To hunting, shooting and fishing, a rugged Oklahoman named Mark Crismon has added one more hobby: seismography. Festooned on the walls of his backyard shed are antlers and bushy tails that once belonged to deer he has killed over the years. But these days his mind is on earthquakes.
Mr Crismon’s wares are arranged around a laptop connected to a seismometer from a local university, which is buried 3ft under his garden. It carries a non-stop feed of wavy lines recording the amplitude of ground vibrations across the state. At least once an hour, a sudden burst of spikes signals a tremor that someone will have felt — each one representing an unexpected new threat to the US’s oil and gas revolution.
The energy market has been transformed by surging production of “tight” oil and gas, which horizontal drilling and hydraulic fracturing (or fracking) are freeing from shale and other rock formations. With US oil output close to 10m barrels a day — the all-time high it hit in 1970 — America has cut its dependence on Middle Eastern imports, created thousands of jobs and produced an oil glut that has helped to lower the global crude price.
But Mr Crismon — and scientists who have studied the issue — say it is not all good news. They blame the shale boom for triggering a spate of earthquakes that are shredding nerves and damaging homes. “It just tears everything. I got cracks everywhere,” says Mr Crismon, who compares the state to a war zone. “Instead of having bombs you got earthquakes.”
Quakes were rare in Oklahoma until 2009. But last year the state had a record 584 with a magnitude of 3.0 or over — more than in the previous 30 years combined, according to the Oklahoma Geological Survey. This has pushed the state past California to become the most rattled part of the continental US. No-one has been killed, but the largest recent quake, a magnitude 5.6 jolt in the tiny town of Prague in 2011, injured two people and destroyed 14 homes.
The shale boom has been helped by a drill-first-ask-questions-later approach permitted by some US states. But the quakes could mark a turning point. Bob Jackman, a petroleum geologist and former oil and gas operator, says they are a “warning flag” that carelessness will catch up with oil companies. “It’s a caution to the fossil fuel industry that you must weigh other considerations.”