Changes in groundwater chemistry before two consecutive earthquakes in Iceland

Handle URI:
http://hdl.handle.net/10754/556727
Title:
Changes in groundwater chemistry before two consecutive earthquakes in Iceland
Authors:
Skelton, Alasdair; Andrén, Margareta; Kristmannsdóttir, Hrefna; Stockmann, Gabrielle; Mörth, Carl-Magnus; Sveinbjörnsdóttir, Árny; Jonsson, Sigurjon ( 0000-0001-5378-7079 ) ; Sturkell, Erik; Guðrúnardóttir, Helga Rakel; Hjartarson, Hreinn; Siegmund, Heike; Kockum, Ingrid
Abstract:
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.
KAUST Department:
Physical Sciences and Engineering (PSE) Division
Citation:
Changes in groundwater chemistry before two consecutive earthquakes in Iceland 2014, 7 (10):752 Nature Geoscience
Publisher:
Springer Nature
Journal:
Nature Geoscience
Issue Date:
21-Sep-2014
DOI:
10.1038/ngeo2250
Type:
Article
ISSN:
1752-0894; 1752-0908
Additional Links:
http://www.nature.com/doifinder/10.1038/ngeo2250
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division

Full metadata record

DC FieldValue Language
dc.contributor.authorSkelton, Alasdairen
dc.contributor.authorAndrén, Margaretaen
dc.contributor.authorKristmannsdóttir, Hrefnaen
dc.contributor.authorStockmann, Gabrielleen
dc.contributor.authorMörth, Carl-Magnusen
dc.contributor.authorSveinbjörnsdóttir, Árnyen
dc.contributor.authorJonsson, Sigurjonen
dc.contributor.authorSturkell, Eriken
dc.contributor.authorGuðrúnardóttir, Helga Rakelen
dc.contributor.authorHjartarson, Hreinnen
dc.contributor.authorSiegmund, Heikeen
dc.contributor.authorKockum, Ingriden
dc.date.accessioned2015-06-10T18:46:14Zen
dc.date.available2015-06-10T18:46:14Zen
dc.date.issued2014-09-21en
dc.identifier.citationChanges in groundwater chemistry before two consecutive earthquakes in Iceland 2014, 7 (10):752 Nature Geoscienceen
dc.identifier.issn1752-0894en
dc.identifier.issn1752-0908en
dc.identifier.doi10.1038/ngeo2250en
dc.identifier.urihttp://hdl.handle.net/10754/556727en
dc.description.abstractGroundwater 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.en
dc.publisherSpringer Natureen
dc.relation.urlhttp://www.nature.com/doifinder/10.1038/ngeo2250en
dc.rightsArchived with thanks to Nature Geoscienceen
dc.titleChanges in groundwater chemistry before two consecutive earthquakes in Icelanden
dc.typeArticleen
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.identifier.journalNature Geoscienceen
dc.eprint.versionPost-printen
dc.contributor.institutionDepartment of Geological Sciences, Stockholm University, 106 91 Stockholm, Swedenen
dc.contributor.institutionUniversity of Akureyri, 600 Akureyri, Icelanden
dc.contributor.institutionInstitute of Earth Sciences, University of Iceland, 101 Reykjavík, Icelanden
dc.contributor.institutionDepartment of Earth Sciences, Gothenburg University, 405 30 Gothenburg, Swedenen
dc.contributor.institutionLandsvirkjun, 103 Reykjavík, Icelanden
dc.contributor.institutionKarolinska Institutet, 171 76 Stockholm, Swedenen
kaust.authorJonsson, Sigurjonen
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