Idaho History Apr 5, 2020

Idaho Earthquake History

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Historical Earthquakes in Idaho

1. Nov 10, 1884. Paris, Franklin County, Idaho
The earthquake damaged houses considerably in Paris, about 100 km southeast of Pocatello, near the Idaho-Utah-Wyoming border. It knocked down chimneys and shook stock from shelves in Richmond, Utah, about 125 km north of Salt Lake City. In an area north of Ogden, Utah, the tremor shook a Utah and Great Northern Railroad train. Also reportedly felt at Salt Lake City, Utah, and Franklin, Idaho.

2. Nov 11, 1905. Near Shoshone, Lincoln County, Idaho
Cracks formed in the walls of the courthouse and schools in Shoshone, and plaster fell from ceilings in almost all the buildings. Felt from Salt Lake City, Utah to Baker, Oregon.

3. Oct 14, 1913. North-central Idaho
A tremor broke windows and dishes in the area of Idaho and Adams counties.

4. May 13, 1916. Boise, Idaho
The earthquake wrecked several brick chimneys at Boise and sent residents rushing into the street. The shock was described as “violent” at Emmett, 40 km north of Boise, and at Weiser, 96 km west of Boise. Reclamation ditches in the area were damaged. Pressure in a new gas well increased noticeably immediately after the shock. Also felt in western Montana and eastern Oregon.

5. Nov 25, 1924. Near Wardboro, Franklin County, Idaho
A slight earthquake in Franklin County on this date broke windows at Wardboro, cracked ceilings at Montpelier, and displaced furniture at Geneva and Montpelier.

6. Near Sheep Mountain, southwest Idaho [1944?]
This earthquake apparently was most severe in the area of Fontez Creek, near Sheep Mountain, Idaho, where buildings were shaken so severely that occupants thought the structures were falling apart. A new cabin set on concrete piers was displaced on its foundation. Along Seafoam Creek, rocks and boulders were thrown down the hillside.
Cracks about 30.5 m long formed in the ground in the Duffield Canyon trail along Fontez Creek. Cracks 2.5 to 7.5 cm wide extended for several meters in a continuous break near Seafoam. A section of the Rapid River Canyon wall (near Lime Creek) fell into the river. Also felt in Montana, Oregon, and Washington. Seventeen shocks were reported felt, the first of which was the strongest.

7. Feb 14, 1945. Idaho City, Boise County, Idaho
This tremor broke dishes at Idaho City and cracked plaster at Weiser, northwest of Boise in Washington County. Also felt in Montana, Oregon, and Washington.

8. Sept 25, 1947. Boise, Ada County, Idaho
Several large cracks formed in a well-constructed brick building at Boise, but damage generally was slight.

9. Dec 19, 1957. Northern Idaho
Timbers fell and mine walls collapsed at the Galena Silver mine near Wallace, Shoshone County.

10. Aug 7, 1960. Near Soda Springs, Caribou County, Idaho
Southeast of Pocatello and about 14 km east of Soda Springs, cracks formed in plaster and a concrete foundation at a ranch.

11. Jan 27, 1963. Clayton, Custer County, Idaho
Plaster and windows cracked at Clayton, northeast of Boise. Large boulders rolled down a hill at Livingston Camp, about 22 km south of Clayton. Several aftershocks were felt in the area.

12. Sep 11, 1963. Central Idaho
Plaster fell in buildings at Redfish Lake, south of Stanley in Custer County; a window pane was broken at a fire station in Challis National Forest.

13. April 26, 1969. Ketchum, Blaine County, Idaho
Cracks formed in concrete floors of structures in Warm Springs and Ketchum. Plaster was cracked at Livingston Mill, 20 km south of Clayton.

14. Mar 28, 1975. Eastern Idaho
In the Ridgedale area of the sparsely populated Pocatello Valley, this earthquake shifted several ranch houses on their foundations and toppled many chimneys. At Malad City, 20 km northeast of the epicenter, about 40 percent of the chimneys on old buildings were damaged. Total property damage was estimated at $1 million.
Geologists observed one zone of ground fractures – about 0.6 km long and 5 cm wide – in the south-central section of the valley.

