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U.S. Department of Energy
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Tensor controlled-source audiomagnetotelluric survey over the Sulphur Springs thermal area, Valles Caldera

Technical Report ·
DOI:https://doi.org/10.2172/5493785· OSTI ID:5493785

The extensive tensor CSAMT survey of the Sulphur Springs geothermal area, Valles Caldera, New Mexico, consists of 45 high-quality soundings acquired in continuous-profiling mode and has been funded in support of CSDP drillholes VC-2A and VC-2B. Two independent transmitter bipoles were energized for tensor measurements using a 30 KW generator placed approximately 13 km south of the VC-2B wellhead. These current bipoles gave source fields over the receiver sites which were substantially independent in polarization and provided well-resolved tensor elements. The surroundings in the Sulphur Springs area were arranged in four profiles to cross major structural features. At each receiver, two orthogonal electric and three orthogonal magnetic field components were acquired in accordance with tensor principles. Derivation of model resistivity cross sections from our data and their correlation with structure and geochemistry are principal components of the OBES award. However, Sulphur Springs also can serve as a natural testbed of traditional assumptions and methods of CSAMT with quantification through rigorous model analysis. Issues here include stability and accuracy of scalar versus tensor estimates, theoretical versus observed field patterns over the survey area, and controls on near-field effects using CSAMT and natural field data both inside and outside the caldera.

Research Organization:
Utah Univ. Research Inst., Salt Lake City, UT (United States). Earth Science Lab.
Sponsoring Organization:
DOE; USDOE, Washington, DC (United States)
DOE Contract Number:
FG02-89ER14083
OSTI ID:
5493785
Report Number(s):
DOE/ER/14083-1; ESL--91023-TR; ON: DE92010950
Country of Publication:
United States
Language:
English