This is the monthly volcano report for January 2020. If you already know what this usual intro says, please click the title of this post or “read more” to continue. The reported earthquake counts are taken directly from the U.S.G.S. and are only earthquakes reported, not earthquakes recorded. Regarding earthquake counts, it is likely that the reported earthquake total for a given location and time period, mostly during earthquake swarms, is lower than the actual count of earthquakes, in certain cases sometimes drastically lower. Remember, most earthquake swarms at volcanoes do not lead to eruptions. However, almost every eruption is preceded by some type of earthquake swarming and surface deformation. Therefore, swarms and deformation should always be monitored closely regardless of where you think the activity is headed.
 
The volcanoes I will be doing monthly updates on are Yellowstone Caldera in Wyoming, Long Valley Caldera in California, Newberry Caldera and Mt. Hood in Oregon, Mt. Rainier and Mt. St. Helens in Washington state, and Mt. Shasta and Lassen Peak in California. In this update, we will look at reported seismicity counts. If you wish to see recent deformation for Yellowstone or Long Valley, please head to the “Deformation Updates” page which is updated every 2 months or so.
 
The time period of the reported seismicity counts for this update, derived from the USGS earthquake catalog, is from 00:00UTC January 1, 2020 through 23:59UTC January 31, 2020 and magnitudes are always going to be -1.0 and above so you will see every single earthquake that was reported for this time period. The smallest earthquake ever recorded was a M-1.0 and the largest earthquake ever recorded was a M9.5.

Also, the coordinate box I use for each volcano is exactly the same every month, so you always see the activity that occurred in the same area every month. Regarding the 3-plot seismic images I generate for the largest events, I will always try my best to use the closest seismic station to any given event. I will also add the link to the USGS EQ map showing the locations of reported seismicity for the location and time period in question.

January 2020 is likely the quietest month for seismicity at Yellowstone I have ever seen during my past few years of monitoring volcanoes. There were only 49 reported earthquakes for this month. Of course, as usual, there were probably a few unreported events. Regardless, this was indeed an extremely calm month... Almost too calm...

The largest reported earthquake for Yellowstone National Park during January 2020 was a M2.6 at 10km depth on Jan. 10, 2020 at 22:57UTC. This earthquake, which surprisingly was reportedly felt by one person, struck 69km ENE of Old Faithful Geyser, very near the eastern border of Yellowstone National Park near Little Saddle Mountain and seismic station YPK; a strange location for an earthquake.

Also, there was a M2.1 foreshock which struck at 14.0km depth approximately three hours prior to the M2.6. It struck very close to the epicenter of the M2.6. Both events are shown directly below with the M2.6 shown first:

Steamboat Geyser has continued it's activity throughout 2020. However, date/time spacing of the eruptions have widened, seeing an eruption occurs now every 2 weeks or so. It used to erupt every week, but now it seems activity could be calming. The same thing sort of happened during the winter of 2018-2019 with activity ramping up a few months later. This geyser could end activity without any warning, since it has done so in the 1960s and the 1980s. However, it is my opinion Steamboat Geyser will continue to be active for quite some time. Why is this? Let me know by emailing me at washingtonmagma@yahoo.com or shoot me a message on Facebook (Ben Ferraiuolo).

Below are the plots of the most recent eruption which occurred at 04:07UTC February 2, 2020 (9:07pm Mountain Time, February 1, 2020):

Long Valley Caldera's seismicity continues to calm after the intense seismicity that quickly occurred during the month of September 2019 (CLICK HERE for info and plots of that activity). January 2020 experienced only 350 reported earthquake events. It may sound like a great deal, but this is the lowest seismicity we have seen at Long Valley since June 2019, which saw only 340 reported events.

The largest earthquake to strike Long Valley Caldera during the month of January 2020 was a M2.8 at 4.2km in depth on Jan. 2, 2020 at 07:17UTC. It struck within the south-central section of the caldera, 9km E of Mammoth Lakes, CA. Plots below are of this event. The events were sectioned out on the plots below so you can separate each event, since multiple events occurred within a close time range, including the seismic signature of a regional earthquake which arrived on this just just after the M2.8 was detected.

Two more things:

1. Stay tuned for February 2020's update which will include some information about the M4.4 which struck Long Valley Caldera!

2. There was a small rapid-fire swarm that occurred hours before the M2.8 earthquake, which was the largest quake of January 2020. Plots below are of this quick, but energetic, rapid-fire swarm:

Newberry Caldera in Oregon has been extremely calm, and I mean extremely calm, for many months. It usually experiences a couple earthquakes per month, but January 2020 literally saw no earthquakes at all. In 2017, 2018, and early-2019, seismicity was pretty low for Newberry. However, low frequency earthquakes basically dominated the majority of seismicity of this volcano during that time frame.

I have monitored this area as closely as I could. I can confirm there were basically no seimsic events at all during January 2020.

Mt. Rainier is probably one of the best well-known stratovolcanoes in the United States. It is pristine and I have visited the volcano on multiple occasions in late-2019. If you ever get the chance to hike around Mt. Rainier on a sunny and clear day, visit Sunrise and take the Dege Peak trail. There, once you reach the end of the trail, you can see all of the volcanoes in Washington State, except for Mt. St. Helens.

Mt. Rainier experienced only 19 earthquakes during January 2020. Interesting to note, this is the lowest count of earthquakes for over six months. Last month, however, saw the highest count of earthquakes in over six months. As usual, a little over half of the seismicity occurred to the west of the summit in a north-south trend of seismicity known as the WRSZ (West Rainier Seismic Zone). Most earthquakes that occur in this zone are directly related to tectonic activity, though it is possible fluid migration along this "weak spot" may occur every now and then.

The largest earthquake to strike Mt. Rainier during January 2020 was a M2.1 at 8.2km in depth on Jan. 28, 2020 at 08:17UTC. It struck along the WRSZ. However, the largest earthquake to strike under the volcanic edifice itself was a M1.1 at 1.2km in depth on Jan. 7, 2020 (which is my birthday) at 19:29UTC.

Plots below are of both events, with the M2.1 shown first:

Mt. St. Helens is the most recently active volcano in the USA mainland. It erupted on May 18, 1980 with many more eruptions over the next few years. It then erupted, though in a diminished form, between 2004 and 2008 due to a renewed intrusion of magma. It has since been calm for around 12 years now. Regardless, the resurgent/lava dome does steam from time to time.

I visited this volcano with my daughter three times in 2019. Two of those times, the volcano was actively steaming. Small steam output, but steaming nonetheless. If you wish to see the best footage I have of Mt. St. Helens steaming, then please CLICK HERE.

Mt. St. Helens experienced 15 earthquakes during January 2020 which is the 2nd quietest month we have seen for this volcano for over 6 months. Why are Cascade Range volcanoes acting so quiet?!

The largest quake to strike this infamous volcano was a M1.3 at 7.1km in depth on Jan. 24, 2020 at 08:14UTC. It struck ~7km SW or so of the summit. Plots below are of this event:

Mt. Hood in Oregon remains within background levels of seismicity. Seismic activity has been calm as usual for this volcano, since Mt. Hood only sees a few earthquakes per month. That being said, Mt. Hood jumped beyond background levels during July 2019 when a large swarm broke out with around 150 earthquakes striking in rapid succession in only a few days. Please CLICK HERE if you wish to learn more about that swarm. It was one of the largest swarms Mt. Hood has experienced in many, many decades, possibly the largest since record keeping began for Mt. Hood.

