Earth Tremors Generated by Old Faithful Geyser.
Several types of earth tremors that could be associated with the eruption cycle of Old Faithful Geyser were registered by a seismograph placed a few meters from the geyser's orifice. Each tremor type was indicative of a specific geyser action. A totally unexpected result was an observed bimodal distribution in frequency of the interval between eruptions.
Rinehart
J S
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