15. Nov 27, 1977. Cascade, Valley County, Idaho
Property damage was reported only at Cascade, a few kilometers east of the epicenter, near Cascade Dam. The tremor cracked foundations and sheetrock walls, separated ceiling beams, and left muddy water in wells and springs. Also felt in Oregon.

16. Oct 24, 1978. Southeast Idaho
Cracks formed in plaster and a concrete foundation at Thatcher in Franklin County. This earthquake was felt in Bannock and Franklin Counties of southeast Idaho, and at Plymouth, Utah, south of Pocatello, Idaho.

17. Oct 14, 1982. Near Soda Springs, Caribou County, Idaho
In the Soda Springs area, about 45 km southeast of Pocatello, bricks fell from chimneys and cracks formed in the foundation of a house and interior drywalls. Also felt in Utah and Wyoming.

18. Oct 28, 1983. Borah Peak, Custer County, Idaho
The Borah Peak earthquake is the largest ever recorded in Idaho – both in terms of magnitude and in amount of property damage. It caused two deaths in Challis, about 200 km northeast of Boise, and an estimated $12.5 million in damage in the Challis-Mackay area. A maximum MM intensity IX was assigned to this earthquake on the basis of surface faulting. Vibrational damage to structures was assigned intensities in the VI to VII range.

Spectacular surface faulting was associated with this earthquake – a 34 km long northwest trending zone of fresh scarps and ground breakage on the southwest slope of the Lost River Range. The most extensive breakage occurred along the 8 km zone between West Spring and Cedar Creek. Here, the ground surface was shattered into randomly tilted blocks several meters in width. The ground breakage was as wide as 100 km and commonly had four to eight en echelon scarps as high as 1-2 m. The throw on the faulting ranged from <50 cm on the southern-most section to 2.7 m south of rock creek at the western base of Borah peak.

Other geologic effects included rockfalls and landslides on the steep slopes of the Lost River Range, water fountains and sand boils near the geologic features of Chilly Buttes and the Mackay Reservoir, an increase or decrease in flow of water in springs, and fluctuations in water levels. A temporary lake was formed by the rising water table south of Dickey.

The most severe property damage occurred in the towns of Challis and Mackay, where 11 commercial buildings and 39 private houses sustained major damage and 200 houses sustained minor to moderate damage.

At Mackay, about 80 km southeast of Challis, most of the commercial structures on Main Street were damaged to some extent; building inspectors condemned eight of them. Damaged buildings were mainly of masonry construction, including brick, concrete block, or stone. Visible damage consisted of severe cracking or partial collapse of exterior walls, cracking of interior walls, and separation of ceilings and walls at connecting corners. About 90 percent of the residential chimneys were cracked, twisted, or collapsed.

At Challis, less damage to buildings and chimneys was sustained, but two structures were damaged extensively: the Challis High School and a vacant concrete-block building (100 years old) on Main Street. Many aftershocks occurred through 1983. Also felt in parts of Montana, Nevada, Oregon, Utah, Washington, Wyoming, and in the Provinces of Alberta, British Columbia, and Saskatchewan, Canada.

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source: Idaho Geology [h/t ID AHGP]
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Valley County Fault Map


(link to larger size at source)

source: Digital Atlas of Idaho
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Idaho Earthquake History USGS

The first earthquake causing damage in Idaho’s earthquake history occurred on November 9, 1884, apparently centering in northern Utah. Six shocks were reported felt at Paris, Idaho, causing considerable damage to houses. People suffered from nausea.

A shock on November 11, 1905, was felt in the southern half of Idaho and parts of Utah and Oregon. At Shoshone, Idaho, walls cracked and plaster fell.

On May 12, 1916, Boise was hit by a shock which wrecked chimneys and caused people to rush into the streets. Reclamation ditches were damaged and the flow of natural gas altered. It was felt at Loon Creek, 120 miles northeast, and in eastern Oregon – an area of 50,000 square miles.

An intensity VII earthquake occurred within the State on July 12, 1944. The Seafoam Ranger Station building shook so hard the occupants thought it was coming apart. Several people reported that the shaking was so violent they were unable to walk. Another observer reported that rocks rose at least a foot in the air and looked like a series of explosions up the hill. Part of the canyon wall collapsed near Lime Creek. Cracks opened 100 yards long in Duffield Canyon and cracks one to three inches across and several hundred yards long opened on the road below Seafoam. Two chimneys fell at Cascade. This shock was felt over 70,000 square miles, including all of central Idaho, and parts of Washington, Oregon, and Montana.

