Groundwater extraction linked to Lorca earthquake

Zeenews Bureau

Washington: The 2011 Lorca earthquake was triggered by excessive extraction of water from a nearby natural underground reservoir, which moved the Earth`s crust, suggests a new study. The moderate earthquake on May 11, 2011, measuring 5.1, had killed nine people and caused significant localised damage in the Region of Murcia, Spain. The study led by Pablo Gonzalez of University of Western Ontario and his team has been published in journal Nature Geoscience. The researchers reckoned that the quake was related to a drop in the level of groundwater in a local aquifer, which can create pressure at the Earth`s surface. Researchers, who used satellite data to test the theory, found that the earthquake was correlated to changes in the Earth`s crust caused by a 250 metre drop in the natural groundwater level over the last five decades due to groundwater extraction. The new findings suggest that human-induced stress on faults like the one near Lorca, known as the Alhama de Murcia Fault, can not only cause an earthquake but also influence how far the fault will slip as a result. "We cannot set up a rule just by studying a single particular case, but the evidence that we have collected in this study could be necessary to expand research in other future events that occur near ... dams, aquifers and melting glaciers, where you have tectonic faults close to these sources," Gonzalez said. In an accompanying article, Jean-Philippe Avouac of California Institute of Technology said the implications could be far-reaching "if ever the effect of human-induced stress perturbations on seismicity is fully understood". "For now, we should remain cautious ... We know how to start earthquakes, but we are still far from being able to keep them under control," Avouac wrote.