In this post I wanted to quickly show data and information pertaining to a certain event that happened at about 23:23UTC on Feb. 5, 2020. Please click the title of this post or "read more" to continue...

First off, over the past week or so there has been quite an increase in seismicity around Kilauea, Mauna Loa, the Kilauea LERZ, and the mantle plume conduit(s) under Pahala, HI. I recently made a post about this detailing some of those events and past spasmodic tremor over the past few months. Please CLICK HERE if you wish to view that detailed post.

On February 5, 2020 at 23:23UTC, a M2.8 earthquake struck just beneath the caldera floor at Kilauea at -0.1km in depth, reportedly. I first thought nothing of it, but decided to check the waveform/frequency content of this event.

I downloaded data from station CPKD, one of the stations shown on the map above. I use that station frequently to monitor the waveforms of earthquakes that occur under Kilauea, since it is only a mile or so from the caldera and frequency attenuation should not be a problem. I was surprised to see some really low frequencies associated with most of the event, signaling this was likely a hybrid earthquake

Then I downloaded data from all six stations shown in the map above. To my surprise, stations BYL, HAT, and SBL, the stations closest to the epicenter, showed a quick burst of high frequencies, also with an unnaturally long coda (end tail of an earthquake). Here is why I was perplexed:

Frequencies attenuate with distance, meaning the further from the epicenter you are the lower the frequencies will be from that same event. For high frequencies, say around 25Hz, to diminish to mainly low frequencies, say 5Hz and below, it would take many, many miles. Stations only a couple of miles away showed mainly low frequencies, especially OTLD and CPKD, and stations directly at the epicenter saw much higher frequencies within the initial burst, but with an unnaturally long end tail.

Basically, the frequencies of this event should not have dropped so dramatically over such a short distance of a couple miles. Why is this? Well, in my opinion, this signature is very similar to the volcanic eruption signatures that occurred at Kilauea during the 2018 eruptions (CLICK HERE to visit my Hawaii 2018 eruption page which shows a few examples of what the eruption signatures looked like). There was no eruption on this day, but it is very possible a small amount of magma encountered a small groundwater pocket and "exploded". This could explain why there was such a long coda, why frequencies dropped so dramatically within a short distance, and why it occurred so shallow. But who knows, I am only an amateur.

Below are the seismogram plots from the six stations shown on the map above. The plots are placed in order from the closest station shown at the top of the image. Note how dramatic the frequency attenuation was over such a short distance.

And here we have the spectrogram plots from those same six stations (note the very long coda):

Quakes, spasmodic tremor, and continued deformation is the name of the game during these past two months. Spasmodic tremor continued to decline in December 2019 and January 2020. There was even an increase in swarming and M3+ earthquakes late-January. Please click the title of this post or "read more" to continue...

As seen in the picture above, a pond of water larger than a football stadium has been constantly growing at the bottom of Halema’uma’u crater inside of Kilauea Caldera. It was originally thought to be rainwater, but USGS/HVO now confirms this intrusion is deeply rooted in groundwater. This could possibly spell trouble for Kilauea in the future. Sulfur dioxide is actively dissolved in the lake making accurate SO2 readings for rising magma extremely difficult.

To keep an eye on this growing lake, keep checking the Volcano Watch articles put out by HVO which can be found HERE. Also, you can keep an eye on it yourself if you monitor the webcams at Kilauea which can be found HERE. Picture and video updates from HVO can be found HERE (< that's my favorite way to monitor the growing lake). If you click a certain webcam you can see a time lapse of the past 24 hours.

Please click the USGS earthquake map button directly above. There were 1,053 reported earthquakes from Dec. 1, 2019 through Jan. 31, 2020 for the entire island chain of Hawaii. In those two months, ~75% of the reported earthquakes occurred deep under Pahala, HI within the mantle plume conduit(s), right where spasmodic tremor occurs. Speaking of spasmodic tremor...

Notice those deep earthquakes (25km to 60km depth) under Pahala, Hawaii? Well, those are occurring within the mantle plume where spasmodic tremor has recently been prevalent. If you wish to understand what volcanic spasmodic tremor is, and how it relates to ongoing volcanic unrest in Hawaii, please CLICK HERE.

Before I get to showing spasmodic tremor for December 2019 and January 2020, I wanted to quickly notify you about an increase in seismicity which started on January 29 and continues to the time I am writing this, 08:07UTC Feb. 3, 2020, though in diminished form.

Spasmodic tremor over the past 7 months has slowly been replaced by earthquake swarms for the same hypocenters as the spasmodic tremor events I have widely talked about and shown data for. Deep swarming within the mantle plume conduit(s) under Pahala, HI are nothing new since the eruptions on the Big Island stopped in Sept. 2018. However, January 29, 2020 saw quite an interesting increase in seismicity coupled with an increase in high M2s and some M3s in the shallow crust around Kilauea and the Lower East Rift Zone.