The magnitude 7.1 earthquake at Hebgen Lake, Montana, on August 17, 1959, which killed 28 people, formed “Quake Lake,” and did $11 million damage to roads and timber, also caused some damage in Idaho. Intensity VII was experienced in the Henry’s Lake, Big Springs, and Island Park areas. Big Springs increased its flow 15 percent and became rusty red colored. A man was knocked down at Edward’s Lodge. There was considerable damage to building in the Henry’s Lake area. Trees swayed violently, breaking some roots, and cars jumped up and down. Chimneys fell and a 7-foot-thick rock-and-concrete dock cracked.

In the Island Park area chimneys were toppled and wells remained muddy for weeks. At Mack’s Inn, a small girl was thrown from bed and hysteria occurred among some guests. Dishes were broken.

An intensity VII earthquake occurred on August 30, 1962, in the Cache Valley area of Utah. Two large areas of land totaling four acres, five feet thick, slid 300 yards downhill at Fairview, Idaho, opening new springs. Plaster walls, and chimneys were cracked and a chimney fell at Franklin. Falling brick at the Franklin School cracked through the roof and plaster was cracked in every room. Additional damage occurred at Preston. This magnitude 5.7 earthquake was felt over an area of 65,000 square miles in five states and cause approximately $1 million in damage.

An intensity VI shock, on November 1, 1942, centered near Sand Point and affected 25,000 square miles of Washington, Montana, and Idaho. The Northern Pacific Railroad partially suspended operations to inspect the right of way for boulders and slides. Church services were interrupted, but only minor damage was reported by homes.

A February 13, 1945, shock near Clayton, felt over a 60,000 square mile area, broke some dishes at Idaho City and cracked plaster at Weisner.

A locally sharp shock was felt at Wallace on December 18, 1957, damaging the Galena Silver Mine and frightening miners working 3,400 feet underground.

Soda Springs was shaken by a shock on August 7, 1960, which cracked plaster and a concrete foundation. It was only felt over a 900 square mile area.

Two intensity VI shocks were reported in 1963. The first on January 27, was felt over 6,000 square miles and centered near Clayton, where plaster and windows were cracked. Large boulders rolled down the hill near Camp Livingston and aftershocks were felt for a week. The second occurred on September 10 and was a magnitude 4.1 shock. It caused minor damage at Redfish Lake. Thunderous earth noises were heard.

A magnitude 4.9 shock on April 26, 1969, cracked a foundation at Ketchum, plaster at Livingston Mills, and a cement floor at Warm Springs. It was felt over 9,000 square miles.

Abridged from Earthquake Information Bulletin, Volume 4, Number 2, March – April 1972.

source: USGS
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1872 Earthquake

Major Earthquake Rocks Idaho Panhandle and the Pacific Northwest

by Evan Filby

Late on the evening of Saturday, December 14, 1872, residents in North Idaho felt a major earthquake that swayed buildings, caused shelved objects to rattle around, and agitated animals. In its report of the incident, the Lewiston Signal said, “The violence of the first shock created considerable alarm among those who had never experienced such a thing before.”

The initial strong shock stopped clocks, and rattled crockery and glassware all around the region. Many Lewiston residents heeded the normal advice and ran out into the streets. Those who had gone to bed felt their berths rock and sway along with their home or hotel. Some thought a sudden, tremendous gust of wind had hit.

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U. S. Geological Survey image, retouched to focus on 1872 event.

The Signal wrote that during the quake, “Frightened chickens flew about as though possessed of the devil. Dogs howled, cattle lowed, and all nature, animate and inanimate, was much disturbed.”

Elk City is located deep in the Idaho mountains, nearly ninety miles to the southeast of Lewiston. There, residents felt the quake “very plainly.” At that time, only scattered ranches occupied Paradise Valley, future location of Moscow. The Signal article said, “North of here, in the vicinity of Paradise valley, the shock was so severe as to make everything fairly dance.”

