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Kīlauea Report: Magma Intrudes, Alert Raised to Watch/Orange

2:06 AM · Aug 25, 2021

An earthquake swarm is ongoing near Kīlauea's summit within Hawaiʻi Volcanoes National Park and “may indicate an intrusion of magma occurring 1-2 km (0.6-1.2 mi) beneath the south caldera” according to the USGS Hawaiian Volcano Observatory. While there are no signs of lava on the surface, magma movement continues underground at a rate exceeding 10 small earthquakes per hour, and the USGS has raised the volcano alert level/aviation color code to Watch/Orange in response. The activity poses no current threat to people, occurring entirely within the National Park away from any infrastructure. Today's USGS Volcano Activity Notice reports over 140 quakes were recorded between 4:30pm yesterday and 4:30am today, “with a particularly strong sequence … at about 1:30am HST” including the largest event at a reviewed magnitude 3.4. As of 3 pm, the IRIS earthquake catalog shows over 250 events, with only 29 exceeding magnitude 2, including the single magnitude 3. According to the USGS monitoring webpage, the large majority are tightly constrained between depths of sea level and 2 km (1.2 mi) below sea level, while for comparison, the south caldera magma chamber is thought to be situated between 2 - 4 km (1.2-2.5 mi) below sea level, and the recent lava lake surface sits at around 750 m (0.5 mi) above sea level. Speaking of the recent eruption, it was also preceded by an intrusion and swarm of over 220 earthquakes over 24 hours on December 2nd, 2020, with the largest a magnitude 3.1. In that singular case, it took another 18 days for the lava to emerge, after which the eruption continued for 5 months, with the last lava visible on Kīlauea on May 23rd. As a full three months have since elapsed, following the current scientific standard its most recent eruption might now be declared over. The guideline exists because volcanoes can “pause” their eruptions and then “resume eruption” if lava re-emerges nearby within 90 days, as happened numerous times during the 35-year Puʻuʻōʻō eruption. If the current uptick in activity leads to a nearby eruption shortly after the arbitrary deadline, perhaps an exception would be considered, otherwise the next emergence of lava will be classified as a new eruption regardless of its location and timing. At the time of writing, magma is still actively intruding underground in the newly cracked area beneath the south caldera, and it remains unclear if this will lead to further activity including the possibility of an eruption. The intrusion’s inflationary signal continues at a rapid rate, most evident on the tiltmeter at Sand Hill, but localized to the near-summit region, with a marked decrease in seismicity on the volcano’s East Rift Zone, while the south flank continues to adjust at its steady rate. We will continue to watch, report and relay information from the USGS as the situation develops, and finally, must restate that there is no increased volcanic threat to our island communities at this time. --- To support our productions please like, share and subscribe! Mahalo! Join our weekly live video review of Kīlauea and Maunaloa volcanoes, at 5pm Hawaiʻi time Thursdays! To support our productions please like, share and subscribe! Mahalo! #Kilauea2021 --- More information: https://www.usgs.gov/center-news/usgs-hvo-volcanic-activity-notice-yellowadvisory-status-change-orangewatch

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