I really liked the comparison of the Idaho and Utah quakes. I binge watched today and finished all your videos. Thank you. I’m really enjoying my geological education.
I felt the quake in Boise. Had been through some smaller quakes in E. OR and SoCalia. The 2000 quake in SE Boise was terrifying. When it first started there was a grinding sound so loud I thought the National Guard was driving a tank down my street. Then it sounded like the shingles on my house were going to be ripped off. By the time I got under a doorway, there was an awful roar unlike anything I have ever heard. It sounded like a gigantic train was coming down Broadway Ave. Never ever experienced anything like this before. It left me shaking. Others in the Boise area didn't experience anything like this.
Tensor Moment Diag: Thanks, that was best vid explanation for a very complicated math geolocy exercise. Still don't quite understand how you can figure LH or RH lateral...need to rewatch this.
Quite interesting! I didn't know ID was the 6th most active. I am assuming my state California is the most lol. I'm in Eureka next to the tri-plate area so we constantly get like 2- 4.0 quakes off the coast. I can sometimes feel the 4.0 quakes and I always feel the 5+ quakes. We've had some 6+ but those were not close to my town. A town closer had damages though. Question, I thought all mountains were from subduction like India and the Himalayas. So I thought a mass must of subducted to make the rockies and then another to make the cascades/sierra nevada's. I thought the intermountain was raised due to lava extrusion. How much of the western mountains are formed by the animation you showed that looked like subsidence in one area? Also, why does the pacific plate moving away cause stress on the north American plate? Wouldn't lava bubble up taking the place between the two? Great videos and I'll keep looking around for answers!
Actually, California is second with Alaska first. Mountains can be formed by volcanic processes (Cascades), subduction (Andes), and even extension (Basin and Range). The Pacific Plate is not moving away from North America in a perpendicular manner. Rather it is moving obliquely, creating both strike-slip faults (San Andreas) and areas of extension (Basin and Range). There are other models to account for the extension. This is just one.
Hi Randall. Good question. Aquifers are very rarely (almost never) similar to an underground lake. Instead, aquifers are rocks or sediments with water in the cracks and pore spaces. Basically, its mostly rock material with water filling in whatever spaces are available. The bigger factor in seismic wave propagation is what kind of rock or sediment is present. It is also worth noting that areas with water-saturated sediment (where the water table is high) often amplify seismic waves, making the shaking more severe. Hope this makes sense and helps.
@@shawnwillsey Interesting. I had noticed a trend in that several friends and family who live north of the Rathdrum Prarie in Northern Idaho said they did not feel the quake, but those south of it did. The aquifer in that area came to mind immediately as unique to that area and between those that did and did not feel it.
Thank you for the fantastic explanation. Where can I find the published geologic map you used? I attempted to look it up on USGS, but couldn't filter my results to what you showed?Also, interestingly enough, I was out on the snow, skinning up Shaffer Butte when the earthquake occurred, but did not feel a thing, nor did I notice any cracking. Not sure if that was a result of being in motion when the quake happened, the storm intensity (wind), or perhaps that snow is also "in motion" while it is falling and accumulating. I'm not sure if the snowpack has an attenuating quality about it that makes seismic waves dampened?
Hi Ryan. The geologic map I showed is from the Idaho Geological Survey Interactive Map. Go to the epicentral area and click on IGS Maps. This will bring up all available maps for that area. The epicenter of the Mar 31 quake is on the Geologic Map of the Deadwood River 30X60 Minute Quadrangle: www.idahogeology.org/product/GM-45 Once you are there, click on download map from the column on the right. The fact that you didn't feel the quake is probably due to several factors: (1) you were moving. I was pushing a couch across the room the moment it struck and also didn't feel it. (2) you were outside where you were less likely to notice things swaying or shaking. Also, houses and structures transmit seismic energy differently such that it is usually easier to "feel" a quake indoors vs outdoors. Stay curious!
I live in Boise, and my apartment (upstairs) was very active during the big earthquake. I still feel most all the aftershocks that are over 3.3. Can you say if it is just the apartment, or is there a direct line that goes here (fault continuation). I'm right next to the foothills if that makes a difference.
Definitely not a continuation of this fault system. Could be the rocks or material under your home are able to transmit seismic energy more efficiently or it could be the style and materials of the building. Great question.
Hi Tad. No, these aftershocks are not at all related to any volcanic activity. First, there are no volcanoes in the area. Second, this was an earthquake created by tectonic stresses within a known seismic zone. The number, frequency, and location of aftershocks at this point is totally expected and is considered normal. These aftershocks should diminish in frequency and size over the next few weeks and months.
Shawn, thank you for posting this information. Last autumn I was photographing the mountains near Custer, and I discovered a large molybdenum mine at Thompson Creek which I believe is still active. A geologic disturbance would drain these tailings into the Salmon River. Should citizens be concerned? Thanks again for sharing this video.
Hi Matt. Good question and I don't have a solid answer. I am not sure that it is a given that the earthquake disrupted this situation at Thompson Creek. It might be a question for the Idaho Dept of Environmental Quality. Let me know if they respond.
I really liked the comparison of the Idaho and Utah quakes. I binge watched today and finished all your videos. Thank you. I’m really enjoying my geological education.
Fantastic video! Always good to learn to learn things from local experts. You're awesome Shawn!
Thanks for your kind words. Lots of videos still to come so please share with others.
I felt the quake in Boise. Had been through some smaller quakes in E. OR and SoCalia.
The 2000 quake in SE Boise was terrifying.