Most witnesses reported a short, sharp initial jolt: It lasted about eight seconds in Lewiston. However, at least one Idaho location along the Clearwater River reported that the shaking lasted around two minutes. Despite the relative severity of the quake, no one observed any soil or rock displacement, nor any serious structural damage.

Idahoans recorded at least three quick shocks and others apparently felt four. These were all within a few minutes of the first event. No one in Idaho reported any delayed aftershocks. However, several locations between the Idaho border and the Cascades – many in Washington and a couple in Oregon – recorded intermittent aftershocks into the early morning hours.

Contemporary accounts indicate that people felt the quake all over the Pacific Northwest, including parts of Montana and Canada. In Wallula, Washington, 20-25 miles west of Walla Walla, witnesses reported a heavy shaking that lasted almost a minute, followed by five lighter shocks accompanied by rumbles like “a heavy peal of thunder.” In Portland, people noticed swaying chandeliers and some stopped clocks, but no actual damage.

Reports were not without an element of humor: The Oregonian had a statement from Walla Walla that said, “The accounts that reach us seem to indicate that the further north, the greater the severity of the earthquake. There is a report that up in the Spokane country, the earth opened and swallowed up a number of Indians and their horses. This, doubtless, is an exaggeration … ”

The quake hit much harder around Puget Sound and Vancouver Island. There, many buildings “swayed to and fro like small craft at sea.” As in Lewiston, residents ran into the street for fear the structures would collapse. A number of windows broke, and homes and restaurants found “crockery tumbled from the shelves.”

Back then, of course, there was no seismograph network to provide objective measurements. However, analysis of various motion and damage reports provide an estimated magnitude of 6.8 to 7.4 – a strong to major event. Other assessments placed the epicenter in the foothills of the Cascades about 100 miles east of Seattle.

References: [Illust-North]
William H. Bakun, Ralph A. Haugerud, Margaret G. Hopper, Ruth S. Ludwin, “The December 1872 Washington state earthquake,” Bulletin of the Seismological Society of America, Vol. 92, No. 8, pp. 3239-3258 (2002).

source: South Fork Companion
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1915 Earthquake

Emmett Index, October 7, 1915

1915EmmettQuake-a
EARTHQUAKE FRIGHTENED EMMETT
Buildings Shook — Clocks Stopped — Chickens Shook from Roosts — No Damage.

An earthquake shock that lasted at least a minute struck Emmett at 11:55 Saturday night and caused general consternation. Brick buildings trembled, frame buildings swayed, clocks stopped, electric lights suspended by cords swayed to and fro like pendulums of clocks, chickens were shaken from their roosts and people roused from their slumbers by the swaying of the beds, the rattling of windows and the creaking of doors and joints. In short, Mother Earth acted as if she had been on a spree and with unsteady gait was trying to make her way upstairs to bed without disturbing the old man and had made the usual bungle at it. No damage was done, except to the of the nerves of timid and of those with guilty consciences.

The direction of the quake was from west to east or visa versa. Clocks whose pendulums swung north and south stopped. Those swinging east to west gained momentum and pounded the sides of their cases. Brooms suspended in a rack in McNish’s store swung in the same direction a distance of five feet each way as did also a bundle of whips, and electric lights. Sam Motz was just reaching for the door knob of his back door upon his return from the dance, when the quake occurred, and he missed the knob a foot as the house swayed to the east, and missed it again as it swung back. He thought some one had “spiked” the city water and it had effected his head.

Arch McKellar, the Squaw creek rancher, was engaged in a social game of solo at the Brunswick. The lights swayed, the pop bottles crashed against each other, cigars got up on their hind legs and walked, the queen of spades winked at him and the jack of clubs made a pass. That was too much for Archie; he rushed for the door, leaving his hinkeys on the table.

Tom Hance was toasting himself before the fire. He had a severe cold and had been taking cough medicine, When everything began to swim before his eyes he thought he had taken too much of the stuff and it had gone to his head.

Bob Knizer, who was asleep, thought the dog had gotten under the bed and was bouncing the bed springs up and down. D. M. Stokesbery’s wife thought her husband was trying to bounce her out of bed, and Ora Bever scolded his wife for kicking so hard . The effect upon Allen Gatfield was to make him sick at his stomach, and others were affected the same way. Herb Blackman rushed down town, expecting to see every brick building in ruins. The city water tower swayed, and the iron braces scraped against each other and made an awful noise, something like a symphony orchestra playing the Dance of the Valkyries.