However, sequences between 1997 and 2005 likely produced some very energetic swarms. Regardless, the amount of earthquakes that occurred during the July 2019 sequence vs. time is pretty astonishing, though magnitudes did not surpass M2.1.

The largest earthquakes to strike Mt. Hood during the month of Jan. 2020 were two M1.2 earthquakes. One occurred at 3.1km in depth on Jan. 23, 2020 at 23:08UTC directly under the summit of Mt. Hood. The other M1.2 struck at 3.0km in depth on Jan. 27, 2020 at 06:53UTC under the SE slopes of the volcano. Both events are shown directly below, with the M1.2 on January 23 shown first:

I often call Mt. Shasta "California's Mt. Hood", and sometimes rightfully so since it basically carries the same monthly seismicity. Mt. Hood in Oregon saw one of its most energetic swarms in July 2019. Well, Mt. Shasta actually saw its most powerful swarm in September 2019, please CLICK HERE to see information and plots of that event.

The earthquake totals and the maximum magnitudes of the Sept. 2019 swarm at Mt. Shasta really was insignificant compared to past swarms at other volcanoes in the USA. However, in regards to Mt. Shasta itself, the Sept. 2019 swarm likely was the most powerful and energetic swarm the volcano had seen in many decades.

However, January 2020 was a very calm month with only two earthquakes occurring around its perimeter. The largest earthquake reported around Mt. Shasta was a M1.8 at 4.1km in depth on Jan. 23, 2020 at 19:15UTC. It struck ~10km or so SSE of the summit and there was surprisingly one felt report. Below are the plots of this event:

Lassen Volcanic Center, which is the southern most volcanic system in the Cascade Range, remains within normal background levels of seismicity. There were a total of 23 earthquakes for this location during January 2020.

The largest was a M1.4 at 3.1km in depth on Jan. 31, 2020 at 00:41UTC. It struck directly beneath Lassen Peak. The plots below show this event:

The location of Pahala, Hawaii, and the depths beneath it, are not a volcano in and of itself. However, the majority of the seismicity that occurs in this region, between ~20km and ~60km in depth, is related to the mantle plume conduits that feed the volcanoes on the Big Island. Spasmodic tremor, CLICK HERE if you don't know what it is, has been prevalent in the same depth and location as the earthquake swarms under Pahala ever since the eruptions in Hawaii stopped in September 2018.

Increases in seismicity within the mantle plume under Pahala are sometimes associated with increases in shallow crustal earthquakes around Kilauea and Mauna Loa. For this reason, I thought it best to monitor the situation with monthly updates. There are some earthquakes within the area box that may not have occurred within the mantle plume conduit(s). However, around 90-95% in this location have, unless otherwise stated.

I know this is not the official month my monthly updates will start including Pahala, HI, but I thought I would quickly post something here about this location.

During December 2019 and January 2020, there were 681 earthquakes reported by HVO during that two month time frame. The largest was a M3.5 at 35.1km in depth on Jan. 7, 2020 at 21:19UTC.

There were also eight spasmodic tremor events during those two months. If you wish to see those now, please CLICK HERE to visit my blog post about them!


Well, that is it for now! Any mistakes or suggestions? Comment here on this post, shoot me an email at washingtonmagma@yahoo.com, or message me on Facebook (Ben Ferraiuolo)!

This is the monthly volcano report for December 2019. If you already know what this usual intro says, please click the title of this post or “read more” to continue. The reported earthquake counts are taken directly from the U.S.G.S. and are only earthquakes reported, not earthquakes recorded. Regarding earthquake counts, it is likely that the reported earthquake total for a given location and time period, mostly during earthquake swarms, is lower than the actual count of earthquakes, in certain cases sometimes drastically lower. Remember, most earthquake swarms at volcanoes do not lead to eruptions. However, almost every eruption is preceded by some type of earthquake swarming and surface deformation. Therefore, swarms and deformation should always be monitored closely regardless of where you think the activity is headed.
 
The volcanoes I will be doing monthly updates on are Yellowstone Caldera in Wyoming, Long Valley Caldera in California, Newberry Caldera and Mt. Hood in Oregon, Mt. Rainier and Mt. St. Helens in Washington state, and Mt. Shasta and Lassen Peak in California. In this update, we will look at reported seismicity counts. If you wish to see recent deformation for Yellowstone or Long Valley, please head to the “Deformation Updates” page which is updated every 2 months or so.
 
The time period of the reported seismicity counts for this update, derived from the USGS earthquake catalog, is from 00:00UTC Dec. 1, 2019 through 23:59UTC December 31, 2019 and magnitudes are always going to be -1.0 and above so you will see every single earthquake that was reported for this time period. The smallest earthquake ever recorded was a M-1.0 and the largest earthquake ever recorded was a M9.5. Also, the coordinate box I use for each volcano is exactly the same every month, so you always see the activity that occurred in the same area every month. Regarding the 3-plot seismic images I generate for the largest events, I will always try my best to use the closest seismic station to any given event. I will also add the link to the USGS EQ map showing the locations of reported seismicity for the location and time period in question.

December 2019 was another mediocre month for seismicity at Yellowstone. Except for a few magnitude 3s and some very short and energetic swarming, this month was boring. Regardless, we did see some interesting earthquakes including a few M3s which were the largest to strike this region in a few years. Only 93 earthquakes were located during December. A few other small events may not have been reported, but seismicity was generally low for this month.

The largest earthquake this month was a M3.5 at 17km in depth on Dec. 15, 2019 at 12:32UTC. It struck just barely outside of the western border of Yellowstone National Park, just 25km WSW of Old Faithful Geyser. It was the largest to strike Yellowstone since a M3.6 struck Maple Creek on July 18, 2017. December's M3.5 was reportedly felt by 5 people which is quite the achievement since there are hardly any people, if any at all, in this area during this time of year. The plots directly below are of this event:

Surprisingly, there was also a M3.4 on this same day. It was the largest earthquake for December 2019 to strike within the caldera itself and is likely the largest earthquake to strike the caldera itself in many years. It struck at 4.0km in depth just 10 hours prior to the event shown above. The epicenter was very close to Mary Lake. Directly below are plots of this event. Notice the strange spectrogram signature at the start of the event:

Steamboat Geyser, the largest active geyser in the world at Norris, remained active through the month of December 2019. It erupted a total of 3 times during December. The last eruption of this month, and for all of 2019, was the 48th eruption which occurred at 04:34UTC on December 27, 2019 (9:34pm Mountain Time, December 26, 2019). The grand total of eruptions during the 2018-2019 is 80 eruptions! That is alot! Plots shown directly below are of the last eruption of 2019:

During the month of December 2019, there were 373 earthquakes for the Long Valley Caldera region. That is the lowest count since June 2019! Seismicity continues to decline every month now since the intense swarming seen in September (CLICK HERE to see information about that). However, the decline can only go on for so long and another period of unrest similar to that seen in September is almost certain.

The largest earthquake to strike Long Valley in December 2019 was a M3.6 at 9.9km in depth on December 26, 2019 at 19:48UTC.  It struck along the southern rim of the caldera just 13km W of Toms Place, CA. Over 161 people felt this event which was originally labeled a M4.0. Plots directly below are of this event:

Although October and November saw no seismicity, December 2019 saw 2 reported events. Both contained high frequencies and low frequency activity still has not reemerged since it dwindled away in the summer of 2019.

