M2.9 – 7km E of Challis, Idaho
- 2015-09-18 02:02:00 (UTC)
- 2015-09-17 18:02:00 (UTC-08:00) in your timezone
- Times in other timezones
- 7km (4mi) E of Challis, Idaho
- 192km (119mi) ENE of Boise, Idaho
- 194km (121mi) ENE of Garden City, Idaho
- 196km (122mi) NE of Mountain Home, Idaho
- 198km (123mi) ENE of Eagle, Idaho
M2.8 – 26km W of Challis, Idaho
- 2015-09-21 13:18:42 (UTC)
- 2015-09-21 05:18:42 (UTC-08:00) in your timezone
- Times in other timezones
- 26km (16mi) W of Challis, Idaho
- 167km (104mi) NE of Boise, Idaho
- 168km (104mi) NE of Garden City, Idaho
- 171km (106mi) NE of Eagle, Idaho
- 179km (111mi) NE of Meridian, Idaho
USGS Caught Deleting Yellowstone Seismic Events, Hiding Any Major Quake Activity
M2.9 – 7km E of Challis, Idaho Time 2015-09-18 02:02:00 (UTC) 2015-09-17 18:02:00 (UTC-08:00) in your timezone Times in other timezones Nearby Cities 7km (4mi) E of Challis, Idaho 192km (119mi) ENE of Boise, Idaho 194km (121mi) ENE of Garden City, Idaho 196km (122mi) NE of Mountain Home, Idaho 198km (123mi) ENE of Eagle, Idaho
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 Sandpoint 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.
“Keep calm and move along.” What does it mean?
It’s been, uh, 18 hours and 20 minutes now that I’ve had that message up on one single page of my site, and the freaking out is in full swing… but that message is only there because of freaking out. This server is on a dual-core 1.6 GHz Compaq Presario with less than a gig of RAM, the server is in my bedroom, and my cable modem is what links it to all those hungry browsers out there. And every time one of the seismograms looks Really Really Colorful, several websites out there (I hesitate to call them “notorious” but…) directly embed huge 200K+ seismograms off of my site directly into their articles when they could instead simply download them themselves, or link to them on the USGS site. This has been happening for more than a decade now, the actual provable real swarms don’t even generate as many page hits, and it’s high time everyone out there got some education in:
How Does I Tell If Quake
This is a very, very, very easy thing for anyone to do, regardless of their knowledge; this lesson is all you’ll need. Go here, the page everyone looks at all the time. That page is for January the 7th, 2004, a day on which there actually were nine earthquakes in Yellowstone, the first one worryingly-large. I want you to notice a few things, please…
There are some signals that start with a sharp vertical edge on the left, slowly diminish over a minute or two, and show up on every single one of the seismograms. Those are legitimate local-to-Yellowstone earthquakes. There was a magnitude 5.0 followed by a 3.7, then a 4.1, then a 4.0.
There are some signals that start all fuzzy and kind of wax and then wane. Those are not legitimate local earthquakes even if they do show up on every seismogram, in which case they’re probably large, distant earthquakes.
There are some signals that only show up on one seismogram. Those are not seismic activity of any kind. If a signal doesn’t show up on (nearly) all of them, it was not an earthquake.
The world did not end on 1/7/04 or at any other time in the ensuing 11 years, 8 months, and 14 days. Anyone who screamed “THIS IS THE END!” at the time was wrong.
With those guidelines in mind, examine the page everyone started freaking out about (this time.) Categorize all the signals you see. There are a couple of obvious, large-ish quakes visible on every seismometer. One of them is a magnitude 3.04, not even as large as all those quakes on 1/7/04. But that’s not what everyone’s freaking out about. They’re freaking out about YMR, YNR, and YHR. Don’t they look dramatic? All those colors, so much activity… so much, in fact, that if it were seismic activity, every single seismogram that day would look just like them, all the way to Madagascar. That is not seismic. It’s noisy data lines, or miscalibrated equipment, or high winds, or lots of trucks driving by, or mating meese, or a Beyonce concert in Denver. It is not earth movement, magma intrusion, or harmonic tremors. We know what those look like; go look up some seismograms taken of Mt. St. Helens erupting. Fascinating stuff… and Yellowstone looks nothing like it. Yet one of the pages linking to those images has the headline “Panic Time Yellowstone Explodes Off The Charts.” It’s doing nothing of the sort. THIS is “exploding off the charts”… but even then, during one of the largest quake swarms ever seen there, it didn’t erupt. It will have to look a lot worse than that before any real geologists really get really worried. Trust me. Really.
