Time‐domain electromagnetic soundings in the vicinity of Novarupta, Katmai National Park, Alaska
1991; American Geophysical Union; Volume: 18; Issue: 8 Linguagem: Inglês
10.1029/91gl01759
ISSN1944-8007
AutoresP. Kasameyer, Michael Wilt, William Daily, D. Felske,
Tópico(s)Geochemistry and Geologic Mapping
ResumoA time‐domain electromagnetic survey was conducted near the rhyolite dome Novarupta. We found a continuous (60 to 100 m thick) high‐resistivity surface layer, which represents the unsaturated or unaltered tephra and whose base is probably the water table. This layer is thinnest near fumaroles; the largest thin areas lie under the tephra ring surrounding Novarupta, where the altered zones extend to a depth of more than 100 m. A deeper conductive layer is associated with the top of the underlying sedimentary rocks and is inferred to indicate the depth to the pre‐eruptive surface.
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