The largest event for Newberry Caldera for December 2019 was a M0.5 "Other Event" supposedly at -1.7km in depth. It struck under the NE base of Newberry Caldera under N Paulina Lake Rd. on December 28, 2019. I am unsure why it was labeled as "Other Event". You can clearly see in the plots below that this appears to be a normal high frequency earthquake (however there are some slightly stronger lower frequencies):

The only other earthquake to strike Newberry in December was a M0.3 at 4.0km in depth on December 16, 2019 at 20:30UTC. It struck around 5 miles NW of Newberry directly under the Lava Cast Forest. Directly below are plots of this micro-quake:

Although Mt. Rainier is still within normal background levels, this volcano saw its highest monthly count in over 6 months. There were 35 earthquakes located for December 2019. Only a few were scattered around the perimeter and most events this month occurred under the edifice of the volcano. This isn't a major increase in anyone's standard, but it is interesting nonetheless!

The largest earthquake to strike Mt. Rainier in December 2019 was a M1.4 at 1.5km in depth on December 19, 2019 at 21:02UTC. It struck directly beneath the volcano. Below are plots of this event:

December 2019 was a very calm month for one of the most active volcanoes in the United States. Mt. St. Helens saw only 11 earthquakes during this month. This was likely one of the calmest months in 2019 for this volcano.

The largest earthquake to strike Mt. St. Helens was a M0.8 at 10km in depth on December 10, 2019 at 06:25UTC. It struck about 5 miles SW of the summit. Plots below are of this event:

During December 2019, Mt. Hood experienced only 3 earthquakes. Seismicity has returned to background levels since the large spike in seismicity in July 2019 (CLICK HERE for information on that crazy swarm). This month saw two earthquakes strike under the edifice and one small micro-quake to the SW near the epicenter of the July swarming.

The largest event of December 2019 for Mt. Hood was a M2.4 at 1.9km in depth on December 9, 2019 at 01:00UTC. It struck directly under Mt. Hood. This earthquake was the largest one to strike Mt. Hood since the M2.8 at 6.8km in depth on Oct. 10, 2017. Not even the largest swarm in this area, which occurred July 2019, had an earthquake this large. Regardless, Mt. Hood remains in background levels. Below are plots of the largest event of December 2019:

Seismicity has continued to decline dramatically since one of the largest swarms in decades struck Mt. Shasta in September 2019 (CLICK HERE for more information about that). Only two earthquakes were located for Mt. Shasta during the month of December and they both were about 7 miles north of the summit. The largest was a M0.8 at 1.3km in depth on December 2, 2019 at 03:38UTC. Plots below are of this event:

Lassen Volcanic Center was very calm this month as well with only 11 earthquakes being located for December 2019. The largest was a M1.7 at 5.9km in depth on December 5, 2019 at 16:10UTC. It struck about 10 miles east of Lassen Peak. Plots below are of this event:

This is the monthly volcano report for November 2019. If you already know what this usual intro says, please click the title of this post or “read more” to continue. The reported earthquake counts are taken directly from the U.S.G.S. and are only earthquakes reported, not earthquakes recorded. Regarding earthquake counts, it is likely that the reported earthquake total for a given location and time period, mostly during earthquake swarms, is lower than the actual count of earthquakes, in certain cases sometimes drastically lower. Remember, most earthquake swarms at volcanoes do not lead to eruptions. However, almost every eruption is preceded by some type of earthquake swarming and surface deformation. Therefore, swarms and deformation should always be monitored closely regardless of where you think the activity is headed.
 
The volcanoes I will be doing monthly updates on are Yellowstone Caldera in Wyoming, Long Valley Caldera in California, Newberry Caldera and Mt. Hood in Oregon, Mt. Rainier and Mt. St. Helens in Washington state, and Mt. Shasta and Lassen Peak in California. In this update, we will look at reported seismicity counts. If you wish to see recent deformation for Yellowstone or Long Valley, please head to the “Deformation Updates” page which is updated every 2 months or so.
 
The time period of the reported seismicity counts for this update, derived from the USGS earthquake catalog, is from 00:00UTC November 1, 2019 through 23:59UTC November 30, 2019 and magnitudes are always going to be -1.0 and above so you will see every single earthquake that was reported for this time period. The smallest earthquake ever recorded was a M-1.0 and the largest earthquake ever recorded was a M9.5. Also, the coordinate box I use for each volcano is exactly the same every month, so you always see the activity that occurred in the same area every month. Regarding the 3-plot seismic images I generate for the largest events, I will always try my best to use the closest seismic station to any given event. I will also add the link to the USGS EQ map showing the locations of reported seismicity for the location and time period in question.

There are no volcanoes of interest this month, other than a small LF event at Lassen Peak at a very minor swarm at Mt. Rainier. Please click the title of this post or "read more" to continue...

Seismicity has been mediocre lately at Yellowstone. Aside from the small swarm here and there, deformation and seismicity has been underwhelming. Regardless, 121 earthquakes were reliably located during November 2019 with likely many more earthquakes not reliably located (meaning they were extremely small).

A small swarm broke out near Mary Lake on Nov. 25 and a rapid-fire swarm struck the west-central shores of West Thumb Lake on Nov. 30. CLICK HERE to view some plots of those swarms.

The largest event to strike Yellowstone National Park was a M3.0 at 5.0km in depth on Nov. 10, 2019 at 01:28UTC. It struck 29km WNW of West Yellowstone, MT and received 2 "did you feel it" reports to USGS. Plots below are of this event:

Steamboat Geyser, the largest active geyser in the world located at Norris in Yellowstone, erupted 3 times in November 2019. Although 2018-2019 has been the most active time period on record for this geyser, November has been showing some declining activity. Regardless, it is likely Steamboat Geyser will continue its current activity for the foreseeable future. Not counting December eruptions, Steamboat Geyser has erupted 45 times in 2019 (77 times since it reactivated in early-2018). Below are the plots of the most recent eruption which occurred on Nov. 27, 2019:

November 2019 has been a slightly quieter month for Long Valley Caldera in California. Most of the seismicity this month was concentrated within the southern caldera boundaries with seismicity spreading to the south-southeast, as is the usual trend of seismicity for this caldera.

There were a total of 488 earthquakes reliably located for Long Valley Caldera which is the lowest since July 2019. Seismicity seems to keep declining ever since the spike in seismicity in September 2019. CLICK HERE for details of that seismicity increase.

The largest earthquake reported for November 2019 was a M2.9 at 3.1km in depth on Nov. 12, 2019 at 14:34UTC. It struck inside the caldera under Mammoth Lakes Airport just a few km the ESE of the Sept. seismicity. Seismicity seems to be shifting a bit from the September area now to the east a bit. I will continue to keep an eye on the movement. Plots below are of the largest event reported:

For the second month in a row, Newberry Caldera in Oregon has seen no reported seismcity. I have attempted to find seismicity of my own, but to no avail. Newberry is truly quiet.

Mt. Rainier still remains at background levels regarding seismicity and deformation. Regardless, 29 earthquakes were reliably located for Nov. 2019 which is the highest since at least June 2019 where only 20 earthquakes were reported.

