Spanish wells may have spurred earthquake

MADRID -- Farmers drilling ever deeper wells over decades to water their crops probably contributed to a deadly earthquake last year, a new study suggests. The findings may add to concerns about the effects of new energy extraction and waste disposal technologies.

Nine people died and nearly 300 were injured when an unusually shallow magnitude-5.1 quake hit the southern town of Lorca on May 11, 2011. It was the country's worst quake in more than 50 years, causing millions of euros in damage to a region with an already fragile economy.

Using satellite images, scientists from Canada, Italy and Spain found that the quake ruptured a fault running near a basin that had been weakened by 50 years of groundwater extraction in the area.

During this period, the water table dropped by 274 yards as farmers bored ever-deeper wells to help produce the fruit, vegetables and meat that are exported from Lorca to the rest of Europe. In other words, the industry that propped up the local economy in southern Spain may have undermined the very ground on which Lorca is built.

Even without the strain caused by water extraction, a quake was likely to occur at some point, the researchers said. But the extra stress of pumping vast amounts of water from a nearby aquifer may have been enough to trigger a quake at that particular time and place, said lead researcher Pablo J. Gonzalez of the University of Western Ontario, Canada.

Miguel de las Doblas Lavigne, a geologist with Spain's National Natural Science Museum who has worked on the same theory but was not involved in the study, said the Lorca quake was in the cards.

"This has been going on for years . . . They are just sucking all the water out of the aquifers, drying them out," he told The Associated Press. "Everybody digs their own well, they don't care about anything," he said. "I think in Lorca you may find that some 80 percent of wells are illegal."