Changes in groundwater chemistry before two consecutive earthquakes in Iceland
Type
ArticleAuthors
Skelton, AlasdairAndrén, Margareta
Kristmannsdóttir, Hrefna
Stockmann, Gabrielle
Mörth, Carl-Magnus
Sveinbjörnsdóttir, Árny
Jonsson, Sigurjon

Sturkell, Erik
Guðrúnardóttir, Helga Rakel
Hjartarson, Hreinn
Siegmund, Heike
Kockum, Ingrid
KAUST Department
Crustal Deformation and InSAR GroupEarth Science and Engineering Program
Physical Science and Engineering (PSE) Division
Date
2014-09-21Online Publication Date
2014-09-21Print Publication Date
2014-10Permanent link to this record
http://hdl.handle.net/10754/556727
Metadata
Show full item recordAbstract
Groundwater chemistry has been observed to change before earthquakes and is proposed as a precursor signal. Such changes include variations in radon count rates1, 2, concentrations of dissolved elements3, 4, 5 and stable isotope ratios4, 5. Changes in seismic wave velocities6, water levels in boreholes7, micro-seismicity8 and shear wave splitting9 are also thought to precede earthquakes. Precursor activity has been attributed to expansion of rock volume7, 10, 11. However, most studies of precursory phenomena lack sufficient data to rule out other explanations unrelated to earthquakes12. For example, reproducibility of a precursor signal has seldom been shown and few precursors have been evaluated statistically. Here we analyse the stable isotope ratios and dissolved element concentrations of groundwater taken from a borehole in northern Iceland between 2008 and 2013. We find that the chemistry of the groundwater changed four to six months before two greater than magnitude 5 earthquakes that occurred in October 2012 and April 2013. Statistical analyses indicate that the changes in groundwater chemistry were associated with the earthquakes. We suggest that the changes were caused by crustal dilation associated with stress build-up before each earthquake, which caused different groundwater components to mix. Although the changes we detect are specific for the site in Iceland, we infer that similar processes may be active elsewhere, and that groundwater chemistry is a promising target for future studies on the predictability of earthquakes.Citation
Changes in groundwater chemistry before two consecutive earthquakes in Iceland 2014, 7 (10):752 Nature GeosciencePublisher
Springer NatureJournal
Nature GeoscienceDOI
10.1038/ngeo2250Additional Links
http://www.nature.com/doifinder/10.1038/ngeo2250ae974a485f413a2113503eed53cd6c53
10.1038/ngeo2250