Investigating geothermally-heated ground at Pilgrim Hot Springs, Alaska using remote sensing observations of anomalous snow-melt and in-situ shallow temperature measurements
Abstract
In quantifying the near-surface heat loss from a geothermal system it is important to consider the heat flux associated with areas of thermally anomalous ground. This may account for a larger fraction of the total heat loss than is associated with more discrete geothermal surface features such as hot springs, geysers or fumaroles. In cold or snow-covered environments geothermal ground heating can lead to the development of snow-free areas due to the lack of snow-pack development or premature ablation. There is potential to use this phenomenon as a tool to map and quantify the heat flux associated with geothermally-heated ground in cold environments. Preliminary results of investigations of thermally anomalous ground at Pilgrim Hot Springs, Alaska using remote sensing observations of snow-melt anomalies and in-situ measurements of shallow subsurface temperatures are presented. As part of this work a time series of ASTER satellite and airborne imagery was used to delineate the changing extents of snow-free areas during the winter to spring transition period over a number of years. By tracking the development and expansion of anomalous snow-free areas we aimed to map the magnitude and extent of the geothermal heat flux (GHF) based upon the assumption that the perimeters of snow-free areas represent pseudo-subsurface temperature/GHF contours. In-situ measurements of shallow ground temperature were used to calculate GHF values that were then assigned to the different snow-free perimeters. The GHF contours were interpolated to produce a continuous map of GHF for the study site that was compared against a second set of validation GHF measurements. The interpolated GHF map was used to derive the total heat flux supporting areas of geothermally-heated ground that produce snow-melt anomalies. This was compared against maps of GHF and total heat flux estimates produced from ~20 - 40m depth Geoprobe holes.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2012
- Bibcode:
- 2012AGUFM.V13A2808H
- Keywords:
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- 0933 EXPLORATION GEOPHYSICS / Remote sensing;
- 1926 INFORMATICS / Geospatial;
- 8424 VOLCANOLOGY / Hydrothermal systems