At the Russell hotel the guests were badly frightened and rushed panic stricken from their rooms and down stairs, clad in sundry and divers garments.

So far as the news agencies have been able to learn little damage has resulted from the earthquake, although it was general all over the western country. It was felt from Victoria B. C. to Fresno, Cal.; and as far east as the Rocky mountains. It was the heaviest in Nevada and Utah, but no casualties or material damage is reported from either state. In Utah there was a slip in the Wasatch mountains for 150 miles, and this caused a third shock which many people thought was another earthquake. In Boise the tremor was felt for nearly two minutes while at Ontario it is reported that it cracked the plaster in the Moore Hotel. Practically all southern Idaho and eastern Oregon towns felt the shock. At Baker City a panic was narrowly averted, and at Vale the shock was quite severe.

source: The Emmett Index. (Emmett, Idaho), 07 Oct. 1915. Chronicling America: Historic American Newspapers. Lib. of Congress.
[h/t SMc]
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1944 Earthquake

Strong Earthquake Rocks Central Idaho

by Evan Filby

In the early afternoon of July 12, 1944, a quick double-punch of earthquakes hit south-central Idaho. Later analysis placed the epicenter about forty-two miles west, and slightly south, of Challis, Idaho. Oddly enough, the quake was apparently not noticed there – at least the Challis Messenger carried no report.

The magnitude 6-7 quake severely impacted the Seafoam Ranger Station, located about ten miles north of the estimated epicenter. Witnesses there thought the station building might collapse, and several said “they were unable to walk.” They also observed drastic rock dislocations, a slumped canyon wall, and one- to three-inch cracks running several hundred yards along the forest service road. At Cascade, 45-50 miles to the west of the epicenter, the quake toppled two chimneys.

Newspapers in southwest Idaho and over into Oregon had many reports, although none mentioned such dramatic affects. At Garden Valley, about fifty miles distant, people simply reported feeling a tremor. Yet at Idaho City, a few miles further from the epicenter, the County Clerk said the county building shook “noticeably.” McCall was about sixty miles northwest of the epicenter. There, witnesses distinctly felt the shock and a housewife said her kitchen floor “danced.” None of these locations reported any damage.

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Epicenter and locations where reports originated.

At Fairfield, 70-75 miles south, witnesses reported swaying structures, swinging light fixtures, and rattling dishes. Again, there was no damage in that area. In Emmett, the tremor caught two workmen trying to handle a barrel of chilled water. Each suspected a prank as water sloshed onto one and then the other. The story claimed that the two “almost came to blows” before they figured out what was going on.

Residents in Nampa, Caldwell, Payette, and Weiser mentioned no such drama, but said they distinctly felt the tremors. Ontario, Oregon and another village about fifty miles further west also reported feeling the shocks. Observers in Helena, Montana, about 220 miles away, reported a minor tremor about the same time, but that may have been a local quake.

As might be expected, Boise produced numerous stories. Jolts strong enough to dump dishes on the floor sent some people rushing into the streets. At one fire station, the firemen themselves joined the general rush when their building began to sway and shake. Calls swamped switchboards at police stations, fire departments, and newspapers offices, wondering if there’d been an explosion.

A few folks even wondered if there had been an air raid. Quite a leap of imagination: Allied troops had staged the “D-Day” landing in Europe about six weeks earlier, and the U. S. Navy had crushed Japanese forces at the “Battle of the Philippine Sea” less than a month earlier.

A dental patient bolted from her chair at the first movement. Elsewhere, furniture scooted around and clocks stopped. One woman saw an empty rocking chair suddenly began to sway back and forth. Having no other clues, she found the sight “the most frightening experience of her life.” Some witnesses thought they were ill, and having a sudden dizzy spell. At least one older man remarked, “I thought I was having a heart attack when my chair started shaking.”

Seismographs across the West recorded the shock, including stations in Salt Lake City, Spokane, and Pasadena. A seismologist at the University of Utah opined that had the epicenter been closer to a city with larger structures, “it would have toppled a lot of chimneys.”