It is interesting to note many earthquakes ranging from M2.9 to M4.2 started striking around the Big Island volcanoes during this time range of increased deep seismicity under Pahala, HI, showing there must be a connection in some way of the deep magmatic processes occurring within the mantle plume conduit(s), which feed the volcanoes on the Big Island, and activity that occurs in the more shallow portions of the crust around Kilauea and the LERZ.

Just a few of the larger earthquakes during that time frame are shown below (CLICK HERE to see the USGS EQ map of Hawaii for Jan. 29, 2020 through Feb. 4, 2020; map will be automatically updated if it isn't Feb. 4 yet):

-M4.2 at 7.7km depth on Feb. 3, 2020 at 06:37UTC ~9.5km SE of Kilauea and 10km SW of Pu‘u ‘Ō‘ō (over 300 felt reports; largest earthquake on Big Island since the deep M4.9 at Mauna Kea on November 11, 2019 and the largest at Kilauea/LERZ since the M5.5 at 7.0km depth on March 13, 2019 which struck basically in the same location)

-M3.8 at 5.5km depth on Jan. 29, 2020 at 22:23UTC ~18km ESE of Pu‘u ‘Ō‘ō along the coast (73 felt reports)
-M3.2 at 31.7km depth on Feb. 1, 2020 at 22:33UTC under Pahala, HI within mantle plume conduit
-M3.0 at 7.2km depth on Jan. 30, 2020 at 11:51UTC just south of Pu‘u ‘Ō‘ō (4 felt reports)

-M3.0 at 32.0km depth on Feb. 1, 2020 at 13:48UTC under Pahala, HI within mantle plume conduit
-M3.0 at 3.0km depth on Feb. 1, 2020 at 13:48UTC just a few km south of Pu‘u ‘Ō‘ō and struck at the same time as the quake listed directly above

Of course M3.0 earthquakes are nothing to worry about and are not major by any standard. However, M3+ quakes rarely have struck the Big Island for many months now, especially the recent M4.2. When we see an increase in seismicity within the mantle plume conduit(s), coupled with an increase in higher magnitude earthquakes in the shallow crust, we must see there is some correlation. The exact correlation still eludes me to this day.

The helicorder plots in slideshow format below show quakes from 13:00UTC Jan. 29, 2020 to 10:05UTC Feb. 2, 2020. 136 quakes were reported during this time frame for the Big Island. Of course, some were not able to be located accurately so this count is likely slightly higher. However, 88 quakes were reported in the deep mantle plume conduit(s) beneath Pahala where spasmodic tremor occurs. That means over 75% of the recent increase in seismicity, and the earthquakes you see on the helicorders below, occurred within the mantle plume conduit(s).

Helicorder plots were filtered with a 1.1Hz high pass filter and were retrieved using the IRIS TimeSeries tool. Whenever the location code is --, and the data is downloaded from the TimeSeries tool, a glitch occurs on the helicorder plots where the location code is shown as -12345, as seen below. I am unsure why this glitch occurs.

Here are seismogram plots from the six closest stations to the M4.2 that occurred on February 3, 2020:

Here are the spectrogram plots from the same stations listed above of the M4.2:

Now, let's get to all spasmodic tremor events which occurred for both December 2019 and January 2020. Remember, seismic audio is included beneath the plots. An 8,000 audio frame rate (samples per second) was used to increase the speed greatly of the audio to allow for easy listening to each spasmodic tremor event. The IRIS TimeSeries tool was used to retrieve this seismic audio from station PPLD and the IRIS DataSelect tool was used to retrieve the seismic data.

This spasmodic tremor occurred on December 7, 2019 at 14:05UTC. It was weak lasted a mere ten minutes, which is the shortest spasmodic tremor I have encountered.

This spasmodic tremor occurred on December 18, 2019 at 19:20UTC. Again, it was weak and lasted only ten minutes.

Spasmodic tremor occurred on December 18, 2019 at 21:22UTC. It was so weak I almost missed it and it lasted only 19 minutes.

Spasmodic tremor occurred on December 29, 2019 at 09:08UTC. It was weak and lasted 36 minutes. The earthquakes that you can see may or may not be related to the spasmodic tremor of this day.

Spasmodic tremor occurred on Dec. 29, 2019 at 09:48UTC. It was the strongest of December 2019 and January 2020 and lasted 36 minutes.

Happy New Year!!! Spasmodic tremor occurred on Jan. 16, 2020 at 18:44UTC. It was extremely weak and I almost missed it. This tremor lasted only 19 minutes.

Spasmodic tremor occurred on Jan. 17, 2020 at 06:57UTC. It was arguably the 2nd strongest spasmodic tremor of December 2019 - January 2020 and lasted 30 minutes.

Spasmodic tremor occurred on January 29, 2020 at 10:45UTC. It was sort of weak but surprisingly lasted 40 minutes.

