1959 — Aug 18, Earthquake, Rockfalls, Landslides, campers killed, Hebgen Lake, MT– 28

— 28 Cornell, James. The Great International Disaster Book (Third Edition). 1982, p. 151.
— 28 National Geophysical Data Center (2008). The Significant Earthquake Database.
— 28 Person. “The Hebgen Earthquake: 50 Years On,” Bozeman Daily Chronicle, Jun 20, 2009.
— 28 Searl, Molly. Montana Disasters: Fires, Floods, and Other Catastrophes. 2001, p. 16.
— 28 USGS. Deaths in the United States from Earthquakes. 2008 update.
— 28 USGS. Historic Earthquakes: Hebgen Lake, Montana, 1959 08 18 06:37:15. 2009 mod.
— 26 Highland and Schuster. Significant Landslide Events in the [U.S.]. USGS, 4-16-2003, 10.
— 18 Montana Standard, Butte. “At Least 18 are Dead in Tremors.” 8-19-1959, 1, 6-9, and 17.

Narrative Information

Person: “Martin Stryker thought it was a thunderstorm. Barb Johnson’s mom thought it was a hurricane. Don Hoggan knew it was an earthquake right away. Stryker, Johnson and Hoggan were three of the hundreds of people sleeping in tents, campers and cabins along and near the Madison River on Aug. 17, 1959, when two faults, the Red Canyon fault and the Hebgen fault, slipped and made the world shake at 11:11:37 p.m.

“The earthquake measured 7.3 on the Richter scale and was felt in Seattle to the west; Banff, British Colombia, to the north; Dickinson, N.D. to the east; and Provo, Utah to the south. That’s an area encompassing nine states and three Canadian provinces. The epicenter was about eight miles northwest of Hebgen Lake reservoir on the Madison River, where the water is held back by the Hebgen Dam — ever since known as “The Dam That Held.”

“But while Hebgen Lake miraculously remained, the earthquake left plenty of geographic scars.
Twenty-foot fault scarps that opened up that night are still visible, if grown over. The boulder that broke loose and killed Stryker’s father and stepmother hasn’t moved much.

“In Yellowstone National Park, some geysers turned off while others came out of hibernation — suggesting the earthquake rattled the geothermal pipes below the park.

“And there’s the 190-foot-deep lake that began to form after the earthquake caused an avalanche of dirt, trees and rock that plugged up the Madison River Canyon. It’s called Quake Lake.

“The human toll, too, was significant. Along with Edgar and Ethel Stryker, 26 other people were killed that night. Some were buried in the landslide. Others drowned in the making of the lake. Still others, like the Strykers, were isolated victims of bad luck.

“Still the death toll was feared to rise to the hundreds, and would have if Hebgen Dam had broken and sent 12,670 acres worth of lake down the Madison canyon toward Ennis.

“Above the dam Barb Johnson, now Barb Heinlein, was then 11 years old, staying at the Madison Arm Resort on Hebgen Lake with her mom and brother, the night of the Hebgen quake. Her dad was doing masonry work in Bozeman. When she went to bed that night in the family camper, the lake was where it had always been. The quake hit just before midnight and when the men staying at the resort decided to look at the lake after the sun came up, Johnson tagged along.
“The lake was gone. There was no water. It was one of those things that was like, ‘whoa,’” she said. “Everyone was really convinced that the dam had broken.” It hadn’t. But the lake had moved.

“According to Jeff Bowen, an interpretive guide at the Quake Lake Visitors Center on U.S. Highway 287, the north end of the lake dropped and the south end tilted up. As a result, houses on the north side of the lake toppled into the lake, while those on the south end, like Heinlein, suddenly found themselves faced with a wide swath of sandy beach….

“Geologists agree that in places where faults exist, it’s only a matter of time until earthquakes such as the one in 1959 just northwest of Yellowstone National Park hit. The Western United States is slowly stretching, and the faults are where the stretch marks show. When Southwestern Montana’s time came, blocks of rock 15 miles long abruptly slumped and shifted, Bowen, of the interpretive center, said.

