Journal of Volcanology and Geothermal Research, 22 (1984) 59--95 59 Elsevier Science Publishers B.V., Amsterdam -- Printed in the Netherlands
Journal of Volcanology and Geothermal Research, 22 (1984) 59--95 59 Elsevier Science Publishers B.V., Amsterdam -- Printed in The Netherlands SEISMICITY AT OLD FAITHFUL GEYSER: AN ISOLATED SOURCE OF GEOTHERMAL NOISE AND POSSIBLE ANALOGUE OF VOLCANIC SEISMICITY SUSAN WERNER KIEFFER U.S. Geological Survey, 2255 North Gemini Drive, Flagstaff, AZ 86001 (U.S.A.) (Received February 1983; revised and accepted January 19, 1984) ABSTRACT Kieffer, S.W., 1984. Seismicity at Old Faithful Geyser: an isolated source of geothermal noise and possible analogue of volcanic seismicity. In: N. Oskarsson and G. Larsen (Editors), Volcano Monitoring. J. VolcanoI. Geotherm. Res., 22:59 95. Old Faithful Geyser in Yellowstone National Park, U.S.A., is a relatively isolated source of seismic noise and exhibits seismic behavior similar to that observed at many volcanoes, including "bubblequakes" that resemble B-type "earthquakes", harmonic tremor before and during eruptions, and periods of seismic quiet prior to eruptions. Al- though Old Faithful differs from volcanoes in that the conduit is continuously open, that rock-fracturing is not a process responsible for seismicity, and that the erupting fluid is inviscid H20 rather than viscous magma, there are also remarkable similarities in the prob- lems of heat and mass recharge to the system, in the eruption dynamics, and in the seis- micity. Water rises irregularly into the immediate reservoir of Old Faithful as recharge occurs, a fact that suggests that there are two enlarged storage regions: one between 18 and 22 m (the base of the immediate reservoir) and one between about 10 and 12 m depth. Transport of heat from hot water or steam entering at the base of the recharging water column into cooler overlying water occurs by migration of steam bubbles upward and their collapse in the cooler water, and by episodes of convective overturn.
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