As for the past few months, spasmodic tremor has continued to decline. Regardless, we are still seeing a good sized spasmodic tremor event once per month. I will continue doing monthly spasmodic tremor updates until they increase or die off altogether. As usual, please click the title of this post or "read more" to continue...

Also, as seen in the picture above, a pond of water larger than a football stadium has been constantly growing at the bottom of Halema’uma’u crater inside of Kilauea Caldera. It was originally thought to be rainwater, but USGS/HVO now confirms this intrusion is deeply rooted in groundwater. This could spell trouble for Kilauea in the future. Sulfur dioxide is actively dissolved in the lake making accurate SO2 readings for rising magma extremely difficult.

To keep an eye on this growing lake, keep checking the Volcano Watch articles put out by HVO which can be found HERE. Also, you can keep an eye on it yourself if you monitor the webcams at Kilauea which can be found HERE. If you click a certain webcam you can see a time lapse of the past 24 hours.

If you wish to understand what volcanic spasmodic tremor is, and how it relates to ongoing volcanic unrest in Hawaii, please CLICK HERE.

Spasmodic tremor has been quite minimal lately with only a few events occurring per month. When spasmodic tremor somewhat started to calm a few months ago, it was replaced by an increase in seismicity in the same hypocentral location. I am unsure why this is, but hopefully someday we will find out.

Here are the spasmodic tremor events for Hawaii during November 2019. Sadly, station TRAD, my favorite station in Hawaii for viewing spasmodic tremor, went offline mid-November. I will use station PLAD when TRAD is not available.

Remember, spasmodic tremor can appear as surface events. Regardless of the appearance of an event, it is truly seismic in nature if it appears on multiple stations many miles away. Therefore I have posted a map of the stations I use in this post. You can also check out the Hawaii station map button above.

As usual, I will include seismic audio from station PPLD for the spasmodic tremor events below. Some events are so weak you may not be able to hear them (8,000 samples per sec). All seismic audio is sped up to allow the frequencies to be heard and all audio is retrieved from the IRIS database. Although the audio may only last 10-30 seconds, the actual events could last many minutes!

Event 1 occurred at 21:09UTC on November 7, 2019. It was extremely weak and lasted only 17 minutes.

Event 2 occurred at 06:50UTC on November 9, 2019. It was so weak that is was barely detectable on nearby stations. Regardless, it still did occur and lasted only 10 minutes or so.

Event 3 occurred at 17:09UTC on November 14, 2019. It was definitely the strongest spasmodic tremor of November 2019 and lasted approximately 29 minutes.

Event 4 occurred at 18:15UTC on November 14, 2019, just after the largest spasmodic tremor of November. It was the second largest of November and lasted approximately 40 minutes.

Event 5 occurred at 17:57UTC on November 20, 2019. It was the third strongest spasmodic tremor of November and lasted approximately 39 minutes.

Spasmodic tremor continues to weaken and be replaced by high frequency earthquakes. As spasmodic tremor diminishes from its original stature, I believe high frequency earthquakes will continue to occur in swarms in the same location and depth as spasmodic tremor. This is the current pattern that is occurring and could change at any moment. Nevertheless, there were 4 spasmodic tremor events from Oct. 16 - Oct. 31. Please click the title of this post or "read more" to continue...

As seen in the picture above, a pond of water has been constantly growing at the bottom of Halema’uma’u crater inside of Kilauea Caldera. It was originally thought to be rainwater, but USGS/HVO now believes it is highly likely this is groundwater. This could spell trouble for Kilauea in the near future. To keep an eye on this growing pond, keep checking the Volcano Watch articles put out by HVO which can be found HERE. Also, you can keep an eye on it yourself if you monitor the webcam at Kilauea which can be found HERE.

If you wish to understand what volcanic spasmodic tremor is, and how it relates to ongoing volcanic unrest in Hawaii, please CLICK HERE.


Strong spasmodic tremor in October continues to elude us. There were only 4 spasmodic tremor events from Oct. 16 - Oct. 31, 2019. One event was somewhat strong for spasmodic tremor, but still does not come close to the ones we have seen since Jan. 23, 2019.

Regardless, I still like to keep a "log" of sorts regarding spasmodic tremor since these events do fascinate me. Below I will show the seismogram and spectrogram of each spasmodic tremor within the stated date range above. Each long image will contain those plots from 3 seismic stations around the Big Island.

After the plots for each event are shown, I will include seismic audio as usual. Seismic audio is retrieved using the IRIS Time Series resource and each audio clip's speed is highly increased.

Spasmodic tremor occurred on October 16, 2019 at 10:22UTC. It was weak and lasted approximately 24 minutes.

Spasmodic tremor occurred on October 22, 2019 at 15:39UTC. It was the strongest of October and lasted approximately 37 minutes. Note there were no observable earthquakes during this event except near the end. This event was basically all tremor with little to no earthquakes.