A small swarm was detected under the summit on Nov. 29, 2019 in which a M2.1 at -0.1km was detected at 07:44UTC which was the largest of the month. Actually, that is the largest earthquake to strike under the summity of Mt. Rainier since the M2.3 on Feb. 24, 2016. Below are plots of the M2.1 on Nov. 29, 2019:

First off, Mt. St. Helens was steaming when I visited it in August and September of 2019. To see the footage of the minor steaming of the resurgent dome on September 12, 2019, please CLICK HERE.

Mt. St. Helens in Washington State experienced 20 reliably located earthquake events. About half occurred under the summit and the other half were scattered around the perimeter. The largest event reported for November 2019 was a M1.7 at 5.7km in depth on Nov. 4, 2019 at 07:17UTC. It struck approximately 10km SW of the summit receiving 1 felt report to USGS. Plots below are of this event:

Seismicity has continued to decline dramatically since the intense July 2019 earthquake swarm at Mt. Hood which you can read about if you CLICK HERE. That swarm was one of the largest at Mt. Hood in quite a while.

There was only 1 reported earthquake for Mt. Hood for November 2019. It was a M0.8 at 2.0km in depth on Nov. 17, 2019 at 15:33UTC under the summit. Plots below are of this event:

Although Mt. Shasta saw its most powerful swarm in decades in Sept. 2019 which you can find if you CLICK HERE, which was small compared to other volcanoes but large for Mt. Shasta, only 3 earthquakes were reported for November 2019. The largest of which was a M1.1 far to the south. However, the largest to strike Mt. Shasta itself was a M1.0 at -1.7km in depth on Nov. 18, 2019 at 13:13UTC. Plots below are of this event:

Lassen Volcanic Center experienced 11 reported earthquakes during November 2019. The largest was a M0.5 low frequency earthquake at 14.2km in depth on Nov. 30, 2019 at 14:02UTC and struck just to the west of Lassen Peak as did the low frequency event in June 2019 which you can read about in the June 2019 update if you CLICK HERE. The largest event of November 2019, which was a low frequency earthquake, is shown in the plots below:

This is the monthly volcano report for October 2019. If you already know what this usual intro says, please click the title of this post or “read more” to continue. The reported earthquake counts are taken directly from the U.S.G.S. and are only earthquakes reported, not earthquakes recorded. Regarding earthquake counts, it is likely that the reported earthquake total for a given location and time period, mostly during earthquake swarms, is lower than the actual count of earthquakes, in certain cases sometimes drastically lower. Remember, most earthquake swarms at volcanoes do not lead to eruptions. However, almost every eruption is preceded by some type of earthquake swarming and surface deformation. Therefore, swarms and deformation should always be monitored closely regardless of where you think the activity is headed.
 
The volcanoes I will be doing monthly updates on are Yellowstone Caldera in Wyoming, Long Valley Caldera in California, Newberry Caldera and Mt. Hood in Oregon, Mt. Rainier and Mt. St. Helens in Washington state, and Mt. Shasta and Lassen Peak in California. In this update, we will look at reported seismicity counts. If you wish to see recent deformation for Yellowstone or Long Valley, please head to the “Deformation Updates” page which is updated every 2 months or so.
 
The time period of the reported seismicity counts for this update, derived from the USGS earthquake catalog, is from 00:00UTC October 1, 2019 through 23:59UTC October 31, 2019 and magnitudes are always going to be -1.0 and above so you will see every single earthquake that was reported for this time period. The smallest earthquake ever recorded was a M-1.0 and the largest earthquake ever recorded was a M9.5. Also, the coordinate box I use for each volcano is exactly the same every month, so you always see the activity that occurred in the same area every month. Regarding the 3-plot seismic images I generate for the largest events, I will always try my best to use the closest seismic station to any given event. I will also add the link to the USGS EQ map showing the locations of reported seismicity for the location and time period in question.

Volcanoes of interest this month are Yellowstone and Mt. Rainier. However, this is one of the calmest months I have seen for a while for volcanoes here in the United States, especially for the Cascade Range volcanoes.

During the month of October 2019, Yellowstone Caldera experienced 195 reported earthquake events. This number is higher than the previous month's total of 72 reported earthquakes. October's total is likely smaller than the actual count of earthquakes especially since the October 26-28 earthquake swarm NW of the Norris Geyser Basin near Holmes Hill.

As seen below, there was an energetic swarm on those dates. It was a rapid-fire swarm and could be indicative of hydrothermal fluid migration which does happen from time to time since Yellowstone has an extremely immense hydrothermal-magmatic system.

86 events were reported for this swarm so almost half of this month's total was due to the October 26-28 swarm. Other than this swarm, this was a typical month for Yellowstone Caldera.

The largest earthquake to strike Yellowstone National Park within the month of October 2019 was a M2.9 event at 8.3km in depth on Oct. 16, 2019 at 17:08UTC. It struck just a few miles to the NNE of Canyon Junction, to the NE of Norris. The plots shown below are of this event:

Steamboat Geyser, the largest active geyser in the world located within the Norris Geyser Basin, erupted a total of 5 times during October 2019. Steamboat Geyser remains active and appears to still be erupting on a near-weekly schedule. The video below is the stream of the last eruption of 2019 which was the 42nd eruption of 2019 (the 74th eruption since the early-2018 reactivation).

Long Valley Caldera saw a total of 604 reported earthquake events for October 2019. This is much lower than the high total of 1,115 earthquakes in September. September saw a fairly intense period of seismicity that occurred in multiple episodes during the whole month. This can be seen in my blog post about that seismicity if you click HERE.

October's seismicity was concentrated around the epicenter of the September swarming, south of the caldera rim, and to the SE near Bishop, CA.

The largest event of the month was a M3.3 at 8.2km in depth on Oct. 26, 2019 at 19:39UTC. It struck SE of the caldera near Bishop, CA and 42 people submitted a report to USGS that they felt this event. Plots below are of this event:

The largest event to strike within the caldera itself was a M2.6 at 5.3km in depth on Oct. 9, 2019 at 07:57UTC. It struck near the epicenter of the September swarming and USGS received 2 felt reports for this event. Plots below are of this earthquake:

Newberry Caldera in Oregon saw no reported events of any magnitude. Check back next month.

Mt. Rainier experienced 24 reported earthquake events for the month of October 2019. This is just barely lower than last month's total of 27 earthquakes. However, 11 of the reported events for October occurred during a small swarm on October 29 which struck directly under the volcano edifice.

The largest event for October was a M2.1 at 0.9km in depth on October 29, 2019 at 08:57UTC. It struck directly under the volcano as part of the minor October 29 swarm. Plots below are of this event:

Just FYI, I visited Mt. St. Helens 3 times recently and the past 2 times I visited the dome was steaming. It was a pretty cool sight, so please CLICK HERE to see a video of Mt. St. Helens slightly steaming on Sept. 12, 2019.

Mt. St. Helens saw a total of 18 reported earthquake events for October 2019. This is lower than last month's total of 25 earthquakes. The largest event for October was a M0.7 at 0.3km in depth on October 25, 2019 at 11:15UTC. It struck directly beneath the volcano edifice. Plots below are of this event:

Mt. Hood in Oregon surprisingly saw 0 reported earthquake events for October 2019. Mt. Hood has been extremely quiet following the intense July 2019 earthquake swarm. CLICK HERE for information on that swarm.

Mt. Shasta in California surprisingly saw 0 reported earthquake events. Shasta has been suspiciously quiet after the September 2019 earthquake swarm. It was likely the largest swarm at Mt. Shasta in decades. CLICK HERE for information about that swarm.