“Plenty of tragedy marked that day. At least 19 people were buried by the landslide that created Quake Lake….” (Person. “The Hebgen Earthquake: 50 Years On,” Bozeman Daily Chronicle, Jun 20, 2009.)

Searl: “August 17, 1959, was much like any other summer clay in the southwestern corner of Montana. Hundreds of visitors entered and exited Yellowstone National Park through its western gate at the town of West Yellowstone. The tourist season was at its peak and the park’s campgrounds had filled early; the Gallatin National Forest campgrounds near the park were a popular alternative to late arrivals or to those who wanted to avoid the summer crowds.

“The campgrounds and cabins on the shores of thee Hebgen Lake and along the Madison River, which runs through the rugged Madison Canyon, were busy that summer. On the night of August 17, all the campgrounds in the Madison Canyon area were filled to capacity; late arrivals parked in the turnouts along the highway. Nearly three hundred campers settled in for the night.

“….Then, at 11:37 P.M., without warning, the idyllic summer night was shattered: Nearly six miles beneath the ground, Montana’s largest recorded earth¬quake was born. The shock reached the surface within seconds. When scientists evaluated the event’s intensity and magnitude, they estimated the earthquake at 7.1 on the Richter scale, but later concluded that it was probably 7.3 or 7.5. There was no doubt, however, that it was a major earthquake. For those who survived the Madison Canyon earthquake, the impact was not measured in numbers; it was measured in pain and loss…

“The first shock triggered a landslide that moved 80 million tons of rock down the mountainside; within seconds, half the mountain was relocated into the gorge below. Boulders as big as houses crashed clown the mountainside. Campers nearest the slide were buried beneath the rocks. The landslide created winds that roared through the canyon at more than a hundred miles an hour and a wall of water that thundered upstream to the Rock Canyon campground. Clouds of dust obscured the full moon and plunged the area into a suffocating darkness…. [pp. 1-2]

“on the other side of the giant landslide, most of the campers were awakened by the heaving and twisting ground. They had no idea that the mountain had fallen….All around them, boulders plunged down the hillside and crashed through the trees as aftershocks continued through the night….

“The scene in the campground was chaos. The deluge of water had hit with such force that trailers and cars were flattened into each other. Tents were tossed everywhere. Rocks and debris wreaked their havoc throughout the night…. [pp. 4-5]

“The final death toll was twenty-eight; these include the nineteen people who were buried beneath the slide; the Bennetts and Thomas Stowe, whose bodies were recovered at the base of the slide; Mr. and Mrs. Stryker, who were crushed by a boulder at their campsite at Cliff Lake; and two victims who died later at the hospital in Bozeman.” (Searl, Molly. Montana Disasters: Fires, Floods, and Other Catastrophes. 2001, p. 16.)

USGS: “This earthquake caused 28 fatalities and about $11 million in damage to highways and timber. It is characterized by extensive fault scarps, subsidence and uplift, a massive landslide, and a seiche in Hebgen Lake. A maximum MM intensity X was assigned to the fault scarps in the epicentral area. The instrumental epicenter lies within the region of surface faulting. Area of perceptibility, maximum intensity, and Richter magnitude all were larger for this earthquake than for any earlier earthquake on record in Montana (from May 1869).

“The most spectacular and disastrous effect of the earthquake was the huge avalanche of rock, soil and trees that cascaded from the steep south wall of the Madison River Canyon. This slide formed a barrier that blocked the gorge and stopped the flow of the Madison River and, within a few weeks, created a lake almost 53 meters deep. The volume of material that blocked the Madison River below Hebgen Dam has been estimated at 28 – 33 million cubic meters. Most of the 28 deaths were caused by rockslides that covered the Rock Creek public campground on the Madison River, about 9.5 kilometers below Hebgen Dam.