Spasmodic tremor occurred on October 23, 2019 at 05:16UTC. It was very weak and lasted approximately 23 minutes.

Spasmodic tremor occurred on October 24, 2019 at 13:15UTC. It was weak and lasted approximately 38 minutes.

There were only 4 spasmodic tremor events from Sept. 1 through Oct. 9, 2019. This is far less than the preceding months and could signal a weakening in the spasmodic tremor sequence we have been witnessing since Jan. 23, 2019. However, deep seismic activity seems to be increasing as the spasmodic tremor decreases. Could the tremor be in the process of being replaced by normal earthquakes? Only time will tell. Please click the title of this post or "read more" to see spasmodic tremor for the time period stated above...

Mauna Loa is currently experiencing heightened volcanic unrest, including increasing seismicity and uplift. Therefore, the alert level has been raised to ADVISORY and the aviation color code has been raised to YELLOW. Please CLICK HERE to keep up to date with recent alert postings by USGS/HVO for Mauna Loa’s potential eruptive activity.

Also, as seen in the picture above, a pond of water has been constantly growing at the bottom of Halema’uma’u crater inside of Kilauea Caldera. It was originally thought to be rainwater, but USGS/HVO now believes it is highly likely this is groundwater. This could spell trouble for Kilauea in the near future. To keep an eye on this growing pond, keep checking the Volcano Watch articles put out by HVO which can be found HERE. Also, you can keep an eye on it yourself if you monitor the webcam at Kilauea which can be found HERE.

First off, if you wish to understand what volcanic spasmodic tremor is, and how it relates to ongoing volcanic unrest in Hawaii, please CLICK HERE.

From Sept. 1 through October 9, 2019, there were over 605 earthquakes under the Big Island of Hawaii. Swelling of the ground continues, from an influx of magma from depth, at the Mauna Loa summit, the Kilauea summit, and the Kilauea East Rift Zone.

Spasmodic tremor was almost eerily silent during this time period with only 4 spasmodic tremor events. That is extremely low and all were very weak. It seems deep seismicity is now replacing deep spasmodic tremor. October 4, 2019 saw only one spasmodic tremor but it was the strongest of the past month or two.

Below I will show the usual seismogram and spectrogram plots of the 4 spasmodic tremor events from Sept. 1 through October 9, 2019. They will be shown from 3 stations: PPLD, TRAD, and HUAD. Seismic audio will be included after each event. Seismic audio was obtained from station PPLD through the IRIS Time Series webservice. Speed of the audio has been increased greatly to hear the seismic events in question.

Event 1 occurred on Sept. 3, 2019 at 22:33UTC and lasted approximately 36 minutes. This spasmodic tremor was extremely strange looking. Two earthquakes struck somewhere on the island during this time frame, as can be seen below.

Event 2 occurred on Sept. 26, 2019 at 17:12UTC. It lasted around 21 minutes.

Event 3 occurred on Sept. 26, 2019 at 23:15UTC. It lasted around 27 minutes and was so weak it was almost unnoticeable.

Event 4 occurred on October 4, 2019 at 18:34UTC. It lasted approximately 15 minutes, though it was hard too tell since it diminished slowly. This was by far the strongest spasmodic tremor since Sept. 1, 2019.

Hey guys! In this post I will show some quick data pertaining to an energetic swarm that broke out under Pahala, Hawaii, recent spasmodic tremor, and a deep M4.2 under the Loihi Seamount off the coast of Hawaii. Please click the title of this post or "read more" to continue...

Mauna Loa is currently experiencing heightened volcanic unrest, including increasing seismicity and uplift. Therefore, the alert level has been raised to ADVISORY and the aviation color code has been raised to YELLOW. Please CLICK HERE to keep up to date with recent alert postings by USGS/HVO for Mauna Loa’s potential eruptive activity.

Also, as seen in the picture above, a pond of water has been constantly growing at the bottom of Halema’uma’u crater inside of Kilauea Caldera. It was originally thought to be rainwater, but the fact that it is constantly growing with the lack of enough rain does point to the rising of the water table. This could spell trouble for Kilauea in the near future. To keep an eye on this growing pond, keep checking the Volcano Watch articles put out by HVO which can be found HERE. Also, you can keep an eye on it yourself if you monitor the webcam at Kilauea which can be found HERE.

Now, if you wish to understand what volcanic spasmodic tremor is, and how it relates to ongoing volcanic unrest in Hawaii, please CLICK HERE.

Starting primarily on August 18, 2019, a deep earthquake swarm broke out under Pahala, Hawaii. Coincidentally, the location and depth of this swarm indicates it is likely occurring where spasmodic tremor occurs: within the mantle plume conduit.