References: “Central Idaho Earthquake,” Daily Bulletin, Blackfoot, Idaho (July 12, 1944).
“Idaho Earthquake History,” Earthquake Information Bulletin, Vol. 4, N. 2, U.S. Geological Survey (March – April 1972).
“Newspaper Articles for 1944 Central Idaho Earthquake,” University of Utah Seismograph Stations.

source: South Fork Companion
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1959 Hebgen Lake earthquake

The 1959 Hebgen Lake earthquake (also known as the 1959 Yellowstone earthquake) occurred on August 17 at 11:37 pm (MST) in southwestern Montana, United States. The earthquake measured 7.2 on the Moment magnitude scale, caused a huge landslide, resulted in over 28 fatalities and left US$11 million (equivalent to $96.48 million in 2019) in damage. The slide blocked the flow of the Madison River, resulting in the creation of Quake Lake. Significant effects of the earthquake were also felt in nearby Idaho and Wyoming, and lesser effects as far away as Puerto Rico and Hawaii.

… The earthquake also caused damage and fatalities outside of Montana. In Raynolds Pass in Eastern Idaho, a landslide killed eight more people. Seismic waves from the quake were reported in Boise and Macks Inn, Idaho, causing minor well and sewer damage.

continued: Wikipedia
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1959QuakeScarp-a
Description Landslides from the 1959 Hebgen Lake earthquake, in West Yellowstone.

Location (TGN) Madison Valley
Creator Warren Bybee
Source Gracie Pfost Papers, MSS 175, Box 3 Folder 16, Boise State University Special Collections and Archives.
Contributing institution Boise State University, Albertsons Library Special Collections and Archives

source: w/larger photo from BSU
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The Hebgen Lake Earthquake on August 17, 1959

January 22, 2010 by Arne

In 1999, the Denver Post‘s Ann Schrader wrote a long 40-year anniversary retrospective on this earthquake, which happened very close to Yellowstone. She explained that at 11:37 that summer evening “an earthquake measuring 7.5 on the Richter scale jerked and jolted an eight-state area for 30 to 40 seconds.

“When stillness finally returned, 26 people camped about 10 miles northwest of [West Yellowstone] were buried alive when a mountainside collapsed in the Madison River Canyon. The 8,000-foot mountain poured an estimated 85 million tons of rock on the U.S. Forest Service campground at a speed of about 100 mph. In the end, only seven bodies were found. Two more people in the area who were hurt died later of quake-related injuries.”

It “also created a new lake [Quake Lake] on the Madison River behind the landslide, collapsed five sections of U.S. 287 into Hebgen Lake, dropped sections of land 20 feet, and rearranged the plumbing of geysers and hot springs in Yellowstone.”

Earth Magazine used the 50th anniversary as an occasion to write about the quake. Here’s a story from its article:

Link: to continue reading The Hebgen Lake Earthquake on August 17 1959
(Note this article has many interesting stories)
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A Hebgen Lake Earthquake Memory – 1959

March 3, 2010 by Arne

Last month, while looking for some more information on the Hebgen Lake earthquake, I came by the Madison Valley Historical Association in Montana and saw its quarterly newsletter on its website. A copy of the newsletter from July 2009 featured several stories from people who’d experienced the 1959 earthquake. I wrote to ask permission to reprint one story from Dixie Robison Marosok. She and the association agreed to the reprint, and here is her story:

We were married in August of 1958 and my husband, Jim, enrolled at Montana State College in Bozeman where he could work toward a degree in geology. When spring arrived, we were looking for a summer job and my sister, Jerry Lower, called. She and her husband, Don, worked on the Cedar Creek Ranch for John Uihlein just outside of Ennis. (John was an heir to Schlitz beer). Don offered Jim a summer job and Jerry offered me the job of sharing cooking duties for the ranch crew. We gladly accepted and on the 17th of August, we were living at the Cedar Creek Ranch in the same range of mountains as the earthquake site, the Madison Range.

We had a busy day on Aug. 17th preparing for John Uihlein’s 40th birthday which fell the next day. I was expecting our first baby in early September and was tired and anxious to finish and get some sleep. It took some time to settle down after the hectic day and the night was very still and quiet. Just a couple of hours after going to bed, I was awakened by the rocking and shaking of our bed. I woke Jim, saying that a bear had crawled under the cabin. He laughed at me as he was immediately aware that it was an earthquake, and we rushed to look out the window.