“New fault scarps as high as 6 meters formed near Hebgen Lake. The major fault scarps formed along pre-existing normal faults northeast of Hebgen Lake. Subsidence occurred over much of an area that was about 24 kilometers north-south and about twice as long east-west. As a result of the faulting near Hebgen Lake, the bedrock beneath the lake was permanently warped, causing the lake floor to drop and generate a seiche. Maximum subsidence was 6.7 meters in Hebgen Lake Basin. About 130 square kilometers subsided more than 3 meters, and about 500 square kilometers subsided more than 0.3 meters. The earth-fill dam sustained significant cracks in its concrete core and spillway, but it continued to be an effective structure.

“Many summer houses in the Hebgen Lake area were damaged: houses and cabins shifted off their foundations, chimneys fell, and pipelines broke. Most small-unit masonry structures and wooden buildings along the major fault scarps survived with little damage when subjected only to vibratory forces. Roadways were cracked and shifted extensively, and much timber was destroyed. Highway damage near Hebgen Lake was due to landslides slumping vertically and flowing laterally beneath pavements and bridges, which caused severe cracks and destruction. Three of the five reinforced bridges in the epicentral area also sustained significant damage.

“High intensities were observed in the northwest section of Yellowstone National Park. Here, new geysers erupted, and massive slumping caused large cracks in the ground from which steam emitted. Many hot springs became muddy.

“On the basis of vibration damage (and excluding geologic effects), damage to buildings along the fault zone was singularly unspectacular (MM intensity VIII at places, intensity VII generally). Minor damage occurred throughout southern Montana, northeast Idaho, and northwest Wyoming. Felt as far as Seattle, Washington, to the west; Banff, Canada, to the north; Dickinson, North Dakota, to the east; and Provo, Utah, to the south. This area includes nine Western States and three Canadian Provinces. Aftershocks continued for several months.” (USGS. Historic Earthquakes: Hebgen Lake, Montana, 1959 08 18 06:37:15.)

Sources

Cornell, James. The Great International Disaster Book (Third Edition). New York: Charles Scribner’s Sons, 1982.

Highland, Lynn M. and Robert L. Schuster. Significant Landslide Events in the United States. USGS, 4-16-2003. Accessed 12-15-2017 at: https://landslides.usgs.gov/learn/significantls.php

Montana Standard, Butte. “At Least 18 are Dead in Tremors.” 8-19-1959, 1, 6-9, and 17. Accessed at: http://newspaperarchive.com/FullPagePdfViewer.aspx?img=77906891

National Geophysical Data Center. The Significant Earthquake Database. NGDC, NOAA. Accessed 12-23-2008 at: http://www.ngdc.noaa.gov/nndc/struts/form?t=101650&s=1&d=1

Person, Daniel. “The Hebgen Earthquake: 50 Years On,” Bozeman Daily Chronicle, June 20, 2009. Accessed at: http://bozemandailychronicle.com/articles/2009/06/21/news/000quake.txt

Searl, Molly. Montana Disasters: Fires, Floods, and Other Catastrophes. Boulder, CO: Pruett Publishing, 2001. Google preview accessed 4-22-2020 at: https://www.google.com/books/edition/Montana_Disasters/kvhWgESXeswC?hl=en&gbpv=1&dq=montata+disasters&printsec=frontcover

United States Geological Survey. Deaths in the United States from Earthquakes (website). July 16, 2008 update. Accessed at: http://earthquake.usgs.gov/regional/states/us_deaths.php

United States Geological Survey. Historic Earthquakes: Hebgen Lake, Montana, 1959 08 18 06:37:15 UTC (local 08/17), Magnitude 7.3, Intensity X, Largest Earthquake in Montana. 10-26-2009 modification. At: http://earthquake.usgs.gov/earthquakes/states/events/1959_08_18.php