The depths of the earthquakes in this swarm ranged from 30km to 50km in depth and the largest reported event of the swarm was a M3.2 event at 35.7km in depth. Although only 112 earthquakes were reported, it is likely over 200 actually occurred as part of this swarm. The swarm is still ongoing at the time of writing this (August 25, 2019 at 01:41UTC), however it has diminished substantially. Most of the swarm occurred between August 18 and August 23.

Station TRAD was one of the best stations in the area to detect these events. Check out how many earthquakes there are! Almost every earthquake you see struck deep under Hawaii within the mantle, right where spasmodic tremor occurs. Some spasmodic tremor can also be seen on the helicorders below. Can you spot them? Below are helicorders in slideshow format from TRAD:

Now, I will quickly show some seismic plots of random events as part of this swarm. Since station TRAD is one of the better stations to detect these events, I will use that station for the plots below. I do not show every single earthquake in this swarm, but I do show around 20 of them. Times are in UTC of course. So, if you wish to see how large these were, or if any were reported, please check the USGS EQ map button in the beginning of this post and compare the times.

Although seismicity skyrocketed for the location of where spasmodic tremor occurs, spasmodic tremor itself was almost non-existent for the week of 8/18 through 8/24. For that whole week there were only 3 minor events and 1 moderate event. I will show those now, along with the usual audio.

The seismic audio you hear was taken from station TRAD, one of the best stations to use for monitoring spasmodic tremor. Also, the audio is sped up to allow it to be heard better. All audio is taken from IRIS and I suggest using headphones! However, be wary of the audio just in case!

Event 1 occurred on August 21, 2019 at 04:56UTC. It was very minor and lasted approximately 24 minutes.

Event 2 occurred on August 21, 2019 at 06:40UTC. It was very minor and lasted around 24 minutes. How come spasmodic tremor sometimes lasts around 24 minutes? Strange...

Event 3 occurred on August 21, 2019 at 09:18UTC. It was minor and lasted approximately 32 minutes.

Event 4 occurred on August 23, 2019 at 10:20UTC. It was moderate and lasted around 48 minutes.

On August 22, 2019 at 14:33UTC a M4.2 earthquake struck under the southern flank of the Loihi Seamount at 46.0km in depth. The M4.2 under Loihi is the largest to strike near or under the Big Island since the M4.5 under Hilo Bay on August 12, 2019. This recent M4.2 under Loihi is also the largest to strike the seamount since the M5.3 struck at 40.3km in depth to the east of Loihi on June 5, 2013.

Well, the Big Island of Hawaii never ceases to amaze. Not only are the wildlife and plants abundant in diversity, but so are the volcanoes! Many different aspects of volcanic activity continue to take place under, and on, the Big Island of Hawaii.

Spasmodic tremor continues sporadically, though rates seem to have dropped over the past several weeks. This does occur from time to time and magma continues to pour into the Mauna Loa summit, Kilauea summit, and Kilauea East Rift Zone reservoirs.

There were also two earthquakes I will quickly mention in this post: a very strange M4.5 in Hilo Bay and a M3.2 under Mauna Kea. Also, if you haven't heard, a pond/lake is growing at the bottom of Halema'uma'u Crater inside of Kilauea Caldera. It is not a lava lake, but in fact a lake or pond of water. It was discovered on July 25, 2019 and was originally thought to be rain water. However, recent studies indicate that the pond is constantly growing and that recent rainfall has been minimal. Basically, it appears that groundwater is intruding into the crater, seeing that rainfall has been insufficient to create a constantly growing pond. Regardless, either groundwater or rainfall could be the cause. Either could be true, but the research done by HVO/USGS points more favorably toward groundwater. This could cause explosive eruptions in the near future if certain conditions have been met. And according to USGS/HVO, this type of situation has occurred at Kilauea before. 

Please click the title of this post or "read more" to continue...

Mauna Loa is currently experiencing heightened volcanic unrest, including increasing seismicity and uplift. Therefore, the alert level has been raised to ADVISORY and the aviation color code has been raised to YELLOW. Please CLICK HERE to keep up to date with recent alert postings by USGS/HVO for Mauna Loa’s potential eruptive activity.

Also, as seen in the picture above, a pond of water has been constantly growing at the bottom of Halema’uma’u crater inside of Kilauea Caldera. It was originally thought to be rainwater, but the fact that it is constantly growing with the lack of enough rain does point to the rising of the water table. This could spell trouble for Kilauea in the near future. To keep an eye on this growing pond, keep checking the Volcano Watch articles put out by HVO which can be found HERE. Also, you can keep an eye on it yourself if you monitor the webcam at Kilauea which can be found HERE.

Also, if you wish to understand what volcanic spasmodic tremor is, and how it relates to ongoing volcanic unrest in Hawaii, please CLICK HERE.

Spasmodic tremor has not been too prevalent as of late. However, we did see multiple small events and one large event between August 12 through August 14. I will show the usual seismic data and audio pertaining to these events. Afterward, I will quickly talk about the two recent and interesting earthquakes that struck near Hilo and Mauna Kea.

