First, there was a little rumble. A bit later came the roar.

At the Cripple Creek Stoneyard in Crescent, Oklahoma, clocks fell off the walls, and the office bounced on its slab. At Hometown Foods, the shelves swayed from side to side, tossing cans onto the floor.

"It shook stock off every aisle," Hometown co-owner Brian Johnston told VICE News. "It was getting bigger and shaking harder. I was like, 'Crap, this is it.' "

Welcome to Quakelahoma, where in less than a decade the state has gone from having about two noticeable earthquakes a year to about two a day. In 2014, geologists recorded 585 tremors of magnitude 3.0 or higher, and 2015 has already topped that mark. Scientists warn the state is at risk of a major earthquake, and the financial industry is starting to ponder the potential losses.

They're not the threat to life and limb posed by natural hazards like tornadoes, which have killed dozens of people at a time in Oklahoma. But the difference between tornadoes and the Sooner State's seismic surge is that nearly all of today's quakes are believed to be man-made — triggered by injecting briny wastewater from oil wells deep underground.

The quakes haven't killed anyone. Not yet, some here are quick to add. But they're increasingly more than an irritation.

"When you start losing merchandise and start having to fix stuff, that's when you start getting pissed off, you know what I'm saying?" Crescent businessman Mike Logan told VICE News.

Brian Johnston (L) and Jeff Holley (R) are co-owners of Hometown Foods which was hit heavily by an earthquake.

An oil rig on the outskirts of Crescent, OK.

About half a dozen noticeable quakes hit the town of about 1,200 on July 27. They were all centered within about a mile of Cripple Creek Stoneyard, about 30 miles north of Oklahoma City, in an area where three wastewater injection wells were operating.

"If you're standing here, and vroom, a semi just drove right by you — I mean, right next to you - that's what it sounds like," said Logan, who co-owns the stoneyard with Marvin Schwartz, who has a house on the property. The quakes left cracks in the bedroom walls and in a storage room, knocked the dishes out of his cabinets and his pictures off the walls.

"It just shook this place big-time. It was violent. It was really, really violent," Schwartz said.

Earthquakes are graded on a curve that rises sharply upward as the magnitude gets bigger. A magnitude 4 is 10 times bigger than a 3, and a 5 is 10 times the size of a 4. The strongest quake Oklahoma has seen in the modern era was a 5.7 that hit east of Oklahoma City in 2011, knocking down brickwork and causing a handful of injuries; the US Geological Survey has linked that quake to injection wells nearby.

"I wouldn't want to feel a 5, I'll tell you that," Johnston said.

At the supermarket, employees noticed some light shaking from a 4.0 around 12:45 p.m. When the 4.5 hit about half an hour later, the store's security cameras captured Lois Gillette doing what she called her "earthquake dance"— jumping and staggering as the shock arrived.

"I know oil and gas is our economy here, and it is," she said. "We've been tied to oil and gas for 100 years. I know it's important, but I want the earthquakes to quit."

There seems to be an oil well in every other field in north-central Oklahoma. The industry is the bedrock of the state's economy, accounting for one out of every five jobs. And for each gallon of oil that gets pulled out of the ground, 10 gallons or more of saltwater gets drawn up as well.

That water gets separated out and trucked to places like West Perkins Commercial Disposal, northeast of Oklahoma City. The water pours out of the back of a tanker and into a nearby sump. It's then pumped to a set of 25,000-gallon tanks, where any remaining oil floats to the top and gets shunted off to a separate vessel. Then the brine gets shot underground to depths of more than 6,000 feet.

It's been standard practice for decades. But the amount of "produced water" injected underground has doubled in the past 15 years as new technology — horizontal drilling, hydraulic fracturing, more advanced materials — let companies reach pockets of oil and gas they couldn't get to before. In 2013, operations like West Perkins Commercial Disposal pumped about 160 million barrels of wastewater underground each month.

Meanwhile, even though Oklahoma is far from the major earthquake zones of North America, it's crisscrossed with faults deep underground. And as water starts filling in the rock around them, the odds of them slipping go up.

"The problem has lain here for hundreds or thousands of years," said Jeff Andrews, the well's owner. "It's just that right now, we've got something that's irritating it a little bit."

Scientists learned fluid injection can trigger quakes nearly 50 years ago, said Todd Halihan, who teaches hydrogeology and geophysics at Oklahoma State University. But there's still some question about what sets off these oil-patch tremors, and that's a debate with big implications for the state's economy, Halihan told VICE News.

"You're done if there's some volume that's reached and you can't go past it. But if it's a rate issue, you could spread out and slow down," said Halihan, who sits on a state commission studying the problem.

