GUTHRIE, OKLAHOMA — Inside the small U-Haul rental office in Guthrie, Oklahoma, Tami Boxley routinely deals with something that once was rare: the rattling, booming roll of the earth.

In the last week alone, residents of Guthrie, pop. 10,191, have felt five quakes rock the town a half hour’s drive from Oklahoma City.

The most recent rippled through Friday after lunchtime, duly recorded on the “QuakeWatch” application many residents have loaded onto their smartphones. The local newspaper runs a weekly column updating details of the latest quakes.

“It feels like the earth is opening up and you are falling,” said Boxley. “It’s scary.”

Since January, Oklahoma has had 292 earthquakes that register a magnitude 3.0 or larger, more than any other state in the continental United States. That’s nearly triple the 109 last year. Through 2008, Oklahoma averaged less than two a year.[http://link.reuters.com/vyg62w]

The unprecedented earthquake activity has put Oklahoma in the center of an emerging debate over whether the disposal of wastewater from oil and gas production triggers earthquakes. It has prompted enactment of broad new rules that go into effect Sept. 12.

“The houses are bouncing. It is frightening,” said Matt Skinner, spokesman for the Oklahoma Corporations Commission, which regulates oil and gas work […]