Lassen Volcanic Center experienced 19 reported earthquake events for the month of October 2019. This is higher than last month's total of 10 reported earthquakes. The largest event was a M1.4 at 3.2km in depth on Oct. 23, 2019 at 04:47UTC. It struck under Lassen and the plots below are of this event:

This is the monthly volcano report for September 2019. If you already know what this usual intro says, please click the title of this post or “read more” to continue. The reported earthquake counts are taken directly from the U.S.G.S. and are only earthquakes reported, not earthquakes recorded. Regarding earthquake counts, it is likely that the reported earthquake total for a given location and time period, mostly during earthquake swarms, is lower than the actual count of earthquakes, in certain cases sometimes drastically lower. Remember, most earthquake swarms at volcanoes do not lead to eruptions. However, almost every eruption is preceded by some type of earthquake swarming and surface deformation. Therefore, swarms and deformation should always be monitored closely regardless of where you think the activity is headed.
 
The volcanoes I will be doing monthly updates on are Yellowstone Caldera in Wyoming, Long Valley Caldera in California, Newberry Caldera and Mt. Hood in Oregon, Mt. Rainier and Mt. St. Helens in Washington state, and Mt. Shasta and Lassen Peak in California. In this update, we will look at reported seismicity counts. If you wish to see recent deformation for Yellowstone or Long Valley, please head to the “Deformation Updates” page which is updated every 2 months or so.
 
The time period of the reported seismicity counts for this update, derived from the USGS earthquake catalog, is from 00:00UTC September 1, 2019 through 23:59UTC September 30, 2019 and magnitudes are always going to be -1.0 and above so you will see every single earthquake that was reported for this time period. The smallest earthquake ever recorded was a M-1.0 and the largest earthquake ever recorded was a M9.5. Also, the coordinate box I use for each volcano is exactly the same every month, so you always see the activity that occurred in the same area every month. Regarding the 3-plot seismic images I generate for the largest events, I will always try my best to use the closest seismic station to any given event. I will also add the link to the USGS EQ map showing the locations of reported seismicity for the location and time period in question.
 
Volcanoes of interest for this month are Long Valley Caldera and Mt. Shasta. Please click the title of this post or “read more” to continue…

During September 2019, there were 72 reported earthquakes for Yellowstone National Park. This count is lower than the past 3 months and September was a boring month for Yellowstone earthquake enthusiasts. No moderate to major swarming took place during this month.

Steamboat Geyser, which resides in the Norris Geyser basin, continues to shatter the 2018 record since it broke the record on August 27, 2019. Steamboat erupted 4 times in September 2019, basically once per week. As of the time of this writing, October 9, 2019, Steamboat has erupted 39 times in 2019, 71 times since it reactivated in early-2018.

The largest earthquake within Yellowstone National Park for September was a M2.4 at 15.7km in depth. It struck on Sept. 8, 2019 at 19:59UTC along the western border of the national park, just 17km south of West Yellowstone, MT. Plots are shown below of this event.

September 2019 was a very active month for Long Valley Caldera. There were a shocking 1,115 earthquakes reported for the Long Valley Caldera area during this month. A large majority of the seismicity occurred as part of swarming near Mammoth Lakes, CA which resides within the caldera itself. Please click the button above if you wish to see some info and data pertaining to the energetic swarming that took place.

The swarming started on Sept. 13 and struck on and above the roof of the magma chamber beneath the caldera. The swarm also was non-linear in formation and looks more like fluid flow rather than tectonic activity.

Also, for a few months prior to September, seismicity was slowly growing for the caldera. For example, June saw around 340 quakes reported, July saw around 405, August saw around 643, and September of course saw around 1,115 earthquakes.

The largest events of this month were actually two M3.0 earthquakes. One occurred at 5.3km in depth on September 25 as part of the ongoing swarming near Mammoth Lakes, CA. The other one struck at 5.1km in depth on September 27 along the southern rim of the caldera. Both quakes were reportedly felt by multiple people. The plots below are of the M3.0 on September 25, 2019 which struck near Mammoth Lakes, CA.

Newberry Caldera saw a total of 3 reported earthquake events for September 2019. Newberry remains within background levels and is usually very quiet. Low frequency earthquakes used to dominate seismicity for a few years at Newberry. However, as of the past 5 months or so, low frequency seismicity has not been reported or noticed by amateur seismologists.

The largest earthquake reported was a M0.3 at 2.9km in depth on Sept. 16, 2019 at 12:00UTC just under the eastern caldera lake called East Lake. Plots below are of this event.

During September 2019, Mt. Rainier saw 27 reported earthquakes. This is higher than last months total of 21 earthquakes. Included within the 27 reported events there was a strange M-0.0 "Other Event", which will be mentioned in just a second.

Most of the seismicity this month occurred within the volcano itself. The largest event was a M1.6 at -2.7km in depth. Very shallow, but still within the edifice of the volcano. It struck on Sept. 7, 2019 at 10:49UTC. Plots below are of this earthquake.

Now, on September 26, 2019 at 19:10UTC there was a very strange M-0.0 "Other Event" at -2.3km in depth under the SE slopes of the volcano. It does not appear to be a glacier earthquake or avalanche. However, it is a very strange event nonetheless. Was this truly seismic? Or was this surface activity? If this were a surface event, I doubt USGS would have labeled it as a M-0.0 "Other Event".

The seismogram plots below are from 3 select stations around Mt. Rainier. Station RCS was the closest station to this event. Station OBSR is further to the northwest and station RUSH is even further west. So it is interesting this event traveled so far in the way that it did if this was a surface event.

First off, I visited Mt. St. Helens on August 13 and September 12 of 2019. Both times I noticed the dome was slightly steaming, even though it was not steaming earlier in August when I first visited it. CLICK HERE to see the footage of St. Helens steaming on August 13. However, CLICK HERE to see it steam even more on September 12.

Mt. St. Helens experienced 25 reported earthquakes for Sept. 2019. Most occurred directly under the summit. The largest event was actually an explosion to the NW but that was likely a logging blast of some sort. For the largest earthquake this month, it was reportedly a M1.0 at -1.1km in depth, very shallow right under the summit. It struck on Sept. 17, 2019 at 06:02UTC. Plots below are of this event.

Mt. Hood in Northern Oregon experienced 13 reported earthquake events. That is 3 higher than last month's total. Remember, July saw a total of 155 earthquakes reported within only a few days. It was a very energetic and rapid-fire swarm so please CLICK HERE to visit my blog post about that crazy earthquake swarm.

Most of the earthquakes this month occurred under the southern base of the volcano with a few striking under the volcano itself. The largest event of Sept. 2019 was a M1.6 at 6.8km in depth. It struck on Sept. 5, 2019 at 06:35UTC under the southern base of the volcano. Plots below are of this event.

September 2019 was an extremely intriguing month for Mt. Shasta. Although Shasta typically only sees a few earthquakes reported per month, there were 47 events reported for Sept. 2019. Almost all of these events occurred within a very short time frame of 1 day and occurred in a concentrated patch under the SE base of the volcano.

Although Mt. Shasta has seen swarms before, and this swarm was small compared to swarms at other volcanoes, this was likely the largest earthquake swarm to strike Mt. Shasta in decades. If you wish to see my blog post about this swarm, and the swarm many years prior to this, please CLICK HERE.

