Preliminary results from an isotope hydrology study of the Kilauea Volcano area, Hawaii

Deuterium (D) content of groundwater and precipitation, and tritium content of selected groundwater samples are used to infer flowpaths for groundwater in the Kilauea Volcano area. The spatial distribution of calculated recharge elevations and residence times for groundwater samples tends to support the idea that Kilauea's rift zones comprise leaky boundaries within the regional groundwater flow system, partly isolating the groundwater in the area bounded by the rift zones and the Pacific Ocean. The southwest rift zone also appears to act as a conduit for groundwater recharged at relatively high elevation. The relation between precipitation ??D values and elevation differs between areas receiving frequent rainfall and areas where most rainfall occurs during storm events.