Because of the 1978 forecast of a moderate quake in the area (based on seismic gap theories) and the large number of smaller-magnitude quakes following the four main jolts, the USGS issued an earthquake hazard watch on May 26, 1980 (the mid-level warning of a three-level notification system adopted by the USGS in 1977).2
But other evidence that there was something more to the mystery than tectonic forces began to stack up rapidly. A “level line” run through the valley adjacent to the major highway U.S. 395 in the summer of 1980 showed something quite odd, and quite disturbing: The area was bulging, rising slowly like a mound of dough in an oven. The rise was very small—a matter of some ten inches since 1979—but it was very significant, because it was centered over the preexisting magma chamber, which (according to theory) had been slowly cooling and contracting down to a depth of six miles below the surface over the intervening fifty thousand years (since the last significant eruption). The logical explanation for the bulge, then, would be magma pressure—new magma pressure—coming from within the magma chamber below. Perhaps the bulge, the magma chamber, and the earthquake were connected. Perhaps “the chicken or the egg” problem was surfacing in yet another volcanic setting. Did something volcanic cause the earthquakes? Or did a tectonic earthquake series trigger something volcanic?
Then there was the ominous discovery that the seismograph tracings of the Mammoth aftershocks bore a chilling resemblance to the seismographs of continuing volcanic activity beneath Mount St. Helens. What that suggested was the movement of magma somewhere beneath the street level of Mammoth Lakes, California.
The town had been picked as the site of a small conference on continental scientific deep drilling in May of 1982, an unrelated U.S. Department of Energy probe to discuss a deep-drilling geothermal project in the Mono Craters area at the north end of Long Valley. It was also a convenient midpoint location for researchers from the University of Nevada’s seismological lab and USGS scientists from Menlo Park to meet (though Roy Bailey had come from USGS headquarters in Reston, Virginia). In the cool, crisp, rarefied air tinged with the sweet aroma of pine and spruce and woodsmoke, with the vista of snowcapped peaks and the clean, if overbuilt, resort community’s collection of stores and restaurants and hotels, it was a very pleasant place to be. All the natural attributes which made the area so alluring were in evidence in the bright, sunlit afternoons and the sparkling starscape of the evenings. The setting was soothing; some of the information, however, was not.
The seismologists from Nevada had come with seismographic information on Long Valley meant to be of use to the Department of Energy’s project, but as Dr. Bailey sat up and took notice with increasing alarm, it impacted directly on his knowledge of the volcanic situation. The previous two years of earth tremors, it appeared, had not been scattered all over the caldera, as Bailey had expected. Instead, according to the Nevada seismologists, the epicenters were bunching up and becoming more frequent. And the area of those “bunched” epicenters was almost directly beneath the conferees in Mammoth Lakes, along the south margin of the caldera.
More precisely, he learned, the seismographs indicated that one area a mere two miles east of town—and almost directly beneath the only road into and out of the community—seemed more active than any others. And, it appeared that the depth of the shallowest earthquakes had been creeping closer and closer to the surface, from about five miles below in 1980 to about three miles beneath them in 1981.
Finally, the Nevada group reported that they had also confirmed the presence of “spasmodic tremors,” the phenomenon associated with active volcanoes and considered to be the result of rocks breaking under the pressure of flowing liquid rock—magma—or from the gases released by the magma.
As if to underscore the warning, a series of tremors rumbled through the town the day after the conference, shaking up an already worried Roy Bailey, the coordinator of the USGS volcanic hazards program.
Here, right at Roy Bailey’s feet, seemed to be a growing volcanic hazard. The realization that they had been mistaken to treat the earthquake patterns as merely a seismic problem weighed heavily. If there was magma moving around at depth, and if it ever reached the surface, the result would be an eruption. Knowing that the type of magma likely to surface in Long Valley was rich in silica and explosive potential—remembering the deadly pyroclastic plasma flows which had killed and destroyed everything in their paths so rapidly in the St. Helens explosion—Bailey knew with crystal clarity that this was nothing to be coy about.
A final phone call from Dr. Alan Ryall, one of the seismologists from the University of Nevada who had attended the conference and returned home the following day, was perhaps the last straw. Ryall had read the seismograms of the postconference tremors. They were now within 3.5 kilometers of the surface, he reported, squarely beneath State Highway 203, the front driveway to Mammoth Lakes and the only escape route.
That got everybody in the USGS camp excited, and immediate conferences began in Menlo Park and at USGS headquarters in Reston, Virginia, culminating in the notice that was typed up, readied for release, and delivered to the hands of the U.S. Postal Service on May 25, 1982:
United States Department of the Interior
Geological Survey, Western Region Menlo Park, California
94025
Public Affairs Office
For Release: Upon Receipt (Mailed May 25, 1982)
NOTICE OF POTENTIAL VOLCANIC HAZARD ISSUED FOR EASTERN CALIFORNIA
Because of recent changes in earthquake and thermal activity, a notice of potential volcanic hazard—the lowest of three levels of formal concern—was added today (May 25, 1982) to an existing earthquake watch for the Mammoth Lakes area in east-central California, by the U.S. Geological Survey, Department of the Interior.
