# E4D Team

## Developers and Users

**Tim C. Johnson **is a computational scientist in subsurface geophysical imaging and interpretation related to complex environmental challenges and energy applications. He pioneered the development of E4D-RT, a real-time, four-dimensional subsurface imaging software that allows scientists to “see” subsurface processes and solutions in real time. Tim earned his Ph.D. in Geophysics at Boise State University.

**Judy Robinson **is a computational scientist with field and numerical modeling experience in geophysical methods. Her work focuses on joint inversion using flow and transport models with electrical resistivity imaging to determine the feasibility of field electrical imaging. She has expertise in analyzing complex resistivity data and in joint physical and geochemical interpretations using corroborating field and lab datasets. She is an E4D developer and maintains the user guide. Judy earned her Ph.D. in Environmental Science at Rutgers University-Newark.

**Piyoosh Jaysaval **is a data scientist with experience in computational geophysics. His research focuses on developing numerical modeling and inversion methods for electromagnetic (EM) and seismic wave propagation in the 2D/3D earth. He has developed several large-scale novel forward modeling and inversion methods, with the main objective of computing results that are more accurate or reducing total modeling and inversion times. Piyoosh earned his Ph.D. in Geophysics at the University of Oslo, Norway.

**Yue Zhu** is a geophysicist whose research interest focuses on numerical modeling and inversion of geophysical data including gravity, magnetic, and electromagnetic fields. She is passionate about the application of computational mathematics in geophysics and development of open-source high performance geophysical inversion codes. Yue earned her Ph.D. in Geophysics at the University of Utah.

**Jeff Burghardt **is an earth scientist focusing on experimental and computational geomechanics. Since joining PNNL in 2016, his/her work has focused primarily on geologic carbon sequestration and enhanced geothermal systems. Jeff's research interests include hydraulic fracturing, induced seismicity, subsurface stress measurement and estimation, chemical/mechanical coupling, rock mechanics, fracture mechanics, and multiphysics modeling. Jeff holds a Ph.D. in Mechanical Engineering at the University of Utah.

**Yilin Fang **is an earth scientist on PNNL's Computational Subsurface Hydrology Team. She earned her Ph.D. in Engineering at Hohai University.

**In addition, these PNNL users support the development of the E4D code:**