Also, station WAID is a terrible station, but is one of the only short period channels in the location I need. Lots of weaker spasmodic tremor does not appear on there. So use primarily TRAD and KKUD to confirm is something is seismic, seeing those stations are many miles apart.

Below are helicorder plots in slideshow format which show all of the spasmodic tremor I will talk about today. Some are hard to see, but can be easily seen on station TRAD. However, using the seismic plots I am about to show, you can clearly see the events on 3 out of 4 stations.

Below I will show the usual seismogram, spectrogram, and spectra plots detailing the August 12-14, 2019 spasmodic tremor events. I will also include seismic audio from station PPLD which will allow you to hear all of the spasmodic tremor events. Regarding the seismic audio, it was obtained using the IRIS Time Series source. I suggest using headphones, but please be wary of loud volume just in case! All audio is always sped up to allow you to hear it better. Enjoy!

Event 1 occurred on August 12, 2019 at 12:45UTC. It was minor and lasted approximately 24 minutes.

Event 2 occurred on August 12, 2019 at 22:32UTC. It was barely noticeable and lasted approximately 22 minutes.

Event 3 occurred on August 13, 2019 at 00:22UTC and lasted approximately 24 minutes.

Event 4 occurred on August 14, 2019 at 09:27UTC. It was extremely minor and lasted approximately 27 minutes.

Event 5 occurred on August 14, 2019 at 09:58UTC. It was the largest event we have seen in a few weeks and lasted approximately 29 minutes.

In the past few weeks seismicity on the Big Island spikes and plummets periodically. However, we recently saw two very interesting earthquakes.

The first was a M3.2 at 18.8km in depth under the ENE base of Mauna Kea on August 11, 2019. Below are plots and the event page for this event. Over 38 people felt this earthquake.

Then, on August 12, 2019, a strong M4.5 earthquake struck deep at 42.0km in depth inside of Hilo Bay, a very strange location for an earthquake of this depth. This M4.5 was the strongest earthquake on the Big Island since the M5.3 at the Hualalai volcano on April 14, 2019.

Below are plots and the event page to this event. Over 413 people reported feeling this M4.5.

On July 19 we saw a pretty strong spasmodic tremor event in Hawaii. It was one of the strongest we have seen since January 23, 2019. Also, earthquakes continue to slowly increase at Kilauea and Mauna Loa, with magnitudes seeing a sharp rise just since July 21, 2019. In this post I will show the usual seismic data and audio to recent spasmodic tremor events. Afterward, I will show plots of the largest earthquakes on the Big Island we have seen as of late. Please click the title of this post or "read more" to continue...

If you wish to understand what volcanic spasmodic tremor is, and how it relates to ongoing volcanic unrest in Hawaii, please CLICK HERE.

First off, click the USGS EQ map button above to see all events reported by USGS for July 19 through July 27. Please keep in mind HVO at volcanoes.usgs.gov (under the monitoring tab, under “Data – Past Week” for each volcano) reports far more earthquakes than the USGS earthquake website does. Regardless, USGS does a great job at reporting most earthquakes associated with spasmodic tremor and most quakes above M2.0. Also, another button resides above to see the locations of all active seismic stations on the Big Island of Hawaii.

Well, spasmodic tremor has been somewhat quiet recently. On July 19, 2019, we saw a very large spasmodic tremor event. Then, on July 22, a very weak event was detected. It was quiet, regarding spasmodic tremor, until July 27, 2019. On July 27, 2019, the first spasmodic tremor event occurred since the 22nd.

A strong M3.5, now downgraded to M3.3, earthquake struck Mauna Loa during the first spasmodic tremor on July 27, 2019. Magnitudes of earthquakes in Hawaii, near Mauna Loa and Kilauea, have been steadily rising since about July 21, 2019. Pressure is just starting to reach a tipping point. I will show those earthquakes at the end of this post. For now, let's check out the recent spasmodic tremor events!

Below, along with the usual seismic plots, I will include seismic audio from station PPLD which will allow you to hear all of the spasmodic tremor events. Regarding the seismic audio, it was obtained using the IRIS Time Series source. I suggest using headphones, but please be wary of loud volume just in case! All audio is always sped up to allow you to hear it better. Enjoy!

There was only one spasmodic tremor on July 19, 2019. It was extremely strong, though not the strongest ever. It started at 13:59UTC and lasted about 43 minutes. You can clearly see it on the helicorder and seismic plots below.

July 22, 2019 saw only one lonely spasmodic tremor. It was extremely weak and barely noticeable on the helicorder plots below. However, if you look at the seismic plots from PPLD, TRAD, and KKUD, you can clearly see the event. This lonely tiny event occurred at 23:41UTC and lasted only 11 minutes.