The earth was rippling in waves like a windblown lake as the tremors moved through the grass. I will never forget that sight. As we attempted to get back to sleep, I began to experience some early labor pains. We were getting ready to call Doc Losee when the pains finally stopped and we returned to bed.

The next morning the valley was full of dust and up on the mountains you could see clouds of dirt raising above the trees. Aftershocks continued through the day. As people began arriving for John’s party, we learned of the earthquake site and the tragic slide that buried and injured so many campers. We were also told of the closure of the road through Ennis. Thankfully we hadn’t needed the hospital since it was on the opposite side of the river and with the road closed, we couldn’t have reached it. Reports came in that many people had fled to high ground and some even took refuge in Virginia City across the mountains.

John’s party went as planned but all everyone could think of was the earthquake and the tragedy of the rock slide that killed so many people in the canyon campgrounds.

Within three weeks I was in the hospital where Doc Losee delivered our first son, Michael. I had some unusual visitors along with my family. Two or three of the quake victims remained in the small Madison Valley Hospital for some time after the earthquake. I remember a boy, a tall and husky football player, about 17 years of age, whose leg had been badly crushed. The Bozeman doctors wanted to amputate his leg, but Doc Losee, who received extra training as an orthopedist just before the quake, insisted he could save the limb. The boy was walking when I last saw him and I believe he did heal under Doc Losee’s care.

Our father, Wayne Robison, was among the early rescuers at the earth slide scene and he is pictured in the book, The Day the Mountain Fell. The Robison ranch, the Green acre, was on the other side of the valley and none of our family had felt the quake with the intensity that we felt it. They related that they were driving home from a movie in Ennis and they felt the car lurch to one side about the time of the earthquake, but thought nothing of it.

The family ranch had a grazing permit just a few miles from the epicenter of the quake in an area called Antelope Basin. A pipeline from Hidden Lake took water from the lake up a steep mile long hill for the cattle on the reserve. When they went up to check the pipeline, it was laying broken in pieces like a bunch of spaghetti straws.

With the river at such a low level, many of the famous Madison Valley trout were stranded in small pools of water. Don, Jim and my father did some fishing with their hands and came home with a good mess of fish for dinner. Jim had the luckiest catch of the day, a 2 and one half foot rainbow trout.

source:
[h/t SMc]
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A Force of Nature — Hebgen Lake Earthquake

On August 17, 1959, one of nature’s most powerful forces was unleashed in the Madison Canyon, just outside the border of Yellowstone National Park. The canyon was packed with people, cars, tents, and trailers. At just before midnight a massive earthquake shook the canyon and in a few seconds, changed the land and the people forever. The Madison River Canyon Earthquake area provides a vivid reminder of how the landscape and the people were suddenly changed on that August night. This video tells the story of the Hebgen Lake Earthquake.

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Madison Canyon Landslide (1959)

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1983 Borah Peak earthquake

The 1983 Borah Peak earthquake occurred on October 28, at 8:06:09 a.m. MDT in the western United States, in the Lost River Range at Borah Peak in Central Idaho.

The shock measured 6.9 on the moment magnitude scale and had a maximum Mercalli intensity of IX (Violent). It was the most violent earthquake in the lower 48 states in over 24 years, since the 1959 Hebgen Lake earthquake in nearby southwestern Montana.

continued: Wikipedia
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The Borah Peak Earthquake on October 28, 1983

January 21, 2010 by Arne

On the 25th anniversary of this little-remembered quake in Idaho’s wilderness, the Lewiston Morning Tribune‘s Casey Santee explained that it “rocked Mackay and the nearby town of Challis, resulting in two deaths and millions of dollars in property damage. It was one of the most powerful temblors to strike North America during the 20th century, measuring 7.3 on the Richter scale.

“People felt the Earth move throughout Idaho and in surrounding states that day. It caused the valley to sink about 5 feet, and Mount Borah – Idaho’s highest peak – to grow by a foot and a half.”

