![A computer-generated image with a blue background uses rainbow colors to show where uranium is concentrated underground.](/sites/default/files/styles/thumbnail/public/media/image/E4D%20E4T%20uranium%20screenshot%20hero%209-29-20.jpg?h=08b866d1&itok=Pj2sLvzg)
E4D
A scalable, 3D geophysical modeling and inversion code that uses geophysical measurements to generate images that serve as indicators of subsurface contaminant distributions, injection delivery extent, and dynamic biogeochemical processes. E4D was developed using the PNNL Nuclear Quality Assurance Program (NQAP), an American Society of Mechanical Engineers (ASME) NQA-1 quality program.
![Computer graphic of E4D, showing the colorful three-dimensional image of what's underground.](/sites/default/files/styles/hero_1600x1200/public/media/image/1600x1200_e4d_guide_main_image_hero.jpg?h=08b866d1&itok=ULLUAG1g)
E4D uses electrical resistivity tomography (ERT) measurements to reconstruct time-lapse images of the electrical conductivity of the soil.