After years of complaints and several scientific studies, the state officials started to take steps to curtail wastewater injections near quake sites in 2013. Those efforts picked up speed in April, when the Oklahoma Geological Survey formally concluded that the quakes were "very unlikely" to be natural.

There are about 3,200 wells like Andrews' operating at any given time in Oklahoma, said Matt Skinner, a spokesman for the Oklahoma Corporations Commission (OCC), which regulates the oil industry. By August, nearly 600 of them were under orders to reduce either their volume or their depth, Skinner told VICE News.

After the Crescent quakes, the agency announced new limits on injection wells in a broad swath north of Oklahoma City, forcing operations in that "area of interest" to reduce their volumes by nearly 40 percent; three wells near the epicenters of those quakes have been shut down—voluntarily, the commissions stresses.

"They have really stepped up in the last several months," Angela Spotts, an anti-fracking activist in Stillwater, told VICE News. "But what they started in March should have been started a year-plus ago."

The new restrictions have been met with some grumbling from the operators.

Todd Halihan teaches hydrogeology and geophysics at Oklahoma State University.

Tanks at West Perkins Commercial Disposal store crude oil and saltwater, the byproduct of crude drilling, before being injected into the ground.

Andrews has filled the bottom 600 feet of his well with cement, plugging it back from about 6,900 feet to just under 6,300. He's sending records of his injected volumes to the OCC every week. But he says his small operation is being unjustly lumped in with more likely suspects.

"A guy that's sitting over here, that's injecting 3,000 barrels a day at 200 pounds of pressure, he can't be as guilty as a guy who's injecting 100,000 barrels a day at 3,000 pounds of pressure," Andrews said. The solution, he says, is to force the wells to spread out, dispersing the fluid.

Jeremy Boak, the director of the Oklahoma Geological Survey, told VICE News that the restrictions aren't likely to reduce the number of quakes immediately.

"I think everybody expects it took four or five years of very high injection rates to get to this level," Boak said. "So they have generally thought that if there's a response that's actually having an effect, it could take a number of months to show results."

Meanwhile, as the OCC faces a growing problem, state lawmakers have cut the agency's regulatory budget by about 10 percent. The OCC received a $200,000 grant to support research into the link between injection wells and earthquakes this year — but that's swamped by the $1.3 million it lost in the appropriations process.

Halihan said he'd like to take advantage of the current slump in the oil patch to hire an unused rig and drill some test wells.

"And yep, that costs a couple million bucks, but there's rigs sitting around," he said. But instead, he said, "The response is, 'Well, if we cut their budget, it should get better.' "

Representatives of Oklahoma's two largest oil industry groups, the Oklahoma Oil and Gas Association and the Oklahoma Independent Petroleum Association, did not respond to requests for comment. But industry officials have said previously that there's a history of natural seismic activity, injection wells have been operating safely since the 1930s, and injection volumes were higher in the 1980s than today.

In imposing the latest restrictions, however, OCC Vice Chairwoman Dana Murphy said her agency considers the question settled.

"There was a time when the scientific, legal, policy and other concerns related to this issue had to first be carefully researched and debated in order to provide a valid framework for such action," Murphy said. "That time is over."

Spotts said that time could have arrived earlier if it weren't for the outsized influence the oil industry holds over Oklahoma officials.

"Four out of five of us are not connected to the industry, and our homes and lives aren't any less valuable," she said.

Skinner said the state took "a reasoned, scientifically justified approach" to the problem, but plans to conduct a lessons-learned review later.

"Am I going to say that everything we did over the last three years was perfect? Obviously, I'm not going to say that," he told VICE News. But he added, "Right now, we find ourselves obviously dealing with a very, very serious problem, and that's what we're concentrating on."

The week this story was reported, the Oklahoma Geological Survey recorded more than a dozen earthquakes of at least magnitude 3. Point your mouse at a dot for details.

Often, the quakes pass with only a vague rocking. Many go unnoticed in town, their energy swallowed up by the vast prairie.

"We get some of the earthquakes here, and the glasses shake. That's how we know," said Chloe Garrett, a waitress at a truck stop in Stillwater. They seem to be getting longer, but they still rank low on the list of what rattles Oklahomans, she said.

"A tornado's more scary for us," Garrett told VICE News. .

But little quakes can add up to big problems for homeowners like Lisa Griggs.

Griggs has a small farm in Guthrie, just up Interstate 35 from Oklahoma City. Quakes were pretty frequent there by November 2014, when she underwent surgery for intestinal cancer.

In the weeks after that, a friend who was helping take care of her noticed the guest-room toilet was leaking. She had a plumber check it out, thinking she'd replace both of her home's commodes with low-flow models.

"He went into the main bathroom and pulled that toilet out and said, 'You know what, these floors are so damaged, I can't replace it. I can't get it to seal. The floors are just too bad,' " Griggs told VICE News.

