Joel Edwards
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Subduction zones + imaging methods


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Vertical Motions offshore Costa Rica

To get at the upper plate's motions, I've been utilizing a technique called seismic sequence stratigraphy within the 3D volume of seismic reflection data. There are a bunch of different flavors to this technique out there, and researchers (and oil companies) really dive into the weeds on this, but essentially the tool is utilized to subdivide offshore strata (layers of sediments) into time.

Mapping unconformities throughout the 3d volume results in unconformable horizons with really neat detail. Check this one out. It's labelled L1 in the above figure and is ~2.5 m.y. See the channel systems to the left? And the big folds to the right? Pretty cool.

Link to paper: pubs.geoscienceworld.org/gsa/geosphere/article/528574/pleistocene-vertical-motions-of-the-costa-rican

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Shallow megathrust morphology

​I've looked at a lot of slicks along onshore faults and it seems like we've stumbled onto them along offshore mega-faults. It turns out the shallow megathrust is corrugated. Spectacular.

Link to paper: www.nature.com/articles/s41561-018-0061-4

Press: www.usgs.gov/center-news/giant-grooves-discovered-earthquake-fault-offshore-costa-rica
Press: news.ucsc.edu/2018/02/megathrust-imaging.html

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Statistical approach to neural network imaging of karst systems in 3D
seismic reflection data

Dan Ebuna wrote up a nice paper detailing our work on imaging karst systems in 3D seismic reflection data in SE Florida. Unknown karst systems can connect deep aquifers used for waste water injection to shallow aquifers used for consumption. He did so by reducing the data dimensionality from training and test inputs into nueral networks using several, user-independent statistical approaches. 

Geothermal

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​Three‑dimensional geologic mapping
to assess geothermal potential
from Nevada and Oregon

Drew Siler wrote up an excellent paper summarizing up his work integrating geologic and geophysical datasets in 3D geothermal potential models, including my thesis work at Neal Hot Springs and from Greg Dering's thesis work at Tuscarora. 

Link to paper: https://geothermal-energy-journal.springeropen.com/articles/10.1186/s40517-018-0117-0

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Structural Controls of the Neal Hot Springs Geothermal System, Malheur County, OR

I spent some time mapping the detailed geology surrounding  Neal Hot Springs and its geothermal system and came up with a left-stepping, west-dipping normal-oblique-slip fault system. Along with decent rock exposure, we had an abundance of well and geophysical data, thanks to collaborations with US Geothermal Inc and Boise State.

Link to thesis: edwards_joel_h_201305_ms.pdf
Link to geologic map: neal_hot_springs_geologic_map_edwards_etal.pdf
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Favorable structural settings for geothermal, Basin and Range

Jim Faulds and company came up with a handful of structural settings that seem to be associated with known geothermal systems in the Basin and Range.

Link to paper: www.atlasgeoinc.com/wp-content/uploads/Faulds_etal_Structural_Settings_GRC_2011.pdf
  • Academic overview
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