Well it has been more than a week since the last burst of spasmodic tremor, formerly called deep long period high frequency events by myself. Last night there was a very quick resurgence of spasmodic tremor, occurring in the same location and depths as many of the other ones have since January 2019. I will show a bunch of data pertaining to these events. Seismic audio is also included for the 5 spasmodic tremor events that occurred in Hawaii on June 1, 2019. Hope you enjoy! As always, if you haven't done so already, please click the title of this post or "read more" to continue...
On June 1, 2019, five spasmodic tremor episodes struck the Big Island of Hawaii. In this post I will detail the five events using data obtained from all four seismic stations labeled on the map above. Seismic audio of each event is also included. To see reported seismicity for this day and during June 1, 2019, please CLICK HERE. Notice how, at least right now, these spasmodic tremor events are being reported as normal earthquakes for this day. Of course some earthquakes do occur as part of these events, but the tremor episodes themselves are NOT normal earthquakes. Sometimes USGS labels these as "Other Event", seeing that is the best way to describe them in their catalog.
As usual, these events were pretty strong and were detected on seismic stations all across the Big Island. Prior to my post before this one, I used to call these events DLP-HFEs (deep long period, high frequency events). However, I finally discovered some other research about these events in other locations of the world. Their correct name is "spasmodic tremor". In the case of the recent Hawaiian spasmodic tremor, these events are volcanic in nature. I consulted with a couple seismologists regarding these events and it seems almost certain that these are signaling mass magma transport either ascending or descending along the mantle plume conduit that feeds volcanoes on the Big Island.
These events usually have mid-range frequencies, are rarely felt by humans, can last anywhere from 15 minutes to over 1 hour, and usually occur between 20km and 50km in depth. Again, the location and depths of these events confirm they are occurring within the mantle plume conduit. These events are actually showing us that Hawaii is still very volcanic and is getting ready for the next eruption. I don't know when that will be, but my guess is Mauna Loa will be the next volcano to erupt.
Here are some helicorders from the 4 stations labeled on the map above. Notice how they look like some serious surface events? Well they are not! Check it out:
Above you can notice 5 distinctly separate events, with 4 occurring in very close proximity to one another. Below I will detail all 5 events. For each event I will provide seismograms correlating these events on the four stations labeled on the map in the beginning of this post. After that I will provide 3-plot images from each of the four stations and will also provide seismic audio. Enjoy!
This blog is specifically for activity that occurs in Hawaii. In light of 2018's eruptions on the Big Island, I felt it necessary to have a section entirely devoted to events in Hawaii. I now mostly use this blog to update people on volcanic spasmodic tremor which occurs deep within the mantle plume conduit(s) under Pahala, HI. Don't know what spasmodic tremor is? Don't fret! Simply go to the Hawaii menu and click the page about Hawaii Spasmodic Tremor.