Groundwater extraction from agriculture and industry that lowered a nearby aquifer helped spark a quake in Spain last year, a study showed.

LONDON — Groundwater extraction from agriculture and industry that lowered a nearby aquifer helped spark a quake in Spain last year that killed nine people, according to a study published Sunday in Nature Geoscience.

The May 2011 earthquake in Lorca, with a magnitude of 5.1, was triggered after a 820-foot drop in groundwater from pumping since the 1960s ruptured the Earth’s crust along the Alhama de Murcia fault line, according to the study led by Pablo Gonzalez of the University of Western Ontario.

The shallow-depth quake at 1.2 to 2.5 miles in one of the highest seismic risk areas in Spain was “human-induced” by groundwater changes, the study said. The results imply that anthropogenic or man-made activities “could influence how and when earthquakes occur.”

Fracking, or hydraulic fracturing, blasts water mixed with sand and chemicals underground to free trapped hydrocarbons from shale formations. The disposal fracking fluids in deep injection wells sometimes impacts fault lines and has caused small quakes.

The Nature Geoscience study suggests “the stress change induced by water extraction in the Guadalentin basin may have done more than advance the time of an earthquake that would have happened anyway,” Jean-Philippe Avouac from the California Institute of Technology said in an email.