is: Could those small tremors lead to a major earthquake? Stuart Ellsworth, an engineering manager at the Colorado Oil and Gas Conservation Commission, said two schools of thought exist: Small earthquakes relieve natural tectonic stress, or they're a precursor to a larger event. But which is correct is anyone's guess, he said.

"I don't want to discount the question, but for me that's an unanswerable question," Ellsworth told the Washington Examiner. "The earth is a very dynamic item."

State policymakers are taking no chances. Oklahoma's oil and gas regulatory agency is looking at more stringent regulations to manage seismic activity there after the Oklahoma Geological Survey said in April that it "considers it very likely" that wastewater injections explain the jump from roughly one-and-a-half magnitude 3.0 events or greater per year to 585 last year.

The Texas Railroad Commission, which oversees oil and gas regulations, hired an outside geologist to better analyze fault lines to use for proper well siting and write new rules "giving the agency the authority to amend an operator's permit up to, and including ceasing operations if necessary," Ramona Nye, a spokeswoman for the commission, told the Examiner in an email.

But some said the state regulations don't go far enough and that regulatory gaps at the federal level are slowing a response for taming the tremors.

An Interior Department rule released in March that sets new standards for fracking on federal land was silent on wastewater disposal. The Environmental Protection Agency has guidelines for disposal, but hasn't issued targeted conditions for controlling seismic activity. Critics say specifications for oil and gas operations are weaker than the other five classes of underground injection wells — state rules can supersede federal regulations as long as they meet the intent of the federal standard, called "primacy."

"The [wastewater injection] rule at the federal level doesn't address this issue at all and then obviously most of the states that have any [oil and gas disposal well] have primacy," said Briana Mordick, a staff scientist and geologist with the Natural Resources Defense Council. "The state rules don't address this issue either."

A Colorado University-Boulder study released last month found that 10 percent of the roughly 187,000 wells it surveyed occurred within 15 kilometers of earthquakes with a magnitude of 3.0 or greater. A third of those wells were for wastewater disposal, which were 1.5 times more likely to be associated with earthquakes than the "enhanced oil recovery" wells that comprised the rest of the sample. It found the number of injection wells associated with earthquakes has tripled since 2000.

Matthew Weingarten, the doctoral candidate who led the study, said it revealed the rate of injection — essentially, the pressure — makes a difference. So too does geology, as the nationwide study Weingarten's team conducted found a bulk of the activity occurred in Oklahoma and Texas. Places such as North Dakota and Pennsylvania, also epicenters of oil and natural gas drilling, didn't experience nearly as much seismic activity.

"What it says is if you have a bunch of low-rate wells that operate for long periods of times...that are properly spaced so they don't interact with each other. We actually think that is a safe away to operate the injection wells," he told the Examiner. "It really is the rate of these high-volume injection wells that we really think is driving the problem of earthquakes."

Mordick said the government should act because quakes add up and could cause damage. Earthquakes are appearing in areas that hadn't experienced them before. That means building codes and insurance plans might be outdated and current emergency plans may be unhelpful.

The EPA and Interior said they weren't planning on new regulations for seismic activity, though they didn't rule it out. The EPA in February released a document on underground injection wells that offered steps for regulators and drillers to consider to prevent triggering earthquakes.

The U.S. Geological Survey is taking some steps to guide drillers, policymakers, city planners and insurers.

In May, it released its national hazards map, which is released every five years. For the first time, the map included "new induced seismicity products" to "display intensity of potential ground shaking from induced earthquakes in a one-year period" rather than the 50-year period the hazard maps had traditionally provided. But the Geological Survey wouldn't go as far as to say the uptick in seismic activity would be the cause of a large, future earthquake.

"Small magnitude earthquakes, whether induced or natural, relieve only negligible tectonic stress compared to their larger-magnitude counterparts. An increase in the frequency of small tremors indicates that larger earthquakes may also occur somewhat more frequently. This cannot be considered a precursor, however.

Art McGarr, a research geophysicist with the U.S. Geological Survey, says: "It's just a consequence of earthquake magnitude-frequency statistics."