In a statement prepared for state and federal emergency officials, USGS Director Dr. Dallas Peck said, “The discovery in recent months of ground deformation and new steam vent (fumarolic) activity, apparently associated with the earthquake activity, indicates that the outbreak of volcanic activity is a possibility but by no means a certainty. The concentration of these phenomena near Mammoth Lakes in the southwestern part of the Long Valley volcanic caldera suggests this as a possible eruption site, but neither the probability nor the nature, scale or timing of a possible eruption can be determined as yet.”
The notice went on to outline the “recent events” that had led to the issuance, adding, “The ultimate consequences of this activity are uncertain. It is quite possible that no eruption will occur, that the magma will cool and solidify to form an intrusion at depth.”
The immediate consequences had been economic. Now, three months later on August 25, as the meeting at Mammoth Lakes High School lumbered on, the exchange of information and forthright answers of the scientists slowly diffused some of the anger—if not the monetary loss.3
As the meeting broke up, it was obvious to the USGS men that the locals were still dissatisfied and deeply upset. They didn’t want to believe any of it. They wanted to believe the USGS had overreacted, and the lack of certainty was the key to that conclusion.
“Will our town be destroyed?”
None of the USGS men could answer that for sure.
“If an eruption does occur, how bad will it be?”
Again they had received only a broad range of possible scenarios as the answer.
“How long will it be before you guys do know anything for sure?”
Not even that question could be answered.
There would probably be adequate warning and time to get out if the worst occurred. More than that was shrouded in uncertainty. Bailey and Hill and the others could only repeat the fact that the hazard was real, but no one yet knew what would come of it. The science simply wasn’t there yet. Someday, perhaps, with enough research, and enough bright minds focused on the geologic, tectonic, volcanic, and geophysical problems—but not yet.
“Why, then,” was the recurring question, “did you issue the no
tice?”
“Because, sir, the hazard is real.”
“There are no winners,” Dr. Dave Hill would say much later. “We’re in a bind because anything we say may impact negatively [on] the economic structure. But, if something happens and we haven’t said anything, then we’ll really be between a rock and a hard place.”
The two groups were talking past each other; that much was painfully obvious. The fact that the magma, which was apparently moving around beneath their community, might explode in the near future, destroying anyone or anything in its path, seemed unreal, especially since there were no obvious changes to the landscape. All the local residents had were the words of the scientists, and the economic setback those words had brought to the community. Predictably, but unfortunately, all the things that needed to be done to prepare the community for a mass evacuation were being blocked by concern over the economic impact. If the town built an alternate escape road, for instance, it might be interpreted as a confirmation that the threat was real, and further damage the economy. Twisted thinking such as that dominated during the remaining months—until, that is, January of 1983.
Suddenly the seismographs were alive again with earth tremors from beneath the Mammoth Lakes area. Swarms of hundreds of small quakes, many large enough to feel, rumbled and rattled through the landscape, migrating ever closer to the surface, still centered near the only road into town, beneath a picturesque campground and a mountain stream.
Now the townspeople began to worry. Further deformation of the ground was documented by the scientists, and for the first time spasmodic tremors, potential evidence of moving magma, were identified on the seismograms. By mid-January the magma was less than ten thousand feet beneath them.
Suddenly the attention of Mammoth Lakes citizens was drawn to the cause, not the effect. The growing volcanic threat, and the growing worries of the volcanologists that perhaps the rise of magma would not stop until it hit the level of groundwater and built up enough pressure for a major explosion, took precedence over the economy. USGS informational meetings began to be crowded, the daily update meetings drawing little of the sound and fury of previous months. Lines appeared at grocery stores and gas stations. Property owners began purchasing earthquake insurance with volcanic hazard riders, and the Mono County supervisors began coming under fire for not having provided an alternate escape road for the town—an omission promptly corrected as a dirt road was immediately plowed from the town over the hills to the north, rejoining U.S. 395 six miles away from the epicenter of the rising magma.
Emergency evacuation warning and coordination plans were drawn up, and the county sheriff’s department began coordinating with the National Forest Service personnel, Bureau of Land Management employees, and the local fire department, figuring out what to do and how to do it if the volcanologists finally decided an eruption was imminent. For the remainder of January, each new quake and each new announcement sent shivers of fear through the residents who had innocently chosen to live in the maw of a great volcano, triggering quiet prayers and deep anxieties, and raising the inevitable question of whether this was the wrong moment in geologic time to be occupying the ancient caldera.
Then, as suddenly as they had begun, the tremors began to recede. Work on the road proceeded at flank speed, but the earth scientists watching the seismographic evidence hour by hour began to have some renewed hope that maybe—just maybe—an eruption was not on the way after all. Perhaps, they thought, the rising magma had been a dike intrusion in which molten rock had filled one of the vertically trending cracks which bordered all margins of the caldera, and had risen as far as it could go. Perhaps, in other words, it would stop short of reaching groundwater or a vent system, and thus stop short of an explosive eruption.
