A seismic swarm began on the evening of December 20 in Kilauea, accompanied by ground deformation detected by inclinometers.
Shortly after approximately 9:36 p.m. HST on December 20, the USGS Hawaiian Volcano Observatory (HVO) detected a glow in Halema'uma'u Crater at the top of Kīlauea Volcano.
An eruption has started in the summit caldera of Kīlauea. The situation is changing rapidly and the HVO will issue another statement when more information becomes available.
According to the first data, this is a small eruption limited to the caldera ... to be continued!
As a result, the HVO raised Kīlauea's volcanic alert level to WARNING and its aviation color code to RED.
On December 2, 2020, GPS stations and inclinometers recorded a ground deformation event at the summit of Kīlauea. Accompanied by earthquake swarms, the observed soil deformation patterns were consistent with a small intrusion of levee magma below the southern part of the Kīlauea caldera. The injection resulted in an uplift of about 8 cm (3 inches) of the caldera floor, and modeling suggests that it represented 0.4 to 0.7 million cubic meters (yards) of magma accumulated at about 1 , 5 km (1 mile) below the surface. Although the intrusion did not reach the surface and did not erupt, it represented a notable intrusion compared to trends seen in Kīlauea summit surveillance data streams after the 2018 eruption ended.
On December 17, 2020, seismometers detected a noticeable increase in the occurrence and duration of long-period seismic signals below the summit of Kīlauea, which is attributed to magmatic activity. While this type of seismicity was seen on average once every few weeks after the 2018 eruption, rates have increased to more than a dozen over the past few days.
Source: HVO- USGS
The explosive-effusive eruption continues in Klyuchevskoy, with this December 21 the emission of a cloud of ash at 6,000-7,000 meters asl. extending 152 km northwest of the volcano.
Despite the attenuation of the signals by the cloud cover, the thermal anomaly remains at a VRP of 988 MW on December 21 at 2:50 a.m.
The aviation code remains at orange, other explosions which may have occurred and impact air traffic.
Sources: Kvert, Mirova & VAAC Tokyo
Ruapehu's Te Wai ā-moe crater lake continues to heat and is now at 43 ° C. Warming has been accompanied by bursts of volcanic tremor and a marked increase in the amount of gas flowing through the crater lake .
The volcanic alert level has been raised to level 2 and the aviation color code has been changed to yellow.
On a gas flight last week, the lake was observed to be a uniform gray color, showing that it is well mixed. There is some flow on the outlet. The production of gas through the crater lake has also increased dramatically in response to this heating cycle. The quantities of carbon dioxide (CO2) and sulphurous gas (SO2 and H2S) in the plume are the highest measured in the last two decades. The continuous flow of gas and hydrothermal fluids through the lake shows that the underlying ventilation zone is open.
The volcanic quake is produced as short-lived pulses that coincide with an increase in gas passing through the crater lake and its plumbing system. Modeling of the energy input to the lake has shown an increase over the past month from around 200 MW to around 400 MW. Since 2007, Crater Lake's temperature has exceeded 40 ° C on several occasions without causing an eruption. However. the combination of increased lake temperature, volcanic tremor and gas production motivated the change in alert level.
Ruapehu - 12.21.2020 - The area within 2 km of Te Wai ā-moe / Crater Lake is closed to the public and concessionaires due to the increased risk of eruption. - Doc. GeoNet
During the month of November 2020 in the region of the Phlegraean Fields, 225 low-energy earthquakes were recorded with a maximum magnitude = 1.1 ± 0.3. 204 events (91%) had a magnitude less than 1.0, demonstrating a very low energy level; out of 17 events, it was not possible to determine the magnitude due to the low amplitude of the signal which is not clearly distinguishable from the background noise. A total of 124 events (55% of those recorded) were located mainly between Pozzuoli and the Solfatara-Pisciarelli region with depths not exceeding 2.5 km.
The soil deformation monitoring networks confirm a radial geometry of the ascent centered in the Pozzuoli area with an average speed of around 10 mm / month. The ascent recorded at the GPS station of Rione Terra (RITE) from January 2016 is approximately 39 cm. Thermographic measurements in the monitored areas show noticeably stable temperature trends with a slight downward trend. The geochemical parameters confirm the upward trends already observed previously.
Everything therefore seems under control and within standards.
Source: INGV - Osservatorio Vesuviano