HR: 1340h
AN: ED33A-0764    [Abstracts]
TI: It's a Blast! Results from a Teacher-Researcher Collaboration to Study Mining Explosions in Indiana
AU: * Combs, W B
EM: wcombs@chs.cville.k12.in.us
AF: Crawfordsville High School, One Athenian Dr, Crawfordsville, IN 47933 United States
AU: Shannon, E
EM: ewashannon@hotmail.com
AF: Crown Point High School, 401 W. Joliet St, Crown Point, IN 46307 United States
AU: Kelly, M
EM: mrkelly@sigecom.net
AF: Harrison High School, 211Fielding Rd., Evansville, IN 47715 United States
AU: Hamburger, M
EM: hamburg@indiana.edu
AF: Indiana University, Dept. of Geol. Sci 1001 East 10th Street, Bloomington, IN 47405 United States
AU: Gary, P
EM: pavlis@indiana.edu
AF: Indiana University, Dept. of Geol. Sci 1001 East 10th Street, Bloomington, IN 47405 United States
AB: The most common signals recorded by the PEPP network in Indiana are mining explosions from surface coal mines and aggregate quarry operations. We examined recording from 30 events from west-central Indiana with known locations determined through previous work by a high school student involved in the program. We also obtained more precise ground truth from a mine near Evansville including one shot with near-field recordings. We examined data from these explosions in three independent, but related projects. One study used high-frequency Rayleigh waves to develop group velocity curves that have proven useful for location of mining explosions in the region. We measured arrival times of surface waves observed with narrow band filters centered at 0.6, 0.8, 1.0, and 1.2 Hz. These data were inverted using two different procedures that yielded consistent results. We measured group velocities of 2.40, 2.28, 1.99, and 1.83 km/s, respectively. The second study focused on velocities from the mine in Evansville with a known origin time. These results suggested a possible bias in the origin time computed from the surface wave group velocity measurements due to timing of the peak amplitude instead of the signal onset. The third study examined the amplitudes from the west-central Indiana data in order to determine the amplitude decay characteristics of these events with the aim of using the results for yield estimation of explosions in the region. We measured best-fit amplitude decay curves for the same four frequency bands used for group velocity estimation. The decay rates increased strongly with increasing frequency, which is probably due to stronger dispersion in the higher frequency bands. The best-fit curves allowed us to estimate a pseudo-magnitude for each frequency band. We found a poor correlation of the pseudo-magnitudes to the known yields of these explosions, suggesting that amplitudes are being influenced strongly by details of blasting practice in different mines. These projects can provide the foundation for future collaborative research between teachers and high school students working on data from this network.
DE: 0805 Elementary and secondary education
DE: 0830 Teacher training
DE: 0850 Geoscience education research
SC: Education and Human Resourcese [ED]
MN: 2004 AGU Fall Meeting