Blocked Madison River Canyon that is now Earthquake Lake
The Yellowstone Earthquake
By
Bonnie McGuire
raveling through Yellowstone Park during the summer in 2002 we made a very disturbing discovery. Driving along this lake I noticed a lot of dead trees and stumps with large dark colored birds perched on them. It seemed strange and foreboding, but if I'd known what was ahead I would have photographed them. All I remember about the birds is that they seemed eerie...
Not far up the canyon road we reach this interesting site in the photo below. We decided to park, walk up the hill to see what the boulder monument was all about.
Evidently a severe earthquake caused a massive landslide on August 17, 1959 at 11:37 p.m. Several faults in the Madison River area moved at the same time causing an earthquake that triggered a massive landslide. The slide moved at 100 mph and happened in less than one minute. Over 80 million tons of rock crashed into the narrow canyon, burying an open meadow where some campers had stopped for the night. The landslide completely blocked the Madison River and caused it to form Earthquake Lake. The force of the slide displaced both the air in the canyon and water of the Madison River. It created high velocity winds and a wall of water that swept through the area, just downstream from the slide, killing five people in its path.
The story at the top informs us that we're standing atop 300 feet of rock debris, part of the huge landslide triggered by the powerful earthquake. Prior to the earthquake, a buttress of tilted dolomite beds held the canyon wall in place. Behind the supporting buttress was a large mass of weak older rock...gneiss, schist, and amphibolite. The earthquake shook the canyon, the supporting dolomite buttress broke and with a roar, the mass of rock behind it hurtled down into the canyon. In less than a minute, over 80 million tons of rock and debris filled the canyon. Large dolomite boulders were pushed ahead of the slide and now rest on top of the debris where we are standing. These boulders were probably part of that broken buttress, the remnants of which can be seen in the slide area across the canyon.
The left sketch above illustrates the forested canyon valley with the river running through it. The right shows the 300 foot deep mountain rubble blocking the river following the earthquake.
Nineteen people lie buried beneath the landslide I'm standing on. Tragedy struck 250 campers in the Madison River Canyon when the 7.5 Richter scale earthquake shook these mountains. Choking dust clouds filled the air. Waves coursed Hebgen Lake and the Madison River. Boulders crashed, mountains slid, families were separated; some members injured, others lost forever. Escape was blocked until help arrived after daylight. The memorial plaque placed on the large dolomite boulder commemorates the 28 men, women and children who lost their lives as a result of the earthquake.
This 3000 ton boulder rode the crest of the slide across the canyon. Undisturbed lichens on it's side indicate it did not roll or tumble while crossing. The bronze memorial plaque can be seen on the other side of the boulder. The thought of tremendous power able to create a huge pile of debris 300 feet high upon the original canyon floor in less than a minute is frightening. Can you imagine that this debris could build a 2 lane highway 3 feet deep from here to New York City? That the shock of the earthquake was felt over a 600,000 square mile area as far away as Nevada and British Columbia?
Looking at Earthquake Lake up from the boulder.
And below the Earthquake Lake slide area.
The boulder...
...And directly across the canyon.
The following excerpt is from a letter written in response to newspaper article requesting personal accounts of earthquake experiences in the Intermountain West and follow-up interview submitted by Jean Ensign of Orton-Magna, Utah December 1995. Location at time of earthquake: Campground at Rainbow Point on Hebgen Lake, MT
"Rainbow Point, six miles from Hebgen Dam on Hebgen Lake, is our favorite camping spot because of the great fishing. That's where we experienced the August 1959 earthquake. That evening we ate dinner late, and didn't clean up before going to bed. I even left the eggs for breakfast out on our camper counter. The earthquake woke us up. The sound was very loud. So was my husband's swearing. We got up quickly, but slipped in spilled chili and raw eggs. The girls climbed down from their bed and began cleaning up the mess, but the shaking just kept up. When we finally got outside, we could see large pine trees all around us sway to the ground. It was hard to believe what you were seeing! My parents were camping with us in a small teardrop trailer. My husband and my mother stood for twenty minutes apologizing to each other for being in their underwear! I was frightened, but I had my family there, my mother and dad and my children, so a lot of the fear left. The one thing that scared me the most was the fact that the shocks never stopped. Those aftershocks were the worst things. There were about 50 or 60 people camped there with us. One man tried to leave, but had to return when he found large crevices in the road. We were all trapped together for three days.Everyone was cordial and helpful. My twelve-year-old daughter helped get the older people up and out. Many were nearly hysterical. One man refused to come out until he could find his teeth. Luckily my husband had pulled our boat out of the water earlier in the evening. All of the other boats were lost in the tidal wave. The boat had a radio, and that radio was the only one in camp. No news about what had happened was announced on the radio until around 6:00 or 6:30 in the morning. We heard on a California station that there had been a "small earthquake." By that time it was light, and we could see a house dropped into the lake and a huge crevice in the road that goes over to the dam and the camping area below it. There was a car in the crevice! The aftershocks never stopped.
And then someone noticed that the mountain was gone. We had been able to see it from there before, and now it was just gone!
When we learned that we couldn't get out, we all met and decided what to do. First, we put the toilet right side up. Then we did an inventory on food. There was great camaraderie. That afternoon we heard on the radio that they were worried about the campers at Rainbow Point. They asked us to please call and let them know how we were. Of course, we had no phones, so got a good laugh out of that.
A helicopter came by the second day, and someone on a bullhorn asked if we were OK. No one was hurt. Finally a bulldozer filled in the road, and we were able to leave. When we got to West Yellowstone, we stopped to call home. My husband's brother had just taken the obituaries to the newspaper with my mother and dad's pictures--the Sadler obituaries! My husband was a prominent businessman in Tooele, Utah, at that time, and the whole town was in mourning for us all.
The next year we went back to Hebgen Lake, but didn't stay. It was eerie. The mountain was down and the sun was shining through the dead trees. This whole earthquake experience was very humbling. We felt so insignificant compared to the world. We never felt closer to God."
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Brian Handwerk's January 19, 2011 article and video in National Geographic World News reminded me of the Madison River Canyon earthquake. "Yellowstone National Park's supervolcano just took a deep "breath," causing miles of ground to rise dramatically, scientists report....But beginning in 2004, scientists saw the ground above the caldera rise upward at rates as high as 2.8 inches (7 centimeters) a year. The simmering volcano has produced major eruptions—each a thousand times more powerful than Mount St. Helens's 1980 eruption—three times in the past 2.1 million years. Yellowstone's caldera, which covers a 25- by 37-mile (40- by 60-kilometer) swath of Wyoming, is an ancient crater formed after the last big blast, some 640,000 years ago." Yellowstone is a supervolcano. After reading about the tiny earthquake in the canyon, can you imagine what would happen if Yellowstone decided to blow it's top?
Yellowstone Caldera
Nova did a documentary about four scientists, working independently, from the arctic to the equator, who took ice-core samples from glaciers, and uncovered other clues that led them to discover one of the biggest supervolcanic eruptions of all time. The evidence indicates that seventy-five-thousand years ago, this mega eruption brought fire, famine and death to a quarter of the globe, and may have plunged the planet into an ice age. An ice age that began shortly after it's eruption, because of the concentration of sulfur dispersed into the earth's atmosphere. Supervolcanoes, like Yellowstone, are thousands of times more powerful than any recent eruptions; their ash and gas can cover a continent. But what makes these mega-monsters even more dangerous is how little is known about them.
