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GEOPHYSICAL RESEARCH LETTERS,
VOL. 30, NO. 22,
2173,
doi:10.1029/2003GL018676,
2003
Groundwater level changes in a deep well in response to a magma intrusion event on Kilauea Volcano, Hawai'i
Shaul Hurwitz
U.S. Geological Survey, Menlo Park, California, USA
Malcolm J. S. Johnston
U.S. Geological Survey, Menlo Park, California, USA
Abstract
On May 21, 2001, an abrupt inflation of Kilauea Volcano's summit induced a rapid and large increase in compressional strain,
with a maximum of 2 μstrain recorded by a borehole dilatometer. Water level (pressure) simultaneously dropped by 6 cm. This
mode of water level change (drop) is in contrast to that expected for compressional strain from poroelastic theory, and therefore
it is proposed that the stress applied by the intrusion has caused opening of fractures or interflows that drained water out
of the well. Upon relaxation of the stress recorded by the dilatometer, water levels have recovered at a similar rate. The
proposed model has implications for the analysis of ground surface deformation and for mechanisms that trigger phreatomagmatic
eruptions.
Received 20
September
2003;
accepted 28
October
2003;
published 28
November
2003.
Index Terms: 5104 Physical Properties of Rocks: Fracture and flow; 8045 Structural Geology: Role of fluids; 8494 Volcanology: Instruments and techniques; 8424 Volcanology: Hydrothermal systems (8135); 8160 Tectonophysics: Rheology—general.
Read Full Article (file size: 268076 bytes) Cited by
Citation: Hurwitz, S., and M. J. S. Johnston
(2003),
Groundwater level changes in a deep well in response to a magma intrusion event on Kilauea Volcano, Hawai'i,
Geophys. Res. Lett.,
30(22),
2173,
doi:10.1029/2003GL018676.
This paper is not subject to U.S. copyright. Published in 2003 by the
American Geophysical Union.
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