Slowly, caution merged into relief for the residents of Mammoth Lakes, and as March passed and the seismic activity continued to decrease, so did their interest in the reality of the volcanic processes at their feet. By May, where hundreds would have been present, only a dozen citizens attended a two-and-a-half-day USGS meeting of open presentations, even though it was held in the heart of the town.
And, just as suddenly, the unspoken moratorium on criticism of the Survey ended. Letters to the editor began appearing once again in local papers, some repeating the essentially ridiculous (and completely false) accusation that the USGS volcanologists had issued the original notice only to squeeze more funding from Congress. (One even suggested that the whole affair was a USGS maneuver to obtain government-paid vacations in Mammoth Lakes for the scientists!)
The speed with which the very real danger of January was relegated first to a false alarm, then to a grossly misinterpreted nonevent, was frightening. The fact that a disaster had not occurred was cited as proof that there was never any danger in the first place, and the focus of the community once again turned from public safety to potential economic setbacks.
“It was all a bunch of public relations hooey by the government scientists to get national attention,” the Mammoth Lakes merchant said.
“But what happens if an eruption does occur?”
“We’ll just sidestep the lava and carry on, son, that’s what.”
State and congressional representatives were peppered with demands to force the USGS to rescind its notice. At the same time, developmental plans to open a second major ski area and expand the recreational base of the community beyond the summer season and ski season began again, even though such expansion would significantly raise the number of visitors (and probably the number of residents) exposed to any renewed volcanic activity (the peak daily summer crowd was over thirty thousand, and the winter daily average above fifty thousand, and those figures were expected to double by the year 2000). While the new emergency escape road had been plowed, the developers knew well the difficulty of getting thirty thousand people out of the caldera within any reasonable period of time, even in the middle of the summer. In the winter, however, Mammoth was sometimes cut off for many hours by snowstorms. The prospect of a sudden volcanic eruption alert coming in the middle of the ski season with more than fifty thousand people trapped by snows in a community about to be annihilated by pyroclastic flows should have been a chilling prospect to anyone interested in expansion. However, the normal human tendency is to let economic growth push aside such “ethereal” concerns.
Nevertheless, the facts needed to be faced: What would Mammoth Lakes leaders and Mono County officials do in such a situation? Would there be enough time? And, of course, would it be irresponsible to permit expansion of the ski facilities, and the daily numbers of recreational visitors, in light of such a threat?
Clearly, the easiest and most cost-effective way to answer such questions was to deny the basic reason for asking them in the first place. If there was no credible volcanic threat, there was no problem. End of debate.
To their credit, the supervisors of Mono County and California authorities continued to face the problem, however weakly. (Within six months, two of the county supervisors who had been most supportive of facing reality would be thrown out of office in a recall election in the fall.)4 By June, an Incident Command System had been set up, coordinating the various emergency response agencies and their communications systems, and federal funding had been obtained to pave the emergency escape road (a project completed in nine months rather than the usual three to four years).5
There was still a missing element, however, and it was the ability of a city or county to control its citizens’ exposure to seismic risk. The same dilemma haunted Anchorage, Seward, and Valdez, Alaska, after the 1964 quake, and confronted Los Angeles and its surrounding communities with every new confirmation of what awaits in the San Andreas Fault to the north. The very same specter haunts those who know that such American cities as New York and Washington, D.C., Charleston, South Carolina, Memphis, Tennessee, St. Louis, Missouri (and many other locales), face major seismic hazards, but who also know that such cities have inadequate (or nonexistent) controls over seismic
engineering or rational land use.
The question—and the lesson—which was beginning to emerge from such controversies as that surrounding Mammoth Lakes had confronted enlightened urban planners for decades: Where, in fact, do we draw the line between public and private interests in a free society? How far can we allow ourselves as individuals or individual companies to go in accepting a major risk of natural disaster? Certainly there is a point at which our collective interests as a people to have a reasonable level of public safety must intervene (through the operation of government) to override conflicting private interests and to say, “No, you can’t build a collapse-prone convention center on that liquefaction-prone tide flat,” or, “We will not allow you to build a major hotel on a block of land that someday in the future will slide into Knik Arm,” or, “No, we will not allow the number of winter visitors potentially at risk in Mammoth Lakes to be doubled simply because you want greater profits for yourself and the community.”
We know what will happen when private economic interests win out (or governmental ignorance of a hazard prevails) and hundreds, or thousands, end up killed or injured—physically, financially, or both. We will point fingers and level accusations. We will throw out politicians and nominate committees and wring our hands. We will make loud noises about how we will never again allow something so negligent and heinous to occur.
But until something happens, it is excruciatingly difficult to bite the bullet economically and politically, recognize a hazard, and ask the ultimate question: What should we do now that we will wish we had done after a disaster?
Of course, failing to acknowledge that a threat even exists neatly blocks this process. For the people—and especially the real estate interests—of Mammoth Lakes, that denial was the solution.
But as one real estate salesman in Mammoth pointed out six months after the January scare, “We live here. We accept our own risk on our own buildings, and if we want insurance against a volcano, we buy insurance. And the USGS tells us there will be enough warning. Why shouldn’t we expand?”
On Shaky Ground Page 28