Nov. 2019 - Spasmodic Tremor Update

12/1/2019

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...

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.

Comparison of Nov. 25, 2019 to Nov. 28, 2019; only 3 days.

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.

usgs eq map of reported nov. 2019 seismicity

hawaii seismic station map

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

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

Event 2

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

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

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.