Explosion Source Characteristics in Frozen and Unfrozen Rock

• Main Authors: Bonner, Jessie L., Leidig, Mark R., Murphy, Katherine, Dougherty, Sara L., Martin, Randolph J.
• Other Authors: WESTON GEOPHYSICAL CORP WESTBOROUGH MA
• Format: Text
• Language: English
• Published: 2008
• Subjects: Geology; Geochemistry and Mineralogy; Explosions; *EXPLOSIONS; *ROCK; SEISMOMETERS; FREEZING; ICE; SEISMOLOGY; PERMAFROST; ALASKA; CRACKS; SATURATION; FRE(FROZEN ROCK EXPERIMENT); PE62601F; WUAFRL1010SMA1; Ice; permafrost; Alaska
• Online Access: http://www.dtic.mil/docs/citations/ADA487636; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA487636

The Frozen Rock Experiment (FRE) was conducted in central Alaska in August 2006 to provide empirical data on seismically-estimated yield from explosions in frozen rock. Laboratory studies have demonstrated that frozen rock is significantly stronger than unfrozen rock, and it has been hypothesized that this increased strength, due to ice in the pores and cracks, can alter seismic yield. Central Alaska has abrupt lateral boundaries in discontinuous permafrost, and we detonated 3 shots in frozen, saturated rock and 3 shots nearby in unfrozen, dry rock ranging in size from 200 to 350 Ibs. Approximately 125 accelerometers and seismometers were deployed specifically for this experiment at distances of 10 m to over 20 km. During the past year, we have conducted various studies (moment tensors, magnitudes, etc.) to characterize the explosions in frozen and unfrozen rock. The original document contains color images. All DTIC reproductions will be in black and white. Prepared in cooperation with New England Rsearch, Inc. Pub. in Proceedings of the Monitoring Research Review - Ground-Based Nuclear Explosion Monitoring Technologies (30th), v1 p563-572 Sep 2008. Presented at the Monitoring Research Review - Ground-Based Nuclear Explosion Monitoring Technologies (30th) held in Portsmouth, VA on 25 Sep 2008.