Well, it takes a scientist to get the correct, precise facts...LOL. Regardless of my inaccuracies, it was a very large eruption.
https://volcanoes.usgs.gov/volcanoes/long_valley/I was referring to the 1989 events near Mammoth Lakes, when I was working at Pine Creek mine. There was a swarm of small quakes under Mammoth Mountain in 1980.
The current "Mammoth Scenic Loop" road that avoids the intersection of HWYs 395 and 203, and connects the town with HWY 395 north of Mammoth, was originally known as the "volcano escape route". That road was build after the volcanically related quakes of 1989. That name did not set well with some people who were afraid it would scare tourists and skiers away; it didn't.
Anyway...the point we seem to be making is the region experiences small, frequent earthquakes, and occasional large ones. That is a fact. The question is whether such activity could have damaged the Whitney Portal spring or has it been from structural failure over time? An open investigation might reveal the facts.
Like with the "Mammoth Scenic Loop" road naming, there seems to be a effort to not scare people away from Whitney Portal - quite rightly - but we know the facts regarding human pollution upstream from Whitney Portal.