July 27, 2019 saw a total of 4 spasmodic tremor events. They were pretty weak, but you can clearly see them within the seismic plots below. As for the helicorder plots below, you can basically only see them on PPLD and TRAD.

Event 1 occurred at 03:12UTC and lasted a shocking total of 1 hour and 9 minutes! The longest I have ever seen was 1 hour and 11 minutes long, so this one almost made it! The largest earthquake signature you see on the plots below is the M3.5 at Mauna Loa which occurred during this spasmodic tremor event.

Event 2 occurred at 07:35UTC and lasted approximately 21 minutes.

Event 3 occurred at 11:39UTC and lasted approximately 30 minutes.

Event 4 was the last spasmodic tremor of July 27, 2019. It occurred at 12:52UTC and lasted approximately 30 minutes.

Ever since July 21, 2019, it seems earthquakes above M3.0 are becoming more common. Of course M3.0 quakes are hardly significant, however prior to this date they have rarely occurred. Why the large burst all of a sudden? I believe it has to do with the pressure slowly reaching a tipping point. We may be far from that tipping point, but uplift continues at the Mauna Loa summit, the Kilauea summit, and the Kilauea East Rift Zone. Here are all the M3.0+ events that have occurred since July 21, 2019 (image captions included and all plots are from the closest stations to these events):

So, it seems volcanic spasmodic tremor in Hawaii is not stopping. Sometimes it doesn't occur for almost a week, however it seems to always return. Will we continue to see these until the next eruption in Hawaii (whenever that may be)? I think it is likely. As usual, please click the title of this post or "read more" to continue...

Mauna Loa is currently experiencing heightened volcanic unrest. For this reason, the alert level has been raised to ADVISORY and the aviation color code has been raised to YELLOW. Please CLICK HERE for additional updates from HVO as they are issued.

If you wish to understand what volcanic spasmodic tremor is, and how it relates to ongoing volcanic unrest in Hawaii, please CLICK HERE.

First off, click the USGS EQ map button above to see all events reported by USGS for this time period and location. Please keep in mind HVO at volcanoes.usgs.gov (under the monitoring tab for each volcano) reports far more earthquakes than the USGS earthquake website does. Regardless, USGS does a great job at reporting most earthquakes associated with spasmodic tremor. Also, another button resides above to see the locations of all active seismic stations on the Big Island of Hawaii.

During July 16, 2019 through July 18, 2019, a total of 6 spasmodic tremor events were detected under the Big Island of Hawaii in the usual location just south of Pahala, Hawaii. They were not too strong, but the event on July 16, 2019 was one of the strongest we have seen since January 23, 2019. I emphasize the phrase "one of the strongest", seeing there have been some pretty strong ones since then.

Below I will show the usual helicorder plots, seismogram, spectrogram, and spectra plots detailing these events from the four seismic stations labeled on the map in the beginning of this post. I will also include seismic audio from station PPLD which will allow you to hear all of the spasmodic tremor events. Regarding the seismic audio, it was obtained using the IRIS Time Series source. I suggest using headphones, but please be wary of loud volume just in case! All audio is always sped up to allow you to hear it better. Enjoy!

There was only one spasmodic tremor event detected on July 16, 2019. It started at 10:50UTC and lasted approximately 42 minutes. It can clearly be seen quite strong on all 4 stations. It was not the strongest ever, but is definitely near the top of the list!

Event 1 occurred on July 17, 2019 at 09:20UTC and lasted 1 whole hour!

Event 2 occurred on July 17, 2019 at 17:44UTC and lasted around 22 minutes.

Event 1 occurred on July 18, 2019 at 04:19UTC and lasted approximately 20 minutes.

Event 2 occurred on July 18, 2019 at 04:39UTC and lasted about 27 minutes.

Event 3 occurred on July 18, 2019 at 05:38UTC and lasted approximately 31 minutes.

Hey guys! In this post I am going to show the usual seismic plots and audio associated with the spasmodic tremor events in Hawaii for July 4-5, 2019. I will also detail a reminder about what spasmodic tremor is and what it is likely caused by in Hawaii. As usual, please click the title of this post or "read more" to continue...

Mauna Loa is currently experiencing heightened volcanic unrest. Alert level is currently ADVISORY and the aviation color code is assigned to YELLOW. Please CLICK HERE to keep an eye on future updates issued by the HVO.

First off, click the USGS EQ map button above to see all events reported by USGS for this time period and location. Please keep in mind HVO at volcanoes.usgs.gov reports far more earthquakes than the USGS earthquake website does. Regardless, USGS does a great job at reporting most, if not all, earthquakes associated with spasmodic tremor. Also, another button resides above to see all active seismic stations on the Big Island of Hawaii.

