Jan. 23, 2019 Shoshone Lake/Lewis Lake Swarm

The video directly above is of the spectrogram stream for station YDD for the main burst of seismicity that occurred between Shoshone Lake and Lewis Lake at Yellowstone on January 23, 2019. This swarm was another rapid fire swarm, most of which usually occur near West Thumb Lake or Yellowstone Lake. Please CLICK HERE to see my page dedicated to the rapid fire swarms that occur in and around West Thumb Lake and Yellowstone Lake. It contains ALOT of data and info but the best swarms are highlighted! To view the data and info regarding the January 23, 2019 rapid fire swarm near Shoshone Lake and Lewis Lake, please click the title of this post or "read more".

The image directly above shows the location of the swarm area in regards to 3 of the closest working seismic stations. Now as you will see below, only 5 earthquakes were reported for this swarm even though the data shows many more actually occurred. Also below you will notice I have the severity level set to moderate. If you wish to understand what the severity level is, I explain it on this page here: West Thumb Rapid Fire Swarms

I won't be able to show every single event via the plot images below, however I will try my best! Also the estimated earthquake counts are calculated by comparing P wave arrivals on surrounding stations using the program WAVES.

Start of first minor burst: 1:23UTC
End of first minor burst: 1:31UTC
Estimated EQ count for first minor burst: 28

Start of second minor burst: 3:17UTC
End of second minor burst: 3:22UTC
Estimated EQ count for second minor burst: 13

Start of main burst swarm: 9:58UTC
End of main burst swarm: 10:21UTC
Estimated EQ count for main burst: 50

Total earthquake count (includes even the tiniest events; all 3 bursts in seismicity): ~91
Reported count: 5 (reported earthquakes ONLY for the main burst; the 2 minor bursts prior were not reported)
Largest reported earthquake of this swarm: M3.0 at 9.4km Depth
Largest amplitude: ~208,600 (YDD), ~59,000 (B944)
USGS EQ map for this swarm: CLICK HERE
Severity: Moderate


First I will show the helicorder charts, also sometimes called webicorders, and then I will show the USGS event page and 3-plot image of the largest earthquake of this swarm. Remember to always pay attention to chart labels and any captions beneath any images.

Also, notice how Shoshone Lake and Lewis Lake is a weird location for a swarm? Well the last time this location saw any type of moderate-major seismicity was November 25, 2016! So it has happened here before, but why? Please CLICK HERE to view the swarm that struck Shoshone Lake on November 25, 2016!

USGS event page for the largest earthquake to occur during this swarm.

A seismogram, spectrogram, and spectra plot of the largest event, all on one image. This image can also be found in one of the last 2 slideshows of this post. This, and all other 3-plot images, were generated by myself using the seismic program SWARM and data obtained from seismic station YDD.

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Now I will quickly show the first burst of seismicity on January 23, 2019. No earthquakes were reported for the first and second bursts, however according to P wave arrivals it does appear to be occurring near the swarm location. Possibly some type of precursor to the main burst? I don't know. I will first show an image of the whole first burst and then show individual plots of most of the events within this burst. I will use slideshow format for the "in depth" images.

Now I will show the second burst of seismicity which only lasted about 5 minutes and contained 13 micro-quakes. No slideshows for this one, only 3 images. And again, no earthquakes were reported for this burst.

Below I will show the main burst of seismicity, which contained the strongest events and the highest quantity as well. This main burst contained about 50 earthquakes, with only 5 being reported, during a time period of approximately 23 minutes. Although the count is low, so is the time frame! This again is characterized as a rapid fire swarm with 2 precursor micro-swarms. I will first show a 3-plot image detailing most of the events within the main burst. Then I will show the slideshow containing 11 3-plot images. I did not capture all of the events, but most of them I did!

If there were any mistakes in this post, please comment below or shoot me an email. Also remember to pay attention to chart labels first and any captions beneath any images!