At 1:10 p.m. on Friday, seismicity in the southern part of the summit region of Kīlauea volcano on the Big Island began abruptly, and since then about 350 earthquakes have occurred at depths of .5 to 2 miles.
Most of the earthquakes have been a magnitude of 2.5 or less, according to the Hawaiian Volcano Observatory.
Earthquake swarms like this can precede eruptions, but an observatory update said there was no lateral or upward migration of earthquakes that would suggest magma is moving toward the surface.
The observatory said there are currently no signs of an imminent eruption. Seismicity has not reached the levels that immediately preceded recent Kīlauea summit eruptions.
The current seismicity followed a sharp increase in inflation recorded by the Sand Hill tiltmeter that began at 12:30 p.m. Friday, and continues today. The summit tiltmeter at Uēkahuna began recording slight deflationary tilt at about the same time.
There were more than 80 locatable earthquakes in the region throughout the following 6-hour period and many smaller earthquakes.
The increased seismicity began just to the south of Halemaʻumaʻu crater and has progressively included a larger region to the south of the caldera about 1 to 2.5 miles south of Halema‘uma‘u.
The area of the unrest has progressively widened to the southwest toward the Koʻae fault zone.
The current rate of earthquakes is slightly higher than what was seen in October during the unrest that accompanied the magma intrusion in the same area.
Earthquakes are continuing today in the region, with slight variations in rate and size.
Kīlauea’s summit region also remains at a high level of inflation. Relative tilt is above the level reached prior to the most recent eruption in September and is higher than at any time since the 2018 lower East Rift Zone eruption.
Periods of increased or decreased numbers of shallow earthquakes can be expected to continue during repressurization of the summit magma reservoir that has been ongoing since the end of the September eruption.
It is uncertain if this increased activity will lead to an eruption or another major intrusion of magma in this area; however, an eruption is possible with little or no warning.
The onsets of previous summit eruptions have been marked by strong swarms of earthquakes caused by magma moving toward the surface 1 to 2 hours before the appearance of lava. This type of earthquake activity is not being detected at this time.
No unusual activity has been noted along Kīlauea’s East or Southwest rift zones.
The current Volcano Alert Level remains at advisory.
The last eruption at Kīlauea summit ended Sept. 16 and was followed by a significant intrusion to the southwest of Kīlauea caldera. Seismicity has waxed and waned since, alternating between the southwest area, the south end of the caldera and the upper East Rift Zone.
Most recent seismicity has alternated between the summit caldera and the upper East Rift Zone.
A map of intrusive activity that happened in October is available here. A map summarizing the recent unrest around Kilauea’s summit, from Nov. 11 to Dec. 12, can be found here.
Hawaiian Volcano Observatory continues to closely monitor Kīlauea volcano, watching for any signs of accelerated rates of earthquakes or ground deformation, or signs of shallowing earthquake locations, which usually precede a new lava outbreak or propagating dike.
Scientists are also closely monitoring gas emissions and webcam imagery.
Check out Kīlauea live stream here and MITDcam, which watches the volcano’s Southwest Rift Zone.
You can also check out the most recent “Volcano Watch” article about the most recent eruption in the volcano’s Southwest Rift Zone that happened on New Year’s Eve in 1974.