An earthquake in Spain was caused by water being sucked out of the ground to feed domestic supplies, a study found
An
earthquake in Spain was caused by water being sucked out of the ground to feed
domestic supplies, a study found. A major earthquake in Spain that killed nine
people was triggered by groundwater extraction, research suggests.
The
magnitude 5.1 tremor struck the historic town of Lorca in south-east Spain in
May last year. In addition to the lives lost, buildings were reduced to rubble,
cars flattened and more than a hundred people injured. Now scientists say they
have evidence that the disaster was man-made - the result of water being sucked
out of the ground to feed domestic supplies. Loss of the water caused stress
changes in the earth's crust along a major faultline, it is believed. The
disturbance was enough to trigger a rupture in the rock, leading to the
earthquake. The findings, published in the journal Nature Geoscience, highlight
the extent to which human activity can influence seismic shocks.
Scientists
led by Dr Pablo Gonzalez, from the University of Western Ontario in Canada,
used satellite data to map the ground deformation caused by the Lorca
earthquake. They then carried out computer simulations of the fault slip. The
results showed a pattern that correlated with stress changes due to loss of
groundwater. Since the 1960s, natural groundwater levels in the region had
reduced by 250 metres. The researchers wrote: "We conclude that the
presented data and modelling results are consistent with a groundwater crustal
unloading process, providing a reasonable explanation for the observed fault
slip pattern.” The findings implied that "anthropogenic activities could
influence how and when earthquakes occur".
In
an accompanying commentary article, Professor Jean-Philippe Avouac, from the
California Institute of Technology in Pasadena, US, wrote: "We should
remain cautious of human-induced stress perturbations. We know how to start
earthquakes, but we are still far from being able to keep them under
control." Professor Peter Styles, from Keele University, said: "This
is a very exciting and stimulating paper. The authors comment on the role which
anthropogenic activity can play in stimulating the response of the crust and
there will no doubt be speculation as to the implications of this for hydraulic
fracturing in the context of shale gas exploration."
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