When it first started there was a grinding sound so loud I thought the National Guard was driving a tank down my street.
Then it sounded like the shingles on my house were going to be ripped off.
By the time I got under a doorway, there was an awful roar unlike anything I have ever heard.
It sounded like a gigantic train was coming down Broadway Ave.
Never ever experienced anything like this before.
It left me shaking.
Others in the Boise area didn't experience anything like this.
Thanks for explaining the "beach ball" symbols.
You bet!
Thank you so much for taking the time to providing this information - very educational!
You bet. I love to share what I know with others. Please subscribe and share my channel with others who may want to learn.
Wonderful explanation of the relationship between the UT and ID earthquakes. I will be referring my students to this video.
Awesome. Thanks for watching this.
I didn't mean to watch the whole thing, no worries you got us. Good work. New sub. That quake was intense where I was at!!!
Hey thanks for watching and learning with me. Enjoy the other videos and look for more soon.
The earthquake in SLC was quite unnerving.
Tensor Moment Diag: Thanks, that was best vid explanation for a very complicated math geolocy exercise. Still don't quite understand how you can figure LH or RH lateral...need to rewatch this.
Quite interesting! I didn't know ID was the 6th most active. I am assuming my state California is the most lol. I'm in Eureka next to the tri-plate area so we constantly get like 2- 4.0 quakes off the coast. I can sometimes feel the 4.0 quakes and I always feel the 5+ quakes. We've had some 6+ but those were not close to my town. A town closer had damages though.
Question, I thought all mountains were from subduction like India and the Himalayas. So I thought a mass must of subducted to make the rockies and then another to make the cascades/sierra nevada's. I thought the intermountain was raised due to lava extrusion. How much of the western mountains are formed by the animation you showed that looked like subsidence in one area? Also, why does the pacific plate moving away cause stress on the north American plate? Wouldn't lava bubble up taking the place between the two?
Great videos and I'll keep looking around for answers!
Actually, California is second with Alaska first. Mountains can be formed by volcanic processes (Cascades), subduction (Andes), and even extension (Basin and Range). The Pacific Plate is not moving away from North America in a perpendicular manner. Rather it is moving obliquely, creating both strike-slip faults (San Andreas) and areas of extension (Basin and Range). There are other models to account for the extension. This is just one.
Shawn, a question. Can an underground aquifer act as a dampener for earthquake waves?
Hi Randall. Good question. Aquifers are very rarely (almost never) similar to an underground lake. Instead, aquifers are rocks or sediments with water in the cracks and pore spaces. Basically, its mostly rock material with water filling in whatever spaces are available. The bigger factor in seismic wave propagation is what kind of rock or sediment is present. It is also worth noting that areas with water-saturated sediment (where the water table is high) often amplify seismic waves, making the shaking more severe. Hope this makes sense and helps.
@@shawnwillsey Interesting. I had noticed a trend in that several friends and family who live north of the Rathdrum Prarie in Northern Idaho said they did not feel the quake, but those south of it did. The aquifer in that area came to mind immediately as unique to that area and between those that did and did not feel it.
Thank you for the fantastic explanation. Where can I find the published geologic map you used? I attempted to look it up on USGS, but couldn't filter my results to what you showed?Also, interestingly enough, I was out on the snow, skinning up Shaffer Butte when the earthquake occurred, but did not feel a thing, nor did I notice any cracking. Not sure if that was a result of being in motion when the quake happened, the storm intensity (wind), or perhaps that snow is also "in motion" while it is falling and accumulating. I'm not sure if the snowpack has an attenuating quality about it that makes seismic waves dampened?
Hi Ryan. The geologic map I showed is from the Idaho Geological Survey Interactive Map. Go to the epicentral area and click on IGS Maps. This will bring up all available maps for that area. The epicenter of the Mar 31 quake is on the Geologic Map of the Deadwood River 30X60 Minute Quadrangle: www.idahogeology.org/product/GM-45 Once you are there, click on download map from the column on the right.
The fact that you didn't feel the quake is probably due to several factors: (1) you were moving. I was pushing a couch across the room the moment it struck and also didn't feel it. (2) you were outside where you were less likely to notice things swaying or shaking. Also, houses and structures transmit seismic energy differently such that it is usually easier to "feel" a quake indoors vs outdoors. Stay curious!
I live in Boise, and my apartment (upstairs) was very active during the big earthquake. I still feel most all the aftershocks that are over 3.3. Can you say if it is just the apartment, or is there a direct line that goes here (fault continuation). I'm right next to the foothills if that makes a difference.
Definitely not a continuation of this fault system. Could be the rocks or material under your home are able to transmit seismic energy more efficiently or it could be the style and materials of the building. Great question.
2 weeks later the quakes are still rocking do you think these earthquakes can be tied to a volcano ?
Hi Tad. No, these aftershocks are not at all related to any volcanic activity. First, there are no volcanoes in the area. Second, this was an earthquake created by tectonic stresses within a known seismic zone. The number, frequency, and location of aftershocks at this point is totally expected and is considered normal. These aftershocks should diminish in frequency and size over the next few weeks and months.
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Shawn, thank you for posting this information. Last autumn I was photographing the mountains near Custer, and I discovered a large molybdenum mine at Thompson Creek which I believe is still active. A geologic disturbance would drain these tailings into the Salmon River. Should citizens be concerned? Thanks again for sharing this video.
Hi Matt. Good question and I don't have a solid answer. I am not sure that it is a given that the earthquake disrupted this situation at Thompson Creek. It might be a question for the Idaho Dept of Environmental Quality. Let me know if they respond.