Item: Effects of explosives on the mountain snowpack
Title: Effects of explosives on the mountain snowpack
Proceedings: Proceedings of the 1992 International Snow Science Workshop, Breckenridge, Colorado, USA
Authors: Jon Ueland
Abstract: A seismograph was used in a series of tests to measure the shockwaves produced in the snowpack from the detonation of explosives. Two different explosives commonly used in avalanche work were tested. Different shot placements in relation to the snow surface were compared, different types of snowpack were compared, and different size charges were compared. The results showed that a two pound cast Pentolite booster and a 3x8 cartridge of ammonia gelatin dynamite produced almost identical shockwaves. Air blasts were shown to produce slightly larger shockwaves than surface blasts. While buried shots produced much smaller shockwaves than air or surface blasts. A charge detonated 25 cm (10 inches) below the snow surface produced shockwaves of approximately half the amplitude of a surface or air blast. Ground waves were shown to be insignificant, even when charges were detonated on the ground surface. When comparing different snowpacks, the results show that shockwaves penetrate deeper with less attenuation into a harder snowpack, than they do into a softer less dense snowpack. When comparing different size charges, it was shown that doubling the shot size would approximately double the area that was affected by the shockwaves to the same degree.
Keywords: explosives, shockwave, snowpack, avalanche release
Digital Abstract Not Available