HR: 0800h
AN: NS31B-0384    [Abstracts]
TI: Diffusion of electromagnetic eddy currents in unconsolidated alluvium
AU: * Gilliland, E S
EM: elleng@vt.edu
AF: Virginia Tech, Department of Geosciences 4044 Derring Hall (0420), Blacksburg, VA 24061, United States
AU: Weiss, C J
EM: cjweiss@vt.edu
AF: Virginia Tech, Department of Geosciences 4044 Derring Hall (0420), Blacksburg, VA 24061, United States
AB: Recent studies on the diffusive transport of electromagnetic eddy currents in complex geologic materials have invited speculation on novel theoretical frameworks to encapsulate the macroscopic effects of multi-scale geologic complexity. These ideas have been based on a limited amount of data from a restricted suite of geologic environments. To test the veracity of the various diffusion theories proposed in the literature, a new data set is presented here which consists of transient electromagnetic data collected over an alluvial fill aquifer in the Estancia Basin of central New Mexico. Geologic mapping and correlation of historical well-log data show the experiment site to consist of mainly unconsolidated felsic alluvium with intermittent cobble horizons. Analysis of the electromagnetic data in terms of its diagnostic move-out behavior of the source wavelet shows some similarity to previously obtained results in floodplain environments. Further analysis of the data shows that this behavior is dominated by the alluvial texture and not influenced by the underlying basement rock.
DE: 0619 Electromagnetic theory
DE: 0644 Numerical methods
DE: 0925 Magnetic and electrical methods (5109)
DE: 1599 General or miscellaneous
DE: 1835 Hydrogeophysics
SC: Near-Surface Geophysics [NS]
MN: 2007 Fall Meeting