TY - JOUR
T1 - Helium-isotope systematics at Nevado del Ruiz volcano, Colombia
T2 - implications for the volcanic hydrothermal system
AU - Sano, Yuji
AU - Wakita, Hiroshi
AU - Williams, Stanley N.
N1 - Funding Information:
We would like to express our gratitude for the logistical and financial assistance of the following individuals and organizations: P. Medina J., A. Londofio C., N. Garcia P., M.L. Calvache V., L. Rodriguez V., all of the Comit~ de Estudios Vulcanologicos; H.-J. Meyer, E. Parra P., B. Cepeda S. of the Observatorio Vul-canologico de Colombia; J. Ahumada B. of COL-CINENCIAS; UNESCO; the Fuerza Aerea Col-ombiana; National Geographic Magazine; Department of Geology and Geophysics of LSU; Christian Boussert; and N.C. Sturchio. National Science Foundation grants (EAR86-01458; EAR87-202147; INT86-08977; and INT87-14954) to SNW have provided critical sustaining support. Discussion with many of the above people, and W.F. Giggenbach of DSIR, New Zealand and N. Sugiura, G. Ig-arashi and S. Sasaki of Geophysical Institute, University of Tokyo, and S. Aramaki and I. Kaneoka of Earthquake Research Institute, University of Tokyo are also acknowledged. K.M. Kubo of Department of Chemistry, University of Tokyo kindly provided us with the least square method for curve fitting. We also thank an anonymous reviewer of this paper for valuable comments and suggestions, which were enormously useful for improving the paper.
PY - 1990/7/30
Y1 - 1990/7/30
N2 - We have collected 14 water and gas samples from 9 thermal springs and gas vents near Nevado del Ruiz volcano, Colombia. The 3He/4He and 4He/20Ne ratios vary significantly from 0.98 Ratm (where Ratm is the atmospheric 3He/4He ratio of 1.4 × 10-6) to 6.30 Ratm, and from 0.37 to 7.0, respectively. The 3He/4He ratio (corrected for air contamination) decreases with increasing distance from the central crater of the volcano to the sampling site. The trend is very similar to that observed at Ontake volcano, Japan. A hydrodynamic porous-media dispersion model can explain the 3He/4He trend. The temporal variations in the 3He/4He ratio at four sites provide useful information on the apparent velocity of the magmatic fluid flow brought on by a volcanic eruption. The estimated value of several tens m day-1 agrees well with the inferred velocity of flow in Oshima volcano, Japan and is comparable to the largest rate of groundwater movement in a deep sedimentary basin.
AB - We have collected 14 water and gas samples from 9 thermal springs and gas vents near Nevado del Ruiz volcano, Colombia. The 3He/4He and 4He/20Ne ratios vary significantly from 0.98 Ratm (where Ratm is the atmospheric 3He/4He ratio of 1.4 × 10-6) to 6.30 Ratm, and from 0.37 to 7.0, respectively. The 3He/4He ratio (corrected for air contamination) decreases with increasing distance from the central crater of the volcano to the sampling site. The trend is very similar to that observed at Ontake volcano, Japan. A hydrodynamic porous-media dispersion model can explain the 3He/4He trend. The temporal variations in the 3He/4He ratio at four sites provide useful information on the apparent velocity of the magmatic fluid flow brought on by a volcanic eruption. The estimated value of several tens m day-1 agrees well with the inferred velocity of flow in Oshima volcano, Japan and is comparable to the largest rate of groundwater movement in a deep sedimentary basin.
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U2 - 10.1016/0377-0273(90)90068-Q
DO - 10.1016/0377-0273(90)90068-Q
M3 - Article
AN - SCOPUS:0025592463
SN - 0377-0273
VL - 42
SP - 41
EP - 52
JO - Journal of Volcanology and Geothermal Research
JF - Journal of Volcanology and Geothermal Research
IS - 1-2
ER -