Old faithful geyser performance 1870 through 1966

SummaryThe performance of Old Faithful has been remarkably stable for the past 100 years. Rainfall and earthquakes have had little influence on its eruption cycle, although the Hebgen Lake Earthquake of 1959 caused a sudden lengthening of the long interval between eruptions. The principle change has been the gradual developmnt of a bimodal character to the frequency distribution curve for the intervals between eruptions.