So imagine you have your own piece of sweet reality in eastern California. You're a business owner in the resort town of Mammoth Lakes, when over the
course of several years, massive earthquakes start happening, along with intense earthquake swarms, gas emissions and ground inflation- all around and
in the caldera. And there is talk of a massive volcanic hazard right in your own back yard coming from the scientific community.
How would you react?
Well in order to get a further understanding of the grave events that occurred there and which caused considerable anguish to the many communities in
and around Long Valley, I emailed one of my many scientific sources about this. I was sent an interesting document, which goes into considerable
detail about this very subject, and the tense atmosphere of those trying times. Public reactions to the intense volcanic unrest varied widely. Many
scientists were shunned, and some business owners even put up "Geologists Not Welcome" signs on their storefronts.
As scientists wrestled with the ongoing unrest, a series of Long Period volcanic events began under Mammoth Mountain, prompting further alarm bells.
It really was "downright scary," as one of my other sources has recounted to me in emails over the years.
Here they had a supervolcano, with potential to bring some serious devastation to the entire western seaboard of the US, exhibiting just about ALL of
the signs of a potential eruption looming: Big quakes M>6, ground deformation with the resurgent dome rising at an increasing rate, increased magmatic
CO2 emissions saturating the ground, intense earthquake swarms, and long period events detected so close together it bordered on being volcanic
And as it turns out, the current volcanic alert system was actually developed from the events that occurred there, as scientists struggled with
disseminating emerging information to an extremely skeptical and even vindictive, public.
So in order for you to understand the setting for this, and just how bad this got, have a look at this, from the document I was sent (sorry, you guys
just gonna have to trust me on this one, as I cannot provide a source link- but suffice it to say this came from a well respected scientist, written
A M~ = 5.8 earthquake on October 4, 1978, located beneath Wheeler Crest 14 km southeast of Long Valley caldera (roughly midway between Bishop and
Mammoth Lakes), marked the onset of the extended episode of unrest in the caldera and vicinity that continues today. Over the next year and a half,
seismic activity in the form ofM > 3 and occasional M > 4 earthquakes gradually migrated toward the northwest and the southern margin of the caldera.
Then, on May 25, 1980, just seven days after the catastrophic eruption of Mount St. Helens, three M-6 earthquakes shook the southern margin of the
caldera, accompanied by a rich aftershock sequence.
By the morning of May 27, the USGS had released a formal "Hazard Watch" noting the possibility of additional M-6 earthquakes in the area. Just hours
later, a fourth M-6 earthquake shook the area--a successful "shortterm" forecast!
Jim Savage and Malcolm Clark promptly made arrangements to have a section of Highway 395 through the area releveled to document the coseismic
displacement expected from this series of four M-6 earthquakes. What they found instead was a broad, dome-shaped uplift of the caldera floor (the
resurgent dome). Monuments near the center of the resurgent dome were 25 cm higher in the summer of 1980 than they had been in 1975. Measurements of a
trilateration network spanning the area made in 1979 suggested that most, if not all, of this deformation developed sometime between the summer of
1979 and the summer of 1980. With fresh images of Mount St. Helens in mind, it required no great leap to recognize a volcanic signature in this
combination of strong earthquake swarm activity and ground deformation. Still, if the activity had died away as with most aftershock sequences, I
suspect our collective attention would have soon focused elsewhere.
Earthquake activity continued, however, with frequent swarms that included locally felt earthquakes (M-3--4 events), rapid-fire bursts of small
earthquakes reminiscent of "spasmodic tremor" seen at some volcanoes, and evidence that focal depths were getting shallower with time. In
discussions including a number of us in the USGS, the California Division of Mines and Geology (CDMG), and Alan Ryall at
the University of Nevada, Reno over the winter of 1981-82, a consensus developed that we had an obligation to inform local civil authorities of our
concerns about the volcanic nature of this activity. A formal draft of such a statement went to the USGS Director's office, followed by an
dialogue between the Director's office and the Governor's office in Sacramento over the precise wording of this announcement and how and when it
should be released. Officials for Mono and Inyo Counties remained in the dark.
Meanwhile, George Alexander, then a science writer for the Los Angeles Times, got wind that something was up. His article announcing that the USGS was
about to release a "Notice of Potential Volcanic Hazards" for the area appeared in the Los Angeles Times on the morning of May 24, 1982 (the Monday
before Memorial Day weekend and just one day before the second anniversary of the May 1980 M -6
earthquakes). This, of course, caught both local civil authorities and the citizens of Mono County completely by surprise and short-circuited the
official "Notice of Potential Volcanic Hazards" (the lowest level in the Notice/Watch/Warning hazard terminology in use by the USGS at the time),
was released the next day. The local response was one of outrage, anger, and disbelief ("What volcano?!"), exacerbated by inflammatory headlines and
news stories about "brewing lava eruptions" and a town in denial (the Jaws syndrome).
Geologists, and USGS geologists in particular, immediately became personae non gratae in Mammoth Lakes and Mono County, an attitude that only
gradually mellowed over the years. Under the best of circumstances, communicating information on a newly recognized hazard is tricky business; this
stands as an outstanding example of how to start out on the wrong foot.
(Continued next post)