The largest reported earthquake for Sept. 2019 was a M2.7 at 5.6km in depth on Sept. 2, 2019 at 17:34UTC. It occurred under the SE section of Mt. Shasta and struck as part of the Sept. 2-3, 2019 earthquake swarm. 19 people reported feeling the M2.7 which is impressive for an earthquake of that size and depth. Plots below are of this event.

Lassen Volcanic Center, a.k.a. LVC, experienced 10 reported earthquake events for Sept. 2019. That is pretty low compared to the last two months of seismicity. The largest event this month was a M1.4 at 5.7km in depth on Sept. 4, 2019 at 10:38UTC. It struck just SSW of Lassen Peak. Plots below are of this event.

This is the monthly volcano report for August 2019. If you already know what this usual intro says, please click the title of this post or “read more” to continue. The reported earthquake counts are taken directly from the U.S.G.S. and are only earthquakes reported, not earthquakes recorded. Regarding earthquake counts, it is likely that the reported earthquake total for a given location and time period, mostly during earthquake swarms, is lower than the actual count of earthquakes, in certain cases sometimes drastically lower. Remember, most earthquake swarms at volcanoes do not lead to eruptions. However, almost every eruption is preceded by some type of earthquake swarming and surface deformation. Therefore, swarms and deformation should always be monitored closely regardless of where you think the activity is headed.
 
The volcanoes I will be doing monthly updates on are Yellowstone Caldera in Wyoming, Long Valley Caldera in California, Newberry Caldera and Mt. Hood in Oregon, Mt. Rainier and Mt. St. Helens in Washington state, and Mt. Shasta and Lassen Peak in California. In this update, we will look at reported seismicity counts. If you wish to see recent deformation for Yellowstone or Long Valley, please head to the “Deformation Updates” page which is updated every 1-2 months.
 
The time period of the reported seismicity counts for this update, derived from the USGS earthquake catalog, is from 00:00UTC August 1, 2019 through 23:59UTC August 31, 2019 and magnitudes are always going to be -1.0 and above so you will see every single earthquake that was reported for this time period. The smallest earthquake ever recorded was a M-1.0 and the largest earthquake ever recorded was a M9.5. Also, the coordinate box I use for each volcano is exactly the same every month, so you always see the activity that occurred in the same area every month. Regarding the 3-plot seismic images I generate for the largest events, I will always try my best to use the closest seismic station to any given event. I will also add the link to the USGS EQ map showing the locations of reported seismicity for the location and time period in question.
 
Please click the title of this post or “read more” to continue…

CLICK HERE to visit the USGS EQ map for this location and time period.

During the month of August 2019 we see a total of 129 earthquakes which is 10 less reported events than the previous month. Seismicity was spread around the caldera as usual, however there was a rapid-fire swarm just south of West Thumb Lake. The two rapid-fire swarms, which occurred on August 29 and August 31, appears to have been caused by fluid migration along the northern section of the East Mount Sheridan fault system. Not every earthquake within these swarms were reported, so that means the total earthquake count for this month is definitely higher.

CLICK HERE to visit my analysis page, which includes seismic plots and audio, on the Aug. 29, 2019 swarm which was the largest rapid-fire swarm at Yellowstone since December 31, 2018.

CLICK HERE to visit my analysis page, which includes seismic plots and audio, on the Aug. 31, 2019 swarm which was a continuation of the Aug. 29 swarm.

The largest earthquake at Yellowstone for the month of August 2019 was a M3.5 at 7.4km in depth on August 15, 2019 at 19:46UTC. It struck far to the south along the southern border of Yellowstone National Park. It also is the largest earthquake to strike Yellowstone since the M3.6 near Maple Creek on July 18, 2017. Plots below of this event:

Also, Steamboat Geyser erupted 3 times within the month of August 2019. Although the eruption count was lower this month, Steamboat officially beat the all-time record and on August 27, 2019 erupted for the 33rd time of 2019. The previous top records were 32 eruptions in 2018 and 29 eruptions in 1964. 2019 is by far the most active year on record for Steamboat Geyser. CLICK HERE to keep tabs on my Steamboat eruption page for 2019.

CLICK HERE to visit the USGS EQ map for this location and time period.

During the month of August 2019, Long Valley Caldera witnessed 643 reported earthquakes which is much higher than the previous 2 months. Is seismicity increasing for Long Valley? It is too early to tell but we should keep an eye on the situation.

As usual, most seismicity was located in the south-central part of the caldera with additional seismicity spreading to the south and far to the southeast. A few minor quakes also struck to the NNE.

The largest reported earthquake for this time period was a M2.9 at 7.4km in depth on August 23, 2019 at 19:04UTC. It occurred within the caldera rim along the southern section. More events occurred on this day as part of a minor swarm. The largest event can be seen via the plots below. The first event you see is the M2.9 and the second event you see is an aftershock.

CLICK HERE to visit the USGS EQ map for this location and time period.

Although seismicity over the past couple years has been largely dominated by low frequency earthquakes, there hasn't been much of a resurgence of LF events. Only 1 earthquake was reported for Newberry during the month of August 2019. It was a M0.3 at 3.5km in depth on August 6, 2019 at 23:02UTC. Plots of this event are shown below:

CLICK HERE to visit the USGS EQ map for this location and time period.

USGS/PNSN located 21 earthquake events for Mt. Rainier during the month of August 2019 which is lower than last month's total of 30 events. August 2019 was also the month where I visit Mt. Rainier in person 3 times! It was amazing and a great place to go for volcano-lovers.

During August 2019, about half of the seismicity occurred along the West Rainier Seismic Zone (WRSZ) and the other half occurred under the volcano itself. The largest event for this entire area for August 2019 was a M1.4 at 11.2km in depth on August 7, 2019 at 20:28UTC. It struck along the WRSZ. The largest event to strike under the volcano itself was a M1.1 at -2.3km in depth on August 8, 2019 at 20:34UTC under the ENE slope. Both events can be seen via both images below:

CLICK HERE to visit the USGS EQ map for this location and time period.

During the month of August 2019, there were a total of 17 located earthquakes around the Mt. St. Helens area. A little more than half of these events occurred to the north and to the northeast. Around 6 events occurred under the summit itself.

In August 2019 Mt. St. Helens was also caught steaming! It was during my trip to Mt. St. Helens with my family on August 13, 2019 and I caught some good footage of the dome slightly steaming. It was not doing that on August 6 when I first went there. CLICK HERE to check out that video.

The largest event of August 2019 was a M1.2 at 15.5km in depth to the NW, just WNW of Johnston Ridge Observatory. It struck on August 30, 2019 at 04:20UTC. Plots of this event are shown below:

CLICK HERE to visit the USGS EQ map for this location and time period.

During the month of August 2019, Mt. Hood saw 10 reported earthquake events. Most of the seismicity this month was concentrated to the SW of the summit along the location where the July 2019 swarm took place (CLICK HERE).

The largest reported earthquake for August 2019 was a M1.3 at 0.2km in depth on August 24, 2019 at 12:47UTC. It struck just under the northern base of the volcano. Plots are shown below of this event:

CLICK HERE to visit the USGS EQ map for this location and time period.

I know it didn't happen in August, but Mt. Shasta just experienced its largest earthquake swarm in over 2 decades. The last time a swarm likely occurred this strong was in 1993. CLICK HERE to visit my page about the Sept. 2-3, 2019 Mt. Shasta rapid-fire swarm.

