I am interested in using thermal processes to understand the Earth. All geologic processes involve the transfer of energy. Heat (energy) and temperature are fundamental to many earth processes, and quantifying the flow of energy and thermal budgets leads to an appreciation and understanding of Earth dynamics. These interests have led me along three paths.

1. Marine Heat and Fluid Flow. See page on U.S. marine heat flow capability. I am trying to understand the curious observation that while midplate hotspot swells exhibit characteristics suggesting a thermal origin including, broad anomalous topography, underplated magmatic material, and young volcanism, at some hotspots, notably Hawaii, excess heat flow has not been observed. At the Hawaiian midplate swell heat flow values across the swell are resolvably lower than values off swell. We hypothesize that fluid flow within the archipelagic apron and upper oceanic crust might be responsible for the lower than expected heat flow values. I am currently seeking to understand the role of seamounts in channeling flow and advecting heat [Hutnak et al., 2008; Harris and McNutt, 2007; Harris and Chapman, 2004; Harris et al., 2004; Fisher et al., 2003]. See also The future of marine heat flow: defining scientific goals and experimental needs for the 21st century, Workshop Report, Fort Douglas, Salt Lake City, Sept. 6-7, 2007.
   
   
   
2. Climate change inferred from borehole temperature-depth profiles. Changes in temperature at the surface propagate slowly downward into the Earth, perturbing the background temperature field. Due to the low thermal diffusivity of rock, temperature perturbations in the uppermost 300 m of the Earth record surface temperature conditions over the last 500 yrs. These subsurface temperature perturbations therefore can be used to reconstruct past ground surface temperature changes not only for this century, but also for the time immediately preceding installation of meteorologic stations, a period of time that is critical to climate change studies. Analyses of borehole temperature logs therefore both complement and extend the meteorological archive of climate data and can usefully be combined with proxy data [Harris and Chapman, 2005].
   
   
3. Temperature and rheology. The thermal state of the lithosphere plays a large role in influencing geodynamics. Boreholes being drilled for strain meter emplacement as part of the NSF funded EarthScope Initiative provide excellent opportunities for new continental heat flow measurements. These measurements, combined with modern geodetic measurements, promise to improve our understanding of continental deformation [Harris et al., 2004; see also Thermal Processes in the Context of EarthScope Workshop Report].

Funded Research:

Installation of a Thermistor Array at ODP Site 642 to Document and Monitor Bottom Water Temperature Variations Through Time - Funded by NSF-IODP

Thermal and Hydrologic Conditions at ODP (Ocean Drilling Program) Hole 642E, Norwegian Margin, Funded by JOI

Drilling Site Survey - The Thermal Environment Associated with Coring in the South Pacific Gyre: Implications for Life in Subseafloor Sediments, Funded by JOI

Workshop on “Thermal processes in the context of EarthScope” - Funded by NSF EarthScope

Geothermics of Climate Change - Funded by NSF-P2C2

Collaborative Research: New Heat Flow Values at PBO Borehole Strain Meter Sites: Implications for deformation, Funded by NSF EarthScope

The Thermal State of 20-25 Ma Lithosphere Subducting at the Costa Rica Margin, Implications for Hydrogeology, Fluxes, and the Seismogenic Zone - Funded by NSF-Margins