[Geysers] Grand interval is changing?

[Gordon Bower]

Grand has had huge changes in its interval in the past -- not down to 5 hours, but swings between twice a day and twice a week (and at least one significant dormancy.) It has stayed between say 8 and 13 hour averages almost all of the last 20 years though.


> would love to see like a  
> chart of the averages over the years. 

Such a chart exists, but it's in two pieces: you can get the recent history off the GOSA web site, and the "ancient" history in the late John Rinehart's book "Geysers and Geothermal Energy" (or in a couple of his journal articles.)

He was a believer that the 18.6-year tidal cycle affected Grand and Riverside, and claimed to have inspected the old of Grand data and seen it swing back and forth three times. There is a chart in his book showing average interval of both geysers for a period like 1900-1965 or 1970. He published a prediction of a big increase in intervals a few years back before he died - which didnt happen - but it may be time for another big decrease according to his theory.

GRB