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Time‐domain electromagnetic soundings in the vicinity of Novarupta, Katmai National Park, Alaska
Author(s) -
Kasameyer Paul,
Wilt Michael,
Daily William,
Felske Donald
Publication year - 1991
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/91gl01759
Subject(s) - tephra , geology , sedimentary rock , dome (geology) , fumarole , national park , geomorphology , volcano , table (database) , water table , mineralogy , petrology , geochemistry , groundwater , archaeology , geotechnical engineering , computer science , data mining , history
A 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.