Understanding how source parameters such as material properties, topography, depth, stress, and yield affect seismic (i.e., ground displacement), acoustic, thermal, and radiation signal generation from explosions is important for nuclear explosion monitoring. Compared with other geophysical research, explosion dynamics studies are sparse with respect to varied source parameters and how the corresponding shock wavefields interact with the surrounding environment (e.g., fracture/damage, topography, structures). There have been a limited number of modeling studies that investigate the effects of varied source generation on local and regional seismic waveforms (e.g. Stevens and O’Brien, 2018). Elucidating such cause-and-effect relationships requires sophisticated modeling techniques including time- and space- dependent approaches such as finite element and/or finite difference methods. Some recent studies have made significant progress on numerical modeling efforts of field experimental observations (e.g., Ford and Vorobiev, 2020), on incorporating realistic physics, including damage (e.g. Stevens and O’Brien, 2018), fluid dynamics (e.g., Shestakov et al., 2020), and on radiative transport (e.g., Shestakov et al., 2020). With recent increases in computing power and expanding access to high performance computing resources, large-scale parameter space studies are possible and currently developing. However, such modeling studies are still somewhat limited due to specifics within each computer code (e.g., implemented physics, parallelization), and/or the computer architecture utilized. Additionally, integrating observed or known data (e.g., material properties, topography, temperature) into these models can be challenging and time consuming.

Application of advanced numerical models for explosion dynamics is a continuously developing area of research that encompasses, but is not limited to, developing novel modeling techniques, code verification, incorporating known physics of underground/above ground source generation and resultant wave propagation, and large-scale parameter space studies. Numerical modeling skills that could build on these efforts to help fulfill Air Force needs are sought.

Ford, S. R., and Vorobiev, O. Y. (2020). Characterization of Spall in Hard Rock from Observations and Simulations of the Source Physics Experiment Phase I. Bulletin of the Seismological Society of America, 110(2), 596-612.

Stevens, J. L., and O'Brien, M. (2018). 3D nonlinear calculation of the 2017 North Korean nuclear test. Seismological Research Letters, 89(6), 2068-2077.

Shestakov, A., et al. (2020). Challenges in simulating ground interacting nuclear explosions. No. LLNL-JRNL-814197. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States).

key words

Numerical Models; Explosion Source Dynamics; Nuclear Explosion Monitoring; Seismic Waves

Citizenship:  Open to U.S. citizens

Level:  Open to Postdoctoral and Senior applicants

Additional Benefits

Relocation

Awardees who reside more than 50 miles from their host laboratory and remain on tenure for at least six months are eligible for paid relocation to within the vicinity of their host laboratory.

Health insurance

A group health insurance program is available to awardees and their qualifying dependents in the United States.