Maunaloa volcano (Hawaiʻi): Swelling slowly continues, no significant change
ven, 16 apr 2021, 18:2018:20 PM | AUTORE: PO
This InSAR interferogram shows the overall inflation of Mauna Loa’s summit that occurred from November 2020 to March 2021. It also shows several fringes (color cycles) consistent with subsidence inside Moku‘āweoweo caldera and related to a shallow earthquake that was recorded on March 6, 2021. The red circles show the locations of earthquakes associated with that event as determined by HVO’s seismic network. (Image: USGS-HVO)
Unlike her neighbor Kīlauea to the south, Maunaloa is not erupting, and yet has been arguably more visible in the mainstream news this past month.
Recent summit view of Maunaloa with traces of recent snowfall, captured April 15, 2021 from USGS-HVO's webcam. (Image: USGS-HVO)
While a combination of earthquake clusters and an article on preparedness have drawn attention to the volcano, its monitored status and alert level remains unchanged with “no significant change in deformation rates or patterns that would indicate increased volcanic hazard at this time”, according to the USGS Hawaiian Volcano Observatory.
Last week on Maunaloa:
-GPS distance across summit switches from contraction to extension
-Ground tilt shows a small, but similar change
-No SO2 emissions, fumarole temperatures stable below 100 degrees C / 212 deg F
-220 small-magnitude earthquakes, all less than M2.5, 188 of them below the summit and upper-elevation flanks at depths of less than 8 km / 5 mi below ground level
-Earthquakes spike 1 week ago on April 9 with ~70 events, otherwise all days since show background levels below ~30 events per day
Discussion: Monitoring signals and recent InSAR imagery suggest that magma continues to fill slowly underground, triggering the observed seismic adjustments on Maunaloa's flanks over the past few weeks. Cycles of summit filling and flank adjustment are common on the volcano, and a switch back to the filling phase is consistent with GPS data. There is potential for the resumption of shallow seismicity around the volcano's summit, along with some reduction of flank adjustment earthquakes in the short term, until the cycle repeats. For now, the deformation rates are not indicative of any rapid or imminent change on Maunaloa.
Join our live video review of Maunaloa signals! Broadcast at 5pm HST Fridays and archived, along with short video updates, at the HawaiiPODD channel - including monitoring signals, photos & videos, time-lapses, geologic context and annotation, and discussion of live viewer questions.
Wed, 31 Mar 2021, 10:59
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Fri, 19 Mar 2021, 08:33
The Hawaiian Volcano Observatory (HVO) reported that a swarm of small earthquakes occurred at 15:46 local time yesterday beneath the southeastern flank of Mauna Loa volcano and northwestern summit of Kilauea volcano at zone known as upper Ka'ōiki. ... Read all
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