So that’s why I wanted everyone to stop freaking out, to just calm down and get on with their lives rather than trying to inject some excitement by choosing to believe the opinions of non-geologists on Youtube or SomeBlogSomewhere.com rather than someone like me who actually knows what they’re talking about, but the message seems only to have inflamed everyone’s fears. So I’ve changed the message to green, to prevent Pavlovian panic responses programmed into apparently the entire human race, but the message is the same. There’s nothing to worry about now. And if you ever see it change back to red, the words will be different too. They’ll say, “Okay, now it’s happening!” It will be impossible to miss for those who know what signs to look for and what signs can be ignored. Anyone who shows you an image like YNR’s up there and claims it’s huge massive cataclysmic earth movement either doesn’t know what to look for, or is only saying it to get people to pay attention to them. (“Lying,” as we scientists call it, or “sensationalism” to the layperson.) If everyone stopped buying into it, my poor web server would be a lot happier.
For further help in interpreting seismograms without being afraid of every squiggle on them, please see this video, which I wish I’d known about earlier.
How Does I Tell If Harmonic Tremor
And while if I still have your attention, let me explain harmonic tremors to you. This is an aspect of seismology that people seem to know the least about. HTs occur when gas or liquid rock goes glugging its way through hollow tubes, usually in the build-up to a volcanic eruption. It’s a bit like playing a didgeridoo, or noisy ancient plumbing. These movements resonate at some given frequency, depending on the size and shape of the tube and viscosity of the medium. They almost never occur at a frequency slower than 1 Hz or more than 30 Hz. Now, the seismograms on this site (or any other) have enough room for 15 minutes of time (900 seconds) across the X axis, and 720 pixels to do it in. That means each pixel is averaging together a whole 1.25 seconds’ worth of data, and that means the fastest peak-to-peak it’s capable of showing is 0.4 Hz… far below harmonic tremors. In short, this means you will never be able to see harmonic tremors on any seismogram, at least the ones at Yellowstone. Now, some of you may be familiar with this seismogram on Wikipedia, which shows harmonic tremors, and say “Aha, look here, Mr. Smarty!” but I’m afraid I must burst your bubble. That seismogram is actual ink-on-paper. Since that method doesn’t use pixels, every sweep of the pen gets drawn, nothing gets averaged into a data blob. Also, its X axis is much more expanded than those of seismogram GIFs. There’s no scale visible, which means it’s not easy to guess, but it looks like the width of that entire image represents about 90 seconds. HTs would absolutely leap off the page at you at that resolution, just as they do in the image. Web seismograms just aren’t capable of it. So don’t listen when someone tries to tell you one of them is showing harmonic tremors. Because it ain’t.
One phenomenon frequently mistaken for HTs is known as “teleseisms.” That means “distant earthquakes” in Greek or Latin or something. This YFT seismogram shows two teleseisms starting at about 22:29 UTC and 00:41 UTC, caused by two earthquakes in the Solomon Islands, a 6.9 at 21:45 UTC and a 6.8 at 23:59 UTC. Yes, it takes teleseisms a long time to get through all that planet, about 42-44 minutes from the Solomons to Yellowstone. Any sensitive-enough seismometer on the planet will pick up a quake bigger than magnitude 5.3 or so, but they’re pretty faint. YFT is set to 125 µV, which is really very sensitive, so they show up there. The YMR seismometer is also set to 125 µV, and sure enough, it shows up there too. You just have to look hard to see it through all the perpetual noise YMR always has. So when you see it, don’t think “harmonic tremors, o noes!” Teleseism frequencies are way, way slower than HTs. That’s why you can see them. (PS: the long green smear at 18:50 UTC was a magnitude 4.8 quake that hit near Las Vegas. Even from that far away, the leading edge looks nice and sharp, like a local quake. See how tricky reading these things can be?)
Thanking you for your desire to learn,
PS: I have no affiliations with anyone when it comes to this site. I wrote it, I host it, I maintain it, I improve it now and then, and nobody else has ever been involved. Anything you see appear on here came out of my mind; I’m not a disinformation relay. I WILL tell everyone who views my site once the signs are at long last getting really bad, but by then, everyone will probably already know. So no more “You’re working for Them!” accusations, please. And besides: everyone’s “working” for Them. If you disagree, you just haven’t felt the chains yet. Carry on.
- Idaho Geological Survey
- Boise State University, Department of Geosciences
- University of Utah Seismograph Stations
- Idaho Bureau of Homeland Security
- Largest Earthquake in Idaho: 1983 October 28, Magnitude 6.9
Borah Peak, Idaho
- Damaging Utah, Wyoming, Idaho and Montana Earthquakes
- Historic Earthquakes in Idaho