The Yellowstone Conundrum (9 page)

US Geological Survey

Geologic Hazards Science Center

Golden, Colorado 6:30 AM MST

 
Unlike Hoover Dam in Boulder Canyon on the Arizona-Nevada border and its upstream twin Glen Canyon Dam, massively overbuilt structures constructed of concrete and rebar, the upper Missouri River dams were all constructed using the hydraulic-fill method, a decision which the US Army Corps of Engineers made as America went into WWII. The Hoover Dam project, the eighth wonder of the world, was simply too expensive to replicate. It took nearly ten years to complete. The earthen hydraulic-fill dams on the Upper Missouri took three years to build.

 
The 11.2 Earthquake at Yellowstone was felt in Chicago, St. Louis, Los Angeles, Dallas, Las Vegas, San Francisco, Phoenix and Minneapolis. It was “extra felt” along the fault lines of two ancient land masses. Called the Wyoming Craton, it is a land mass encompassing the southern Rocky Mountains that over the millennia has adhered itself to the North American Craton, which is the stable land mass of the North American continent. On the eastern side of the boundary line is land with stable tectonic activity, land that has no inclination to go anywhere; west of the boundary land masses are tectonically active, everything wants to rock and roll.

 
Nancy screamed into John Temple’s ear, dropped the phone and did what you’re supposed to do in an earthquake and you’re trapped in an office building; get under a desk so you’ll have a shot at living when the building you’re in starts to collapse. As she scrambled for cover she saw in the corner of her eye across the bullpen her I/T Director Herb Probst also dive for cover; sometimes the early risers get the worm, sometimes they get the bird.

 
The strength of the massive Yellowstone earthquake reverberated like the point of a tuning fork along the ancient fault lines of the Wyoming Craton; on the eastern slopes of the Rocky Mountains, it nearly followed the path of I-90/I-25 from Billings to Albuquerque. On the Western side of the mountains, the strength of the quake traced the path of I-15 from Butte, Montana to Las Vegas, passing heavily through Salt Lake City.

 
Destruction was most severe between either edge of the Wyoming Craton because the land mass was solid rock, one great big piece of rock; vibration moves through solid rock much better than it does through fragmented material; to the west, toward California with hundreds of fault lines in Utah, Nevada and California, the effect of the earthquake was less. The overall land mass of the western US wants to move to the west and south. The earthquake in Yellowstone greatly encouraged the contest between the Juan de Fuca and North American Plates; with the Juan de Fuca, a 300-mile long ridge of undersea mountains which are continually

From upper left:
James W. Sears, University of Montana; file from Wikipedia Commons, public domain from the USGS; USGS 1999, modified 1995; Public Domain US Geo Survey

trying to go
under the North American Plate in a process called subduction.

 
As Nancy scrambled for cover, death and destruction had quickly arrived in Salt Lake City; the ancient fault line ran straight under the University of Utah. The 11.2 earthquake ripped through the city, destroying the façade of the Morman Temple and caving in the city’s sports arena, the Salt Palace. Within seconds there was massive destruction in the beautiful city. The computer and phone links from young Danny to Dr. Nancy were disconnected.

 
In Denver, on the eastern edge of the Wyoming Craton, the effect of the earthquake was more devastating because greater Denver had a population of nearly two million while greater Salt Lake had a population of 350,000.

 
Nancy screamed straight through the rumbling horror of the two minute earthquake, which was followed quickly by four more quakes of lesser magnitude. She screamed as she felt the USGS building shake, then begin to shed its exterior panels; ten-by-twenty sections of pre-fabricated fake stone, panels that fell off with a ripping sound, followed by a loss of pressure, then another rip, pop and a subsequent smash below; which was immediately followed by an intake of very cold outside air into the building.  The air whipped through the building, sweeping up papers and anything loose and light, sending the debris into a whirling dervish; whoosh and the debris smashed around the office, then finding an exit on the opposite side of the building, rushed through the floor like it had exuberant life.

I’m alive!  I’m alive!

 
It was a full four minutes before Nancy felt comfortable getting out from underneath her desk.  The lights in the office were out; power was out everywhere. It was still dark outside; dawn wouldn’t arrive for another twenty minutes.

 
Then the silence crept in like death. All that could be heard was the creepy sounds of the wind rustling what papers it could still find.

 
This is bad
Nancy thought.

Fort Peck Dam

Fort Peck, Montana

  “Bobby!” The voice came from six-foot-six “Slim-Jim” Bailey who lumbered out from the Fort Peck Visitor’s Center to greet his former direct boss, now his third-line boss, realizing the only vehicle coming across the wide expanse of nothingness would be Robert; who as usual, was right on schedule. Slim was a bit disheveled.

 
“What the hell just happened, Slim?” Robert asked.

 
“Earthquake,” Jim replied.  “Bad one; it’s still registering. Jesus, Bobby! Good to see you,” he shook Robert’s hand hard. “It’s worse,” Slim-Jim added, looking his mentor hard. No one was around, only a handful of cars in the parking lot. It didn’t take many people to operate a hydroelectric dam.             

