Shadowed by St. Helens

Today news reporters are almost happily diverting from COVID-19 to recount another disaster, the eruption of Mt. St. Helens in 1980 on this date. As at least one news account notes, in a way the eruption was a great success for the efforts of the scientists who urged evacuations of areas around the volcano (there is a clear undercurrent of, “are we listening to the scientists today?”). Although there were deaths, there were far fewer than if there had been no evacuated red zone.

But events that started a week later, and went pretty much under the radar for years, provide the flip side to the “confident scientists save people” storyline: it was more “pretty worried scientists deal economic blow to town.” And given where we are in the COVID-19 story, it is worth remembering both the success of St. Helens and the failure(?) that started a week later.

What happened on May 25, 1980, was that three M6 earthquakes rocked the Long Valley area by Mammoth Lakes, California. While this was concerning enough to issue an earthquake hazard watch, earthquakes in California are no big deal, and even though a fourth M6 quake soon followed the watch, folks in the area were used to rolling with these punches.

What followed was a surprise to the scientists working in the area. A resurvey done to examine deformation from the quakes instead found a region of uplift centered just east of Mammoth Lakes within the Long Valley Caldera. That discovery and the documentation by seismologists at the University of Nevada Reno of tremors indicative of fluid movement that were growing shallower and shallower led the USGS in May of 1982 (two years to the day after the original quakes) to issue a notice of potential volcanic hazard (a level below what the scientists working in the area wanted). The feeling was that magma was rising to shallow levels in the crust: an eruption was feasible.

[It is interesting to speculate on a possible connection between St. Helens and Long Valley: we have since learned that magmatic areas are susceptible to triggering from distant earthquakes. Whether something like this happened in 1980 and started the sequence of events leading to the continued unrest in Long Valley remains unknown.]

This alert, coming days before the start of the summer tourist season and with no advance warning to local officials, led to some chaos. St. Helens has erupted two years earlier, so folks were inclined to play it safe and avoid Mammoth. Local businessmen–and thus their Congressman–were furious. As weeks went by with no volcano, pressure grew to rein in the USGS, which locals had renamed the United States Guessing Society. The volcanic warning system after St. Helens was gutted in late 1983.

One day, there will be an eruption near Mammoth Lakes. And the run up to that event most likely will look a lot like what happened in 1980-1982. So the idea of issuing a warning seems justified. But the public’s reaction was overkill in this instance. Given the lives saved at St. Helens, was the USGS so wrong in 1982? Or is this a case of learning how to message uncertainty?

We are staring at a very similar situation right now, though not with quite so easy a target as the USGS. Epidemiologists and public health officials are appalled at some of the restrictions being relaxed; they warn this could lead to a resumption of rapid spread of COVID-19. Ignoring their message is unwise, just as ignoring the warning at St. Helens could well have proven fatal while a different outcome occurred in Long Valley. Does this mean there certainly will be return to rapid growths in deaths and infections? Well, no, for while the state can tell you that you cannot go to work or you cannot gather in large groups, it can’t tell you that you must participate in these activities. If people listen to the health officials and avoid the most risky activities, it could well be that any increase in infection rate will be small. The problem, as at Long Valley in 1982, is that we won’t learn how accurate the warnings are until later, by which time failure to prepare will be disastrous.

And it both cases, what happened after warnings were given would dictate whether disaster would follow or not. In Long Valley, the magma (or hydrothermal fluid, though magma seems a better bet to GG) rose up to a level and slowed its increase. At St. Helens, it kept fueling a shallow magma chamber that eventually erupted. For COVID-19, Georgia was in the spotlight for reopening things despite warnings from public health officials. As of right now, cases are declining and the testing rate is pretty good; does this mean the warning was wrong–that it is in fact safe to ignore the warnings of relevant scientists and officials? Well, restaurant patronage in Georgia was quite low after the governor allowed restaurants to reopen: without a lot of patrons, restaurants might not fuel much of a spike in infections. And so an absence of a massive increase in cases might not mean that all is well and reopening is safe; it might mean that the public behaved sensibly and warded off a worse outcome despite the opportunity to make a mess of things.

The purpose of a warning is to avoid a bad outcome. While in geology we have (at present) no control on volcanoes or earthquakes, the purpose of a warning is to be prepared in case the event comets to pass. For public health, a warning can allow us though our behavior to mitigate or possibly even avoid the undesirable outcomes. It is well to pay close attention to what happens after warnings are made: did the uplift in Long Valley continue, and did seismicity continue to rise to the surface? In Georgia, did the bars and restaurants and massage parlors and gyms all fill up with lots of folks? Or were they pretty empty and behaving pretty responsibly? Warnings don’t fail when the bad thing doesn’t happen; in a sense, that often represents success.

The risk today is that the lag time between bad behavior and disaster is enough to mislead us. Just as it took weeks after strong measures were taken to see the curve of infections flatten and reverse, it will take weeks to see how successful we are at reopening without incurring massive increases in infections. By the time we know we screwed up, we’ll be in a big mess again (hopefully there is enough testing of the population at large to recognize this). But if we were successful, it may well be because of caution and not because of any miscalculation by medical officials. But too there is much unknown about this disease (much as much was unknown at both Long Valley and St. Helens); we might learn of mitigating factors as further study proceeds.

There are no perfect warnings. Lots of people protested against the closure of the Red Zone at St. Helens. They were clearly wrong. Lots of people are protesting the restrictive orders in many states (though GG thinks more people have died from COVID-19 than have engaged in protests). Will they be equally wrong? We might never know for sure, because unlike the volcano, our fate rests in large part in our collective actions.

(For more on St. Helens, look at the book review GG posted a year ago; for more on Long Valley, there is a chapter in GG’s book or you can read David Hill’s review of events from his perch within the USGS).

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