Pretty much all of the below accounts from the Borah Peak quake come from articles transcribed and provided on the University of Utah’s Seismograph Stations’ site, which is at (link) The site has plenty of information about seismicity in the Intermountain Seismic Belt, including Utah and Idaho.

link: to continue reading The Borah Peak Earthquake on October 28 1983
(Note this article has many interesting stories)
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Borah Peak, Idaho 1983 October 28 14:06 UTC Magnitude 6.9

Largest Earthquake in Idaho

The Borah Peak earthquake is the largest ever recorded in Idaho – both in terms of magnitude and in amount of property damage. It caused two deaths in Challis, about 200 kilometers northeast of Boise, and an estimated $12.5 million in damage in the Challis-Mackay area. A maximum MM intensity IX was assigned to this earthquake on the basis of surface faulting. Vibrational damage to structure was assigned intensities in the VI to VII range.

Spectacular surface faulting was associated with this earthquake – a 34-kilometer-long northwest-trending zone of fresh scarps and ground breakage on the southwest slope of the Lost River Range. The most extensive breakage occurred along the 8-kilometer zone between West Spring and Cedar Creek. Here, the ground surface was shattered into randomly tilted blocks several meters in width. The ground breakage was as wide as 100 meters and commonly had four to eight en echelon scarps as high as 1-2 meters. The throw on the faulting ranged from less than 50 centimeters on the southern-most section to 2.7 meters south of Rock Creek at the western base of Borah Peak.

Other geologic effects included rockfalls and landslides on the steep slopes of the Lost River Range, water fountains and sand boils near the geologic feature of Chilly Buttes and the Mackay Reservoir, increase or decrease in flow of water in springs, and fluctuations in well water levels. A temporary lake was formed by the rising water table south of Dickey.

The most severe property damage occurred in the towns of Challis and Mackay, where 11 commercial buildings and 39 private houses sustained major damage and 200 houses sustained minor to moderate damage.

At Mackay, about 80 kilometers southeast of Challis, most of the commercial structures on Main Street were damaged to some extent; building inspectors condemned eight of them. Damaged buildings were mainly of masonry construction, including brick, concrete block, or stone. Visible damage consisted of severe cracking or partial collapse of exterior walls, cracking of interior walls, and separation of ceilings and walls at connecting corners. About 90 percent of the residential chimneys were cracked, twisted, or collapsed.

At Challis, less damage to buildings and chimneys was sustained, but two structures were damaged extensively: the Challis High School and a vacant concrete-block building (100 years old) on Main Street. Many aftershocks occurred through 1983. Also felt in parts in Montana, Nevada, Oregon, Utah, Washington, Wyoming, and in the Provinces of Alberta, British Columbia, and Saskatchewan, Canada.

source: USGS – more info
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1983 earthquake

by Rick Just

Today, October 19, is the Great Idaho Shakeout. Schools, businesses, and families all over the state will be participating in earthquake drills. Idaho is the fifth most seismically active state in the nation. Do you remember the last big quake in the state, the Borah Peak earthquake of October 28, 1983?

I was in Boise and remember feeling the earth move in waves. I worked at a radio station then and recall getting a call from a sister station in Portland to see how we were doing. They’d heard Boise had been flattened. There wasn’t much damage here, but few know how close we came to a major collapse at Boise City Hall. One of the big cement girders holding up the second floor vibrated within about a half an inch from slipping off its support. Rest assured, city workers, they fixed that little issue.

Challis and Mackay were near the epicenter, so the major damage of the quake, which measured 6.9 on the Richter Scale, occurred there. Two children on their way to school in Challis were killed by the falling false front of a building. More than $12 million in damage occurred in the area. A friend of mine, Georgia Smith, was living in Challis at the time and was unhurt, but startled to see a boulder the size of Volkswagen sitting anew in her front yard (Idaho Statesman front page).

You can still clearly see the scarp, or surface fault for miles along the western slope of the Lost River Range below Mount Borah south of Challis and north of Mackay. The summit of Mount Borah rose about 6 inches, while the valley below dropped about 9 feet.

Speaking of Idaho history posts are copyright © 2017 by Rick Just.

1983ChallisQuakeJust-a
(link to larger zoomable size)

source: Speaking of Idaho, Rick Just (FB)
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