 
“Worse?” Robert asked.

 
“In the last twenty minutes Bonneville has cut ties with us; and, Jesus, Bobby,“ Slim-Jim’s eyes were wide. “The Intertie,” Slim started, stomping a bit, turning away.  “It’s gone.”

 
The implications were Way Beyond Significant. The Texas consortium would have already shut their connections, which meant no electricity was being sold between the western states and the eastern states; which meant people in Maine who were on electricity instead of gas were sucking the big wand along with everyone in New York, Pennsylvania, nearly 60% of the US, and the power companies weren’t going to be able to produce the instant electricity needed to supply toasters and electric toothbrushes and electric blankets and city lights and….WOOOOSH…it was the sound of a straw sucking an empty soda bottle.

 
Robert’s brain had to clear all of the things he couldn’t do anything about.

 
“Are we OK?” he asked.

  Slim-Jim’s eyes were cloudy.
He started to shake his head but didn’t say anything.  “I don’t know, Bobby,” he hesitated. “I’m not sure yet. Let’s go inside. This can go either way,” replied the Power Plant Manager.

 
This wasn’t going to be the drill I thought it was going to be
thought Robert O’Brien. 

 
The pair entered the Operations Center.

 
“Too many red lights, Slim” Robert remarked at the control center’s scoreboard. “What are these?” he asked.

 
“Come on, Bobby; this is your stuff,” Slim added. The control center had four people on consoles, two of which doubled as maintenance for other parts of the dam; it was lonely duty in the most desolate part of the lower US.

 
“Registrations?” Robert asked.

 
“Yes,” replied Slim-Jim.

 
“Sweet, Jesus,” Robert replied.

 
“Amen,” added his new manager.

 
The Fort Peck Dam was talking.

 
Nobody built earthen dams any more because they were susceptible to guess what--EARTHQUAKES!
 

 
Well, duh
.

 
The newly installed registration board was lit by reports from seismic equipment buried deep within the dam.

 
“Liquefaction,” Robert muttered, now really nervous.  Slim-Jim’s eyes were wide open.

 
Soil liquefaction occurs in an earthen dam when the soil—saturated with water loses its strength and stiffness; the breadth of the dam, in response to an applied stress such as an earthquake. In layman’s terms, the soil becomes so disturbed that the water in the soil changes form, from soil to something very much like quicksand. The liquefied soil then appears to have a choice, to remain as is, or to pass the liquid back and forth between the soil particles, kind of “sloshing” due to the external forces.

 
“Sloshing” on a larger scale could mean the fault of a large earthen dam because the soil structure, the massive amount of dirt and landfill, begins to lose its strength, and more importantly—instead of behaving like a solid, the “sloshing” turns the soil into a liquid, thus soil liquefaction.

 
In other words, it’s a bugger to fix once it starts.

 
“Do you think it’s going to go?” asked Robert.

 
Slim-Jim Bailey’s eyes were bugged. 

 
“I’ve started shut down.  I don’t have a clue, Bobby.”

  
The two managers walked out to the large expanse of the Fort Peck Dam.

 
“Look over there!” Robert exclaimed. His mouth, dry before, lost even the thought of a pucker as his eyes scanned the mile between the power plants and the berm of the dam over looking Fort Peck Lake; as of yesterday morning the massive 134-mile long lake was seven feet three inches above the “full pool” level of 2234 (above sea level) at 2241.3.

 
What they saw should have been impossible. Across the wide, grassy expanse to the east the ground was actually moving; a slow dance where the ground became soft, chewy in consistency, then began to form little circles of ten feet in diameter with a donut hole in the middle. And there was nothing they could do about it. There wasn’t a bag of hurt-no-more they could put on the wound. 

 
“My God in heaven,” Slim-Jim swore. “Sand boils.” 

 
The dam was squeezing sand out from its core below due to the pressure of the earthquakes vibration; all across the face of the mile wide sloping surface of the earthen dam tiny sand volcanoes were being formed. Water filled the center of the holes.

 
“I don’t suppose you can order an army of compactors,” Robert asked, his belly queasy.

 
“I can’t order you a pizza, Bobby,” the plant manager replied.

 
Robert smiled but walked away from downstream visitor’s center. The concrete walkways connected the center with the double seven-story power plants a quarter mile away. To his left the uphill slope was hard to see, but walking it was different and clear. The long walkway connected the business part of the dam with the berm, or crest, of the dam itself. 

 
Robert left the walkway and started walking uphill on the packed dirt. The ground was frozen solid—except for little vents of heat that caused vapor streams. The closer he got to the center of the field, the warmer it got. He could feel the temperature change; maybe now up to 14 degrees.

 
The sand boils looked like the suction cups of an octopus on a piece of glass as seen from above; nothing in nature looked the same. Robert looked down the 4-mile length of the dam. He couldn’t see past fifty yards with any detail.

 
Nancy, I hope you’re OK; because I’m not
.