Oct. 16 - Oct. 31: Spasmodic Tremor Update

Spasmodic tremor as seen on station HUAD on Oct. 22, 2019.

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...

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.

The current water lake within Halema'uma'u continues to grow and is now the size of a United States football stadium.

usgs eq map of hawaii oct. 16 - oct. 31, 2019

hawaii seismic station map

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.

Event 1

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

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Event 2

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.

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Event 3

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

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Event 4

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