February 7, 2019 Swarm Strikes East of L.A. in Cali! Right next to Pisgah Crater and Lavic Volcanic Field!
Welcome to the first post on another new page just recently added to my website! This first post will deal with a very energetic, rapid fire swarm that struck east of Los Angeles on February 7, 2019. This swarm seems to be similar to the ones seen at West Thumb Lake in Yellowstone from time to time (CLICK HERE for that). This swarm also occurred very close to Lavic Volcanic Field and the Pisgah Cinder Cone. As usual, please click the title of this post or "read more" to continue...
First off, the image first posted (in the intro) shows the location and some information about Lavic Lake Volcanic Field. You can see I also marked where the swarm occurred. The image directly above shows the location of the earthquake swarm in regards to the 2 closest seismic stations and the Pisgah Crater Volcano (cinder cone). This whole area still is potentially volcanic and most likely will see another eruption someday. However it is likely the eruptions in this area will be of traditional lava flows. Although tephra and ash have the possibility of being ejected, lava effusion is the most likely outcome.
The data and info in this post pertains to the events that transpired just to the east of Pisgah Crater in California from 00:00UTC February 7, 2019 to 5:26UTC February 8, 2019. The swarm saw 63 reported earthquakes during the time period just stated. A few others occurred after this time period, but it seems the swarm is calming. However another update will be issued if another swarm occurs in this area.
Now this swarm in question occurred just east of the Pisgah Cinder Cone and Lavic Lake Volcanic Field (intro image). Please CLICK HERE if you wish to learn more about Lavic Lake and CLICK HERE to learn more about specifically Pisgah Cinder Cone. Also, please CLICK HERE if you wish to visit the USGS EQ map detailing all reported events that occurred within the location and time period stated above.
This interesting earthquake swarm carried a good amount of energy and can be characterized, during many moments, to be a rapid fire swarm, much like what is seen around West Thumb Lake at Yellowstone from time to time. This rapid fire swarm seems to be more within the lines of a small intrusion of magma, but do not hold me to that. It is possible this was tectonic, but the characteristics of the swarm, including how fast the events occurred, point out that this was most likely some type of rock breaking event. Of course hydrothermal activity could do this as well, however magma is a more likely culprit for this area (as is tectonic activity).
First, there was a small burst in seismicity lasting 4 minutes that contained 4 micro-quakes at about 1:04UTC Feb. 7. Then another episode of seismicity occurred from 7:16UTC to 9:55UTC on Feb 7 that included a total of approximately 55 earthquakes. Then, the main burst of seismicity started at about 14:16UTC and lasted until 20:44UTC, on Feb 7 as well. The total for the main burst, including events too small to be reported, was around 190 earthquakes of all sizes. The rest of the seismicity from 20:44UTC Feb 7 to 5:26UTC Feb 8 contained around 80 earthquakes of all sizes. Many of the events occurred in pairs and episodes, instead of stretched out over a period of time. Again, this earthquake swarm is categorized as a rapid fire swarm.
Altogether, for the entire time period stated at the beginning of this post, approximately 329 earthquakes occurred with only 63 of them being reported! Many were most likely not reported due to the lack of strong amplitudes and the lack of a dense seismic array of stations. The estimation above may be off just a tad, I wouldn't be surprised, but it is pretty close! Again I used data from surrounding stations in the program WAVES to cross correlate P wave arrivals.
Below I will show alot of data in regards to this swarm. I will first show the helicorders for the 2 closest seismic stations and will put them in slideshow format: NBS and RAG, both in the CI network within the SCEDC database. Then I will show the USGS event page and 3-plot image of the largest earthquake within the swarm. Afterwards I will show a strange low frequency event, the 3-plot images to the fastest parts of the swarm, and the rest of the seismic plots will be shown in slideshow format (in 2 slideshows) at the bottom of the post. Remember I am not able to show you ever single event within the plots below. However I will try my best to show most of them! The last 2 slideshows at the bottom of the post contain 24 3-plot images.
Remember to always pay attention to chart labels and any captions beneath any images!
Now this event caught my eye right off the bat! This event was labeled by USGS as a M1.9 "Quarry Blast". I admit it looks similar, and just might be a quarry blast, however the fact that this occurred right during this swarm and carries the same characteristics as a low frequency earthquake has me thinking.......... Maybe this was a low frequency earthquake! Who knows. However it is my solid belief the swarm of February 7, 2019 was not tectonic in nature. So it wouldn't be that much of a stretch!
This was the last major burst of seismicity for this swarm, at least for the time period stated in the beginning of this post. Within this 3-plot image and the one just previously shown, you can find some of these events within the 3-plot image slideshow below. Just remember to pay attentiont to the times! All are in UTC! This was definitely a very intriguing swarm! And one we see from time to time at Yellowstone.
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.