What is "Exploration Phenomenology"?
Since the World War II Manhattan Project, Los Alamos National Laboratory (LANL) scientists have been leaders in creating models of the shock and stress waves generated by explosions and earthquakes. Scientists rely on LANL's enormous computing capability to develop these models. They then can compare their computer simulations with results from actual explosions captured with sophisticated field equipment. As the following examples show, the close correlations have given these researchers a high level of confidence in their numerical modeling methodology. This predictive capability is used to understand the physical basis of explosions and earthquakes, to assist experimenters in planning their work, and to interpret data from seismograms and other monitoring devices now used throughout the world.
An Example: Simulation of the US Department of Energy Non-Proliferation Experiment
One example of Los Alamos modeling capabilities is given by the simulation of the DOE Non-Proliferation Experiment, an underground chemical explosion conducted at the Nevada Test Site (NTS). The NPE source consisted of 1.29x106 kg with the approximate energy of 1.1 kilotons. A cross-section of the modeled geology of the NPE site reveals the highly layered nature of that location. Critical to any numerical simulation is "ground truthing" calculations to data.
Simulation of Near-Regional Seismograms
Modeling the geologic response to explosion sources covers the range from within the explosion source itself, through the (nonlinear) near-source region, out to regional seismic distances in the (linear) elastic region. One example of the computational capability at these regions is the investigation of subsurface structure near the DIVIDER underground nuclear test at the Nevada Test Site.
Support of Experimental Planning
The results of numerical modeling assist Los Alamos field geophysicists in the planning of experimental activities by providing estimates of peak accelerations, velocities, and stresses. Outcomes of a proposed Los Alamos experiment that would consist of a 1x80 ft, 3300 lb. cylinder of ANFO detonated at an Indiana coal mine are calculated based on "best guess" estimates of material properties. These calculations are used in concert with phenomenological scaling curves to guide experimentalists in the placement of gages in the field.
For more information, please contact Wendee Brunish.