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| Credit: John Townend |
Townend et al. recently published measurements made in the Deep Fault Drilling Project DFDP-2B borehole and studied the hydraulic properties of the Alpine fault and the damage zone surrounding it. Using downhole logging equipment and surface measurements, the scientists measured temperature, pressure, and a broad range of other geophysical parameters along the length of the borehole.
The science team discovered that the rocks surrounding the Alpine Fault are much hotter than anticipated and are extensively fractured. Mud level data revealed that the hanging wall portion of the fault—the upthrown (Pacific) side of the fault—contains an active hydraulic system in some areas. Scientists observed that mud levels equilibrated rapidly during the drilling, showing that some fractures in the rock surrounding the fault can transmit large volumes of water in a matter of hours.
Petrophysical, Geochemical, and Hydrological Evidence for Extensive Fracture-Mediated Fluid and Heat Transport in the Alpine Fault's Hanging-Wall Damage Zone, by John Townend, et al. Geochemistry, Geophysics, and Geosystems, https://doi:10.1002/2017GC007202, Volume 18, Issue 12, December 2017
From the Global Geothermal News archives:
- Thursday, December 17, 2015 - New Zealand: Drilling Project Encounters a Very High Geothermal Gradient