For August 2019, Mt. Shasta saw only 4 reported earthquakes which is the same as July's total and higher than June's total. They were all far to the SSE beyond the base, near McCloud, CA. The largest reported event for August 2019 was a M1.8 at 3.8km in depth on August 13, 2019 at 01:37UTC. Plots of this event are shown below:

CLICK HERE to visit the USGS EQ map for this location and time period.

During the month of August 2019, Lassen Volcanic Center experienced 19 earthquake events which is 1 higher than last month's total. A few quakes struck to the north, a few struck under Lassen Peak, and the rest struck to the SE of Lassen Peak.

The largest event of August 2019 was a M2.1 at 7.4km in depth on August 30, 2019 at 23:33UTC. It struck to the SE of Lassen and struck along with a few other earthquakes during this day (as can be seen via the plots below):

Welcome to my new and simplified monthly volcano updates! This is the monthly volcano report for July 2019. The reported earthquake counts are taken directly from the U.S.G.S. and are only earthquakes reported, not earthquakes recorded. Regarding earthquake counts, it is likely that the reported earthquake total for a given location and time period, mostly during earthquake swarms, is lower than the actual count of earthquakes, in certain cases sometimes drastically lower. Remember, most earthquake swarms at volcanoes do not lead to eruptions. However, almost every eruption is preceded by some type of earthquake swarming and surface deformation. Therefore, swarms and deformation should always be monitored closely regardless of where you think the activity is headed.
 
The volcanoes I will be doing monthly updates on are Yellowstone Caldera in Wyoming, Long Valley Caldera in California, Newberry Caldera and Mt. Hood in Oregon, Mt. Rainier and Mt. St. Helens in Washington state, and Mt. Shasta and Lassen Peak in California. In this update, we will look at reported seismicity counts. If you wish to see recent deformation for Yellowstone or Long Valley, please head to the “Deformation Updates” page which is updated every 1-2 months.
 
The time period of the reported seismicity counts for this update, derived from the USGS earthquake catalog, is from 00:00UTC July 1, 2019 through 23:59UTC July 31, 2019 and magnitudes are always going to be -1.0 and above so you will see every single earthquake that was reported for this time period. The smallest earthquake ever recorded was a M-1.0 and the largest earthquake ever recorded was a M9.5. Also, the coordinate box I use for each volcano is exactly the same every month so you always see the activity that occurred in the same area every month. Regarding the 3-plot seismic images I generate for the largest events, I will always try my best to use the closest seismic station to any given event. I will also add the link to the USGS EQ map showing the locations of reported seismicity for the location and time period in question.
 
The volcanoes of interest for this month are Mt. Hood and Mt. Shasta. Please click the title of this post or “read more” to continue…

CLICK HERE to visit the USGS EQ map for this time period and location.

During July 2019, Yellowstone National Park experienced 139 earthquakes of all magnitudes, which is higher than June's total of 74. Most of the seismicity was centered near Mary Lake and near the Lower Geyser Basin. Just a few kilometers to the ENE of the Lower Geyser Basin, about 12 kilometers NNE of Old Faithful, multiple small earthquake swarms broke out. They did not seem to occur along any known fault, leading me to suspect they were caused by fluid migration. A post showing seismic data of the July 23, 2019 Lower Geyser Basin swarm can be found if you CLICK HERE.

The largest swarm in July at Yellowstone was on July 23, 2019 in that same location. It was energetic, but not technically a "rapid-fire" swarm in my opinion. The largest earthquake to strike Yellowstone was part of this earthquake swarm. It was a M2.9 at 7.9km in depth on July 23, 2019 at 06:40UTC just to the ENE of the Lower Geyser Basin. Plots of this event are shown below:

During July 2019, Steamboat Geyser in the Norris Geyser Basin erupted a total of 5 times. CLICK HERE to check out those eruptions on my Steamboat Geyser page. As of right now, August 10, 2019 at 00:53UTC, Steamboat Geyser still has not erupted. It has been over 9 days since the last eruption and we only need 3 more eruptions to beat the all-time yearly record. It just might erupt tonight after I complete this post, so check my Steamboat page to see if it has! The plots below are of the most recent Steamboat eruption which occurred on July 30, 2019.

CLICK HERE to visit the USGS EQ map for this location and time period.

During July 2019, Long Valley Caldera experienced 405 reported earthquakes of all magnitudes, which is higher than June's 340 reported events. Most of the earthquakes are in the usual spots: Under Mammoth Mountain, along the southern caldera rim, and more spread to the south, trending SSE. The largest earthquake to strike Long Valley Caldera during July 2019 was a M3.3 at 10.6km in depth on July 7, 2019 at 18:08UTC. It struck 10km or so south of the southern caldera rim and 6 people reported feeling it. Plots of this event are shown below:

CLICK HERE to visit the USGS EQ map for this location and time period.

During July 2019, there were 3 reported earthquake vents for the Newberry Caldera area, which is higher than the total of 0 for the month of June. Although low frequency earthquakes have primarily dominated seismicity at Newberry over the past 1-2 years, no low frequency earthquakes have been seen for the past few months. The largest earthquake to strike the Newberry area in July 2019 was a M0.9 at at 6.8km in depth on July 7, 2019 at 04:54UTC. It struck to the SW of the caldera. The other earthquake, a M0.7 at 6.5km in depth, struck just a few seconds prior to the M0.9. Because of this, both of these earthquakes are shown via the plots below:

CLICK HERE to visit the USGS EQ map for the location and time period.

During July 2019, Mt. Rainier experienced 30 reported earthquakes of all magnitudes, which is higher than June's total of 20. As usual, most earthquakes occurred to the west along the West Rainier Seismic Zone (WRSZ). However, a few did occur under the summit and under the northwest base.

The largest earthquake to strike the Mt. Rainier area was a M1.4 at 11.5km in depth on July 5, 2019 at 18:31UTC along the WRSZ. The largest earthquake to strike under Mt. Rainier itself, striking directly under the summit, was a M1.1 at 1.8km in depth on July 1, 2019 at 10:53UTC. Both earthquakes are shown via the two 3-plot images below:

CLICK HERE to visit the USGS EQ map for this location and time period.

During July 2019, Mt. St. Helens experienced 47 reported earthquakes of all magnitudes, which is about half of June's total of 86. The largest earthquakes reported for Mt. St. Helens for July 2019 were two M1.3 events with both striking on July 1, 2019. One struck at 2.8km in depth at 09:13UTC and the other struck at 3.0km in depth at 09:39UTC. Both occurred directly under the summit and both can be seen via the plots below:

CLICK HERE to visit the USGS EQ map for this location and time period.

Check out this image below from the FAQs section at usgs.gov. See where it says a swarm of 60 quakes were detected in 5 days and sparked the development of an emergency response? Well, this recent swarm in July 2019 was far, far more energetic and contained many more earthquakes than the swarm of 1980. Regardless, Mt. Hood currently is showing no signs of an imminent eruption. We should be on the lookout though!

The largest earthquake to strike Mt. Hood in July 2019 were 4 M2.1 earthquakes striking between 3.6km and 4.0km in depth. All of them struck as part of the energetic July 8-10 earthquake swarm. However, to save on space, I will choose the most recent. It was a M2.1 at 4.0km in depth on July 10, 2019 at 04:23UTC and received 1 felt report. However, a M2.0 at 3.7km in depth on July 9, 2019 received 7 felt reports.

