 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... 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.  Stations I will use for all plots in this post that pertain to spasmodic tremor. 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! July 19, 2019 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 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 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 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 Event 2 occurred at 07:35UTC and lasted approximately 21 minutes. Event 3 Event 3 occurred at 11:39UTC and lasted approximately 30 minutes. Event 4 Event 4 was the last spasmodic tremor of July 27, 2019. It occurred at 12:52UTC and lasted approximately 30 minutes. Some larger magnitudes lately...  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):  At Kilauea summit: M3.0 at -0.8km in depth, with a M2.7 at -0.6km in depth just a few seconds prior.  Very near to Pu'u 'O'o: M3.0 at 6.2km in depth.  Mauna Loa upper part of SW rift zone: M3.1 at -0.9km in depth.  Kilauea summit: M3.0 (originally M3.6) at 0.0km in depth. This signature is vastly different from many of the other quakes in this area. It is very similar to the eruption signatures from 2018. Although an explosive eruption did not occur on July 26, 2019, it is possible this was due to magma encountering groundwater (the reason Kilauea saw explosive eruptions in 2018).  Mauna Loa upper part of SW rift zone: M3.3 (originally M3.5) at -1.1km in depth. A few people did report feeling this event.
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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. Archives
February 2020
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