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A case study of resistivity and self‐potential signatures of hydrothermal instabilities, Inferno Crater Lake, Waimangu, New Zealand
Author(s) -
Legaz A.,
Vandemeulebrouck J.,
Revil A.,
Kemna A.,
Hurst A. W.,
Reeves R.,
Papasin R.
Publication year - 2009
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 - 10.1029/2009gl037573
Subject(s) - electrical resistivity and conductivity , impact crater , geology , hydrothermal circulation , crater lake , volume (thermodynamics) , electrical conductor , mineralogy , geophysics , geomorphology , materials science , paleontology , physics , quantum mechanics , astronomy , composite material
Inferno Crater Lake, Waimangu, one of the largest hot springs in New Zealand, displays vigorous cyclic behavior in lake level and temperature. It provides a natural small‐scale laboratory for investigating the geo‐electrical signature of fluid flows. We measured self‐potential and electrical resistivity to see whether the huge variations of fluid volume, approximately 60,000 m 3 during a mean cycle period of 40 days, could be detected. Electrical resistivity measurements revealed spectacular changes over time, with the medium becoming more conductive as the lake receded. This result is consistent with analog models, where the vapor phase is replaced by liquid at recession. The self‐potential survey did not detect temporal changes related to fluid movements. This can be explained by the pH of the pore water (∼2.3), which is close to the point of zero charge of silica.