Faculty Advisor

Tepper, Jeffrey

Area of Study

Science and Mathematics

Publication Date

Summer 2016


The state of Washington contains 98 low temperature (surface temperatures between ~ 20 - 50 oC) geothermal springs, which are powered by the convective circulation of groundwater that is heated by the natural heat of the Earth. These systems operate in a cycle that begins when precipitation percolates downward into the subsurface and comes in contact with a heat source. Subsequently the heated water returns to the surface, in most cases, having interacted chemically with rocks in the reservoir and/or along its ascent path. Surveys done by the USGS between the 1970s – early 1990s show there is significant chemical variation amongst these thermal springs. The objective of this research is to investigate the origins of this chemical diversity. Using water chemistry and isotopic data, the study has been able to suggest the following:

  1. Estimated subsurface water temperatures are indicative of low-temperature geothermal systems
  2. The dominant component of spring waters is meteoric in origin
  3. The springs are most likely representative of outflow-type structures
  4. Geothermal systems in Cascade Arc are volcanically hosted while systems in the Olympic Peninsula are presumed to be fault-controlled convective cells


University of Puget Sound

Included in

Geochemistry Commons