 In this post I am going to discuss and show the details of an extremely peculiar rapid-fire earthquake swarm that just recently struck north of Green River in southwest Wyoming. This earthquake swarm was a rapid fire swarm, kind of like the ones seen from time to time near West Thumb Lake and Yellowstone Lake at Yellowstone, and is one of the craziest and coolest swarms I have ever had the chance to analyze. However a big difference is that this swarm, with magnitudes reaching around 3.0-3.2, contained many low frequency earthquakes. Sometimes the low frequency events were happening in such close proximity that they blended to create a type of low frequency tremor, which is what volcanic tremor is theorized to be made of. It is highly peculiar this type of earthquake swarm, with these magnitudes and this amount of energy, would even dare to strike in SW Wyoming. This was for sure a strange one and this post will detail as much as possible. Please click the title of this post or "read more" to continue, if you have not done so already. If you would rather watch this as a video, please watch the video below. If you wish to skip to a part you want, please CLICK HERE to visit the video on my YouTube channel.  Around noon Mountain Time on February 22, 2019, an extremely energetic and peculiar earthquake swarm struck just to the northwest of Green River in the southwestern section of Wyoming. This location is an extremely strange location for an earthquake swarm, especially a rapid fire swarm such as this one. This earthquake swarm is for sure one of the craziest and coolest earthquake swarms I have ever analyzed (at least so far), well except for the 2008-2009 dike intrusion of Yellowstone Lake. In the image directly above you can see the location of the earthquake swarm in regards to 4 of the closest seismic stations. As you will see within the plots below, this earthquake swarm contained mainly low frequency earthquakes with some of them occurring so fast that it sometimes blended to create a tremor-like event. This was a rapid fire swarm, much like the ones seen around West Thumb Lake and Yellowstone Lake from time to time (CLICK HERE). This also contained many low frequency events that appeared to have very similar characteristics to the possible magma resonance spotted during the 2008-2009 dike intrusion of Yellowstone Lake (CLICK HERE; scroll down to possible magma resonance). Also, please note that the depths of the earthquakes are likely to be extremely wrong. Now why is that? I highly doubt the depths are correct. One of the events reportedly struck at -3.3km in depth, which would be approximately 10,826 feet above sea level. However if you check on Google Earth, the elevation where the epicenters are is about 6,400 feet above sea level. That means, if correct, these events transpired 4,400 feet above the surface of the earth? That is not possible. Plus, as you are about to see in a second, these events even traveled hundreds of miles showing up on seismic stations in Yellowstone Caldera and other areas as well so we know for a fact these events did strike underground somewhere. Sadly, I don’t think the depths will ever be accurately constrained since these were the wackiest low frequency events ever! Also, there were many, many more of these strange low frequency earthquakes after the time period allotted in the description and plots below. It is entirely possible this strange swarm is still continuing, but in a diminished form. However since this happened this fast, it is likely this will happen again. I am currently contacting professionals to see what their take on this event was. I personally believe this was NOT tectonic, hydrothermal, or mine activity. That is due to the characteristics of the waveforms and the strength of the events compared to how fast they occurred. Now you will notice many of the events occurred in extremely rapid succession. In the plots below, it is almost impossible to view only one event due to how many are occurring. The energy of this swarm was impressive for the types of earthquakes that made up the swarm. Overall, this was a good sized low frequency earthquake swarm with possibly some VLF events thrown in the mix. This swarm occurred on February 22, 2019 and info about this swarm is shown below: -February 22, 2019 SW Wyoming swarm: Start of swarm: 19:51UTC End of swarm: 20:58UTC Note: Although I have the time period of the swarm stated directly above, there were many more events after the main burst in seismicity. This swarm was extremely peculiar. In regards to its energy and how often the events transpire, it is similar to the rapid fire swarms seen around West Thumb Lake and Yellowstone Lake from time to time. Even though this earthquake swarm did contain some events with higher frequencies, most are still considered low frequency earthquakes. Also, some of the events that seem to be tremor may be multiple events occurring in such rapid succession you cannot tell them apart. The total estimated earthquake count below only counts the events within the time period stated above. Total earthquake count (includes even the tiniest events): ~85 (if many of these were earthquakes, it is likely this number is somewhat higher for the time period above) Reported count: 6 so far Largest amplitude from closest station: 169,170 (GAWY-HHZ) USGS EQ map of this swarm: CLICK HERE Below I will first show 5 helicorder charts. 4 of them will be from the 4 closest seismic stations and the last one will be from MCID at Yellowstone which picked up these events quite well. The chance that any of these were occurring at or above the surface is basically 0 now. After that I will show some random images and then I will show the USGS event pages to 2 select events, along with their custom plots I made. Then I will detail much of the swarm from the time period stated above. I will not be able to show every single event, but I will show alot of them! Remember to always read chart labels first and any captions beneath any images.  A custom 3-plot image detailing the most energetic portion of the 2019/02/22 rapid fire swarm in SW Wyoming.  