Element concentrations and stable isotope values of groundwater from a well at Hafralaekur in northern Iceland.

Groundwater samples have been collected on a weekly basis from a 100 meter deep well at Hafralaekur in northern Iceland since 2008. These samples were collected in low-density-polyethylene bottles. They were filtered and samples intended for element concentration analysis were acidified with ultrapure HNO3. The groundwater samples have then been analyzed for element concentrations (Ca, K, Na, Si), using Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES), and for for stable isotope values (O, H), using Cavity ring down spectroscopy (CRDS) for the purpose of studying changes of groundwater chemistry before and after earthquakes.