CONTROLS ON GEYSER PERIODICITY

Geyser eruption frequency is not constant over time and has been shown to vary with small (less-than-or-equal-to 10(-6)) strains induced by seismic events, atmospheric loading, and Earth tides. The geyser syste m is approximated as a permeable conduit of intensely fractured rock s urrounded by a less permeable rock matrix. Numerical simulation of thi s conceptual model yields a set of parameters that controls geyser exi stence and periodicity. Much of the responsiveness to remote seismicit y and other small strains in the Earth can be explained in terms of va riations in permeability and lateral recharge rates.