Top

Spain Earthquake Water Extraction

October 22, 2012 by  

Spain Earthquake Water Extraction, Massive extraction of groundwater helped unleash an earthquake in southeastern Spain last year that killed nine people, injured at least 100 and left thousands homeless, geologists said on Oct. 21. The finding adds a powerful piece of evidence to theories that some earthquakes are human-induced, they said.

Seismologists were surprised by the May 11, 2011 earthquake which happened two kilometers (1.2 miles) northeast of the city of Lorca. The quake struck in the Eastern Betics Shear Zone, one of Spain’s most seismically active regions, where there has been a large number of moderate-to-large temblors over the last 500 years.

But the May event was unusual because it was so devastating and yet so mild — only 5.1 magnitude — in terms of energy release.

Researchers led by Pablo Gonzalez of the University of Western Ontario in Canada probed the mystery.

Reporting in the journal Nature Geoscience, they found that the quake occurred at a very shallow depth, of just three kilometers (1.8 miles), so the shockwave swiftly reached the surface with little to dampen it on the way.

The quake also happened on a complex but dormant fault that ripped open after water had been extensively pumped out of a neighboring aquifer, causing a domino effect of subterranean stresses, they said.

Gonzalez’s team first used ground-radar imaging by the European satellite Envisat to build a map of how terrain around Lorca changed before and after the quake.

The picture confirmed that the event had occurred on the so-called Alhama de Murcia fault, which slipped between five and 15 centimeters (two and six inches).

They then investigated the Alto Guadalentin Basin, an aquifer lying just five kms (three miles) south of the fault, where they found widespread evidence of subterranean subsidence from water extraction.

Report to Team

_________________________________________
Please feel free to send if you have any questions regarding this post , you can contact on

usspost@gmail.com

Disclaimer: The views expressed on this site are that of the authors and not necessarily that of U.S.S.POST.

Comments

Comments are closed.

Bottom