Here is a 3-plot image detailing how many of the earthquakes in the swarm were strong enough to be detected quite well on MCID, and other stations, at Yellowstone Caldera. This was an insane swarm! Not because of the magnitudes or energy, but because of their characteristics!  The data stream from 5 seismic stations, 4 being the ones closest to the swarm and MCID being the station from Yellowstone. Again, this was the most active part of the swarm but many low frequency earthquakes still continued long after this time period.  Some more seismograms of a random part of the swarm, via the program WAVES.  USGS event page to the largest reported earthquake of this low frequency rapid-fire swarm. Remember, the depths are all likely to be incorrect.  The USGS ShakeMap, showing what humans could have felt, for the M3.0 low frequency earthquake.  A 3-plot image, generated by myself, for the largest reported event of the swarm. Note the crazy low frequency characteristics for how strong it was! Again, some of these events were eerily reminiscent of the ones seen on December 29, 2008 during the 2008-2009 dike intrusion of Yellowstone Lake.  USGS event page for one of the events that reportedly was felt by 1 person.  Below I will detail alot of the low frequency earthquake swarm via the 3-plot images I like to generate. I will show them in slideshow format. The first slideshow contains 13 of these images, so does the 2nd slideshow. So, what do you think this swarm was caused by? Let me know! An additional note, it seems there was an interesting increase in SO2 emissions basically in the same area as the swarm, just as the swarm was peaking/calming. Check it out (CLICK HERE to visit video on YouTube):
10 Comments
Mary Wright
2/23/2019 03:41:30 am
I believe it is magma on the move To me it is similar to waves on the ocean. Standing waves frequenly are shown like that I agree it's not tectonic or hydrothermal. Since the north poles are split and moving the effects of the sun to earth electromagnetic connection is having a stronger effect than normal that's why we are experiencing more earthquakes and volcanic events
Ben
2/24/2019 01:42:21 pm
That very well could be. And you are right, definitely not hydrothermal or tectonic. Even mining activity doesn't look like this. I don't like calling it magma on the move though. It is too broad of a statement. I am thinking this is some type of intrusion event from a tiny local chamber. However even that doesn't make much sense.
Jason
2/23/2019 08:19:53 am
It appears this swarm occurred very close to an area of soda ash mines on the Green River formation. If I’m not mistaken these mines are underground and utilize the roof and pillar method similarly used in underground coal mines. I have zero experience in interpreting seismic data but it’s a good chance that these may indicate a collapse event rather than some sort of magmatic intrusion. It’s highly unlikely any sort of hydro or magma intrusion would suddenly show up so shallow without having ever been detected moving up from deeper.
Ben
2/24/2019 01:37:55 pm
Hey Jason. That is possible it was some type of hour long collapse event, but the waveforms are off. It does look somewhat similar to a long drawn out mining incident, however check out the "Exotic Events" page in the seismic events drop down menu here on my website. I do have some examples.
John F Kellmer
2/24/2019 09:47:38 pm
Hi Ben
Ben
2/24/2019 10:29:34 pm
Well the depths on these events were definitely wrong so I do think you could be right. I am thinking these events are much deeper than they state, even so because they traveled hundreds of miles in a short period of time.
Ben
2/26/2019 11:44:54 am
That could be! However frequencies were a little bit too low. Maybe a mix of processes? Cool stuff. God bless!
Paul Haugan
2/25/2019 10:21:22 pm
Ben..some more thoughts on my suggestion that this was a gas event. This based on my knowledge of pipe organs and my love of music. Pipe organs are powered by air pressure. An 8 foot pipe resonates at 440 hz, middle C. One octave below is a 16 foot pipe at 220 hz. To get to 1 hz would take a large long chamber like a volcanic vent. Pressure variation will change volume, but not hz. Octaves are in phase (divisible onto one and the other) and don’t interfere. Notes that are out of phase cause beat notes,alternately canceling and reinforcing. Using a pipe organ as a model and taking into account the SO2 most of the wave form can be explained. The high frequency is rock fracture allowing gas release. I witnessed a similar event in New Zealand, North Island near Rotorua. It has a valley floor that has active geothermal activity. It reminded me of parts of Yellowstone. I was having breakfast at a diner a few miles away on the north shore of Lake Rotorua. The building started to shake at around 1hz. The intensity changed, but not the hz. This continued for a couple of minutes and sometimes splashed coffee out of my coffee cup. The waitress said the diner was over a volcanic vent and there would be an ash plume at White Island Volcano in 18-20 hours. White Island is about 20 miles off the the northeast coast of New Zealand’s north island. The waitress was correct, saw a video of it on the news.
Ben
2/26/2019 11:47:42 am
Thank you for the additional thoughts! That really sounds like the most likely possibility now. You did a really good job explaining it! And OH MY GOD! she just said "OH yeah, we get that all the time, There is a volcanic vent beneath us" and moved on with her day? Haha shes got some guts to work there!!! Pretty cool. Thanks again! Leave a Reply. |
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This blog page is solely for interesting earthquake swarms that occur in locations other than the ones I already have posted. Pretty much any earthquake swarm I am interested in, that cannot be placed on other pages, will be placed here. Please click the title of each post or "read more" to view each swarm. Archives
October 2019
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