Accession Number : ADA017606

Title :   Three-Dimensional Seismic Modeling.

Descriptive Note : Final rept. 1 Mar 74-31 Jul 75,


Personal Author(s) : Erlich,David C.

Report Date : AUG 1975

Pagination or Media Count : 28

Abstract : In this three-dimensional seismic modeling program, a small spherical explosive source was developed which contains about 0.25 g PETN in a 5/16-in sphere, is encapsulated in a 1/16-in-thick plastic shell, and can be detonated by an exploding bridge wire at the center. Tests showed that the source yielded a shock wave that was spherically symmetric to within 2%. Procedures were developed for routing production of these sources. A biaxial prestressing frame was built which is capable of loading blocks of sizes up to 2 x 2 x 1 ft to pressures in excess of 1000 psi on the four 1 x 2 ft faces. Finally, a search was conducted for a seismic modeling material that could be poured or cast in large volumes (1-2 feet on a side) with a high degree of isotropy. A certain grout shows very good promise, but the mixing, pouring, and curing techniques need to be refined for the larger volumes. Syntactic foam shows the highest degree of isotropy but is quite expensive A method that allows reuse of a snytactic foam block, however, will reduce the cost and improve experimental repeatability.

Descriptors :   *Shaped charges, *Seismic waves, Wave propagation, PETN, Encapsulation, Exploding wires, Shock waves, Foam, Grout

Subject Categories : Test Facilities, Equipment and Methods

Distribution Statement : APPROVED FOR PUBLIC RELEASE