She'd already noticed small things — cracks in her exterior brickwork and kitchen tile, bouncy spots in her hardwood floor, cabinets pulling away from the walls. Around Christmas, she started noticing cracks in the concrete of her front porch. She started keeping a log in January, recording more than 70 quakes in the first six months of 2015.

"It's a cumulative effect over a long period of time," Griggs said.

Her insurance company estimated the damage to her home at nearly $75,000. It's now gutted and being rebuilt. Fortunately, her insurance not only covered earthquake damage, it's also paying for the Oklahoma City rental house where she's staying for now with her two dogs and a cat. It's even paying for someone to take care of her goats while she's away.

She's one of the lucky ones. In 2014, homeowners filed 120 claims for earthquake damage, Oklahoma Insurance Department spokeswoman Kelly Collins told VICE News. Only 17 of those were approved, for a total payout of $20,039. Many people don't get quake insurance, since they tend to have high deductibles, and many companies don't cover man-made events.

"It's probably going to be too hard to prove that it's earthquake damage, and you have to have major stuff to collect," said Sharon Lancaster, a friend who was helping Griggs change her bandages. "I don't know how anybody gets it any more, because they're all the time."

Lisa Griggs in the backyard of a rental home in Oklahoma City, OK after her home in Guthrie, OK was severely damaged in an earthquake.

A road sign wars drivers that there is a seismic crew near the road conducting tests at drill site.

As the number of quakes has skyrocketed, so has the number of bigger quakes. There was only one quake in the 4 range in 2012; there were 15 in 2014, and 2015 has already passed that mark. Statistically, for every 10 quakes in the 4 range, there's a 5. And the current chance of a 6 — a strong quake that can inflict extensive damage or injuries in populated areas — in the next year are 1 in 100, Halihan said.

Those odds, coupled with a recent ruling by the Oklahoma Supreme Court, are starting to raise eyebrows on Wall Street.

"The earthquake trend has and will continue to have sharp economic consequences for home and business owners, mortgage lenders, insurance companies, and investors exposed to real estate in earthquake affected areas," the bond rating agency Standard and Poors noted shortly after the Crescent outbreak.

The last major US earthquake was the Northridge quake in California, near Los Angeles. It was a 6.7 that killed 60 people and cost $44 billion in 1994, S&P reported.

"It can take a long time for subterranean pressures to build to a breaking point. So, too, for credit risks tied to earthquakes," the ratings agency stated. "In our view, however, the moment to prepare for such events has already arrived."

And Spotts told VICE News that report "is rattling everybody, because they're starting to realize it's going to impact the whole state."

Oklahoma already gets poor marks for the condition of its bridges, levees and roads. In 2013, the American Society of Civil Engineers gave the state's infrastructure a collective grade of C-minus.

"You can't take something that's inferior and keep beating the shit out of it," she said.

The size and orientation of Oklahoma's known faults could make it less likely for a major quake to happen, Boak said. But he said some faults haven't been found until after they go off.

"We have mapped as many faults as we can find," Boak said. "But many of the earthquakes look like they're happening in an area where that fault map is fairly sparse."

Meanwhile, at the end of June, there was a legal earthquake: Oklahoma's highest court ruled that people could sue oil companies over the earthquakes.

Sandra Ladra suffered leg injuries when the rock facing of her chimney collapsed in the 5.7 quake that hit the town of Prague in 2011. She's suing two companies that ran injection wells in the area, arguing they were negligently conducting "ultrahazardous activities." The oil companies argued that the proper place for her claims was the OCC, but the state Supreme Court found Ladra should get her day in court.

But there's a difference between knowing how the quakes are triggered and proving which well set it off — and it may not be hard for lawyers to take advantage of that gap.

"You could say that 'I'm injecting, but there's a lot of reasons it's not all me, or not me at all,' " Halihan said.

A Stanford University study published in June found that the quakes may occur miles away from an injection well and long after its use. Even if all of those wells were shut down immediately, the quakes could continue for months or years, it found.

"If I was paid by a couple of shifty lawyers to say one of those options, I could set up an argument using peer-reviewed literature on any of those and try to push that as the reasonable case," Halihan said. Without more in-depth data, "It's going to be a fuzzy case."

And back in Crescent, Johnston said the July 27 shakes cost him about $500. But that figure could have been $50,000 if a whole shelf had toppled — and he doesn't have quake insurance.

"Something like this could kill a town," he said. As he sees it, there are three things a small town needs to survive: A grocery store, a bank and a post office. "Once you lose any one of those three, you're in trouble."

Follow Matt Smith on Twitter: @mattsmithatl

All photos by Sebastian Meyer for VICE News.