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 in the Mediterranean areas, all very famous for their agriculture and plastic greenhouses. They are just sucking all the water out of the aquifers, drying them out," he told The Associated Press in a telephone interview. "From Lorca to (the regional capital of) Murcia you can find a very depleted water level."
De las Doblas said it was "no coincidence that all the aftershocks were located on the exact position of maximum depletion."
"The reason is clearly related to the farming, it's like a sponge you drain the water from; the weight of the rocks makes the terrain subside and any small variation near a very active fault like the Alhama de Murcia may be the straw that breaks the camel*s back, which is what happened," he said.
He said excess water extraction was common in Spain.
"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."
Lorca town hall environment chief Melchor Morales said the problem dates back to the 1960s when the region opted to step up its agriculture production and when underground water was considered private property. A 1986 law has reduced the amount of well pumping, he said.
Not everyone agreed with the conclusion of the study, which was published online Sunday in Nature Geoscience.