Ever since I discovered my first spasmodic tremor event in late-Jan. 2019 for the Big Island of Hawaii, I have been utterly fascinated by them. I first incorrectly called them "DLP-HFEs", deep long period high frequency events. Then, thanks to a a professional seismologist, I was notified of a few publications about seismic events including spasmodic tremor. It first peaked my interest when USGS started posting "diamonds", reporting them as "Other Event", instead of the normal circles which represent earthquakes on their USGS EQ map. Sometimes USGS reports spasmodic tremor as "Other Event" and other times they simply report them as earthquakes. These events are for more complicated than simple earthquakes.

Spasmodic tremor is a type of seismic event that is "spastic" and "erratic". Unlike volcanic tremor which can go on and on for days and even months, carrying dominant frequencies between 1-5Hz, spasmodic tremor can appear and disappear in a much shorter time frame. They can also occur in "swarms", which has been witnessed in Hawaii many times since January 23, 2019. In the case of Hawaii's spasmodic tremor, these seismic events are occurring within the mantle plume which feeds magma into local magma reservoirs on the Big Island. Thus the likely conclusion is that these events are signaling mass magma transport. I have also asked a seismologist about these events and it seems that is a likely conclusion. Here is a cross section showing part of the Big Island of Hawaii from HVO:

The cross section above shows the depth of the crust and upper mantle beneath Kilauea volcano. It shows a maximum depth of 15 miles, or about 24 kilometers. This proves that these spasmodic tremor events are occurring deep within the mantle, of course likely occurring within the mantle plume itself. Why? Well, here are some characteristics of spasmodic tremor I have noted in my research from seismic analysis and reported depths:

1. Depths can occur from about 20km to 60km in depth. However, most I have seen reported occur between 30km and 45km in depth.
2. Spasmodic tremor is NOT an earthquake. Sometimes spasmodic tremor is made of multiple earthquakes occurring extremely fast, and other times spasmodic tremor is more emergent (slowly builds) and is more tremor-like with a lack of earthquake "spikes".
3. Spasmodic tremor in Hawaii can last anywhere from 10 minutes to 1 hour and 11 minutes! 1 hour and 11 minutes is the longest spasmodic tremor I have detected since January 2019.
4. Spasmodic tremor usually occurs at those depths stated above, but most epicenters are situated under Pahala, Hawaii or just off the coast of Pahala.
5. It is hard to tell, but it seems that, at times, spasmodic tremor in Hawaii either becomes more shallow or deeper with time. Could this be signaling both the ascent and descent of magma within the plume?
6. To the untrained eye, it seems like these events are indicative of surface activity. On the contrary, most stations around the entire island detect these events quite well, even though the power detected during these events is usually not greater than what a M3.0 would release. We also know they are occurring at the likely depths they are being reported at, seeing there is not much of a leeway of P wave arrivals from station to station.
7. Spasmodic tremor usually carries mid-range frequencies with dominant frequencies sometimes occurring between 10-15Hz depending on the event. It cannot be considered a low frequency event.
8. Aseismic activity is pronounced at depths shallower than ~19km directly after most spasmodic tremor. If this is magma recharge, which is possible, why then is there a lack of seismic activity connecting the spasmodic tremor events within the conduit to the sub-surface reservoirs in the area?

So, we see spasmodic tremor in Hawaii is probably associated with mass magma transport along the mantle plume conduit which feeds many sub-surface magma reservoirs for many of the volcanoes on the island. One thing that is not clear, is something associated with the fact that spasmodic tremor is not constant. Magma must be feeding these volcanoes at an almost constant rate, especially when seeing the swelling some of the areas on the Big Island are currently showing. So why is it that we don't see this occurring all the time every day? Is it possible spasmodic tremor is signaling a "widening" of the mantle plume conduit in response to a larger amount of magma? I don't know. But this is why I love this field of work!

Below I will show some plots detailing the spasmodic tremor events that occurred under the Big Island of Hawaii on July 4-5, 2019. They were pretty weak compared to recent events, and didn't last long compared to some other days I have seen. Regardless, I always like to report on them when I see more than one in a 48 hour period. As usual, I will show helicorder plots first. BE WARY: Helicorders below have 48 hours allotted with 60 minutes per line (seismogram), instead of the usual 24 hours with 30 minutes per line (seismogram). So that means events might appear smaller than usual.

Below I will show the usual seismogram, spectrogram, and spectra plots detailing the July 4-5, 2019 spasmodic tremor events from the four seismic stations labeled on the map in the beginning of this post. I will also include seismic audio from station PPLD which will allow you to hear all of the spasmodic tremor events. Regarding the seismic audio, it was obtained using the IRIS Time Series source. I suggest using headphones, but please be wary of loud volume just in case! All audio is always sped up to allow you to hear it better. Enjoy!

Event #1 occurred on July 4, 2019 at 22:14UTC. It lasted approximately 25 minutes.

Event #2 occurred on July 5, 2019 at 01:49UTC. It lasted approximately 26 minutes.

Event #3 occurred on July 5, 2019 at 22:38UTC. It lasted approximately 25 minutes.