Strong Earthquake Rocks Central Idaho [otd 7/12]

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.

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.