CLICK HERE to visit the USGS EQ map for this location and time period.

During July 2019, Mt. Shasta saw 4 reported earthquakes of all magnitudes, which is higher than June's total of only 1 reported earthquake. This is normal, seeing Mt. Shasta is usually extremely quiet. Regardless, this month saw something interesting. The largest reported event occurred just under the eastern base of Mt. Shasta. It was quite an interesting earthquake! I believe it could be labeled as a low frequency earthquake. However, some of the neighboring stations reported some slightly higher frequencies. So, maybe a mid-frequency earthquake? There is no such terminology yet. So I will just call it a low frequency earthquake.

It was a M1.6 at 10.9km in depth on July 25, 2019 at 00:48UTC. I have two of the closest stations possible show in the plots below. As you can see, it does appear to be a low frequency earthquake. I triple checked the data to make sure this was not an error from a global distant earthquake (teleseism) or a regional event. It definitely occurred under Mt. Shasta. So why the low frequencies? Maybe some small gas release or fluid migration? If it were fluid migration, there would be an earthquake swarm. So maybe just some minor degassing. Regardless of the cause, it sure was interesting!

CLICK HERE to visit the USGS EQ map for this location and time period.

During July 2019, Lassen Volcanic Center saw 18 reported earthquake events of all magnitudes, which is twice as many as June's total of 9 reported events. They all struck within the volcanic center itself and no earthquakes were reportedly felt. If you go to my last update, which was for June 2019, Lassen Volcanic Center experienced a couple of low frequency volcanic earthquakes. They were very fun to analyze, so check that out if you wish.

The largest earthquake to strike Lassen Volcanic Center during the month of July 2019 was a M2.0 at 1.6km in depth on July 17, 2019 at 20:47UTC. It struck directly under Lassen Peak itself. Below are plots of this event:

Please CLICK HERE if you wish to visit the USGS EQ map showing the reported events above.

In the month of June 2019, 74 earthquakes were reported for the Yellowstone National Park area. A few minor rapid-fire swarms did take place during this month, most notably along the East Mount Sheridan fault system. Please check my "Yellowstone Super-Volcano" blog page, which resides somewhere in the "Seismic Events" menu, if you wish to see plots for those swarms.

Steamboat Geyser, which resides in the Norris Geyser Basin, erupted a shocking total of 7 times during the month of June 2019. I don't know for sure, however I think that is a record for one calendar month. June 2019 was a very busy month for Steamboat Geyser. Don't forget to monitor my "Steamboat 2019" page which also resides somewhere in the "Seismic Events" menu.

The largest earthquake to occur at Yellowstone National Park and Caldera for the month of June 2019 was a M2.7 at 8.2km in depth on June 28, 2019 at 6:42UTC. It struck roughly 30-40km SSE of Yellowstone's south caldera rim. You can see its location on the map above, which would be the earthquake shown farthest to the south. Here are the seismogram, spectrogram, and spectra plots detailing this earthquake from the closest seismic station:

Please CLICK HERE to visit the USGS EQ map for this location and time period.

During the month of June 2019, USGS reported 340 earthquakes for the whole month. Note most of the seismicity is located in the south-central part of the caldera, with some quakes striking along a SSE trend south of the caldera. Other quakes also struck Mammoth Mountain to the west and farther to the SE near Bishop, CA.

This month included a very energetic swarm, much like the rapid-fire swarms which are seen at Yellowstone from time to time. I included plots to this swarm in my blog post about these events. Please go to the "Seismic Events" menu and go to the "Quake Swarms" page.

The largest earthquake to strike Long Valley Caldera during the month of June 2019 was a magnitude 2.8 at 6.0km in depth on June 28, 2019 at 9:24UTC. It struck just a few kilometers south of Long Valley's southern caldera rim. Also, 3 people reported to USGS that they felt this earthquake. Below are the seismogram, spectrogram, and spectra plots detailing the largest event of June 2019:

There were no earthquakes reported for Newberry Caldera for the month of June 2019. Regardless, CLICK HERE to visit the USGS EQ map.

Please CLICK HERE to visit the USGS EQ map for this location and time period.

During the month of June 2019, USGS reported 20 earthquakes for the Mt. Rainier National Park area. It seems about half occurred to the west, along the WRSZ (West Rainier Seismic Zone), and the other half occurred under the summit. The largest earthquake to strike Mt. Rainier during June was a M1.4 at 6.5km in depth on June 3, 2019 at 3:09UTC. It struck to the southwest along the WRSZ. Below are seismic plots detailing the largest event of June:

Please CLICK HERE to visit the USGS EQ map for this location and time period.

During the month of June 2019, Mt. St. Helens in Washington State saw a large increase in small-magnitude seismicity. After being very calm for some time, Mt. St. Helens surprisingly witnessed 86 reported earthquake events for the month of June. That is only the amount that was reported and it is likely a few other small earthquakes occurred. The majority of this month's seismicity occurred under the eastern edge of the summit.

Although the amount of seismicity increased greatly, the largest event for the whole month was a M1.4 at 4.1km in depth on June 30, 2019 at 15:31UTC. It struck directly under Mt. St. Helens' summit. Below are seismic plots of this event:

Please CLICK HERE to visit the USGS EQ map for this location and time period.

During the month of June 2019, only 1 single earthquake was reported for Mt. Hood. It was a M1.4 at 0.0km in depth (sea level) on June 21, 2019 at 22:33UTC. It struck directly under the western portion of Mt. Hood's summit. Below are seismic plots showing this earthquake:

Please CLICK HERE to visit the USGS EQ map for this location and time period.

During the month of June 2019, only 1 single earthquake was reported for Mt. Shasta. This is no surprise, seeing both Mt. Shasta and Mt. Hood are usually extremely calm. The largest and only earthquake reported for Mt. Shasta for June was a M0.6 at 3.1km in depth on June 25, 2019 at 23:57UTC. It struck under Mt. Shasta's NE base. Below are seismic plots of this event:

Please CLICK HERE to visit the USGS EQ map for this location and time period.

During the month of June 2019, Lassen Volcanic Center saw 9 reported earthquakes. Now, this month was extremely interesting. Why? Because the largest event of the month was a good sized low frequency earthquake. Low frequency earthquakes can be caused by magma itself, however it usually is associated with magmatic gasses.

I made sure this was not an algorithmic issue regarding teleseismic signatures from global earthquakes. The results are in and it was definitely a low frequency event, very similar to the ones Newberry Caldera has been seeing for the past few years. So, the largest reported event for Lassen Volcanic Center for the month of June 2019 was a M1.7 low frequency earthquake at 15.7km in depth on June 11, 2019 at 11:03UTC. It struck just barely west of Lassen Volcanic Center, although still within the volcanic center perimeter. Below are the seismic plots detailing this awesome volcanic earthquake:

Then, about 28 hours after the M1.7 low frequency earthquake, yet another volcanic event was detected on nearby stations around Lassen Volcanic Center. It was reportedly a M0.4 low frequency event striking at 9.9km in depth just to the NW of the original M1.7 (seismic plots shown below of the M0.4). Coincidentally, June 11-12, 2019 was a time period of increased seismic activity for California and Nevada. It sure was cool to see these volcanic earthquakes!