Wed, 22 Mar 2023, 15:00
AVO reported that earthquake activity near Tanaga had decreased in both rate and magnitude from the peak of the swarm recorded during 9-11 March. More than 800 earthquakes, including multiple M2 and above events, were detected beneath Tanaga Island at depths less than 9 km below sea level during 11-17 March. The decline in activity decreased the potential for an eruption, so AVO lowered the Volcano Alert Level to Advisory (the second lowest level on a four-level scale) and the Aviation Color Code to Yellow (the second lowest color on a four-color scale) on 16 March.
Tanaga Island as seen from space on 23 Feb (image: Sentinel-2)
The seismic crisis near the volcano has waned significantly both in magnitude and rate from the swarm peak during 9-11 March.
Wed, 15 Mar 2023, 15:00
AVO reported that earthquake activity near Tanaga began to increase on 4 March with events up to the M2 range and located 9-18 km deep. Seismicity again increased around 1330 on 7 March and by 2045 earthquakes were occurring at a rate of 2-3 per minute. AVO raised the Aviation Color Code to Yellow (the second lowest level on a four-color scale) and the Volcano Alert Level to Advisory the second lowest level on a four-level scale).
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Fri, 10 Mar 2023, 03:57
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A distribution of earthquakes beneath Tanaga (left) and Takawangha (right) volcanoes over the past 48 hours (image: AVO)
The seismic activity continues to be elevated over the past 48 hours, a typical sign of magma pushing its way towards the surface.
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Thu, 9 Mar 2023, 09:12
At 2215 on 7 March AVO raised the Aviation Color Code for Tanaga to Yellow and the Volcano Alert Level to Advisory due to increased seismicity. Earlier that afternoon, starting at about 1330, seismicity began to increase and by around 2045 earthquakes were occurring at a rate of 2-3 per minute. The events were located at shallow depths and the largest events were M2-3.
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Wed, 8 Mar 2023, 19:36
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Tanaga volcano in November 2012 (image: Roger Clifford)
An earthquake activity beneath the volcano began to increase slowly starting at about 01:30 PM today.
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Wed, 8 Mar 2023, 15:00
At 2215 on 7 March AVO raised the Aviation Color Code for Tanaga to Yellow and the Volcano Alert Level to Advisory due to increased seismicity. Earlier that afternoon, starting at about 1330, seismicity began to increase and by around 2045 earthquakes were occurring at a rate of 2-3 per minute. The events were located at shallow depths and the largest events were M2-3.
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Thu, 2 Mar 2023, 11:00At 2215 on 7 March AVO raised the Aviation Color Code for Tanaga to Yellow and the Volcano Alert Level to Advisory due to increased seismicity. Earlier that afternoon, starting at about 1330, seismicity began to increase and by around 2045 earthquakes were occurring at a rate of 2-3 per minute. The events were located at shallow depths and the largest events were M2-3.
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Wed, 14 Apr 2021, 06:00
AVO reported that communication was reestablished with two seismic stations on Tanaga, making a total of four operational stations. On 19 April AVO changed both the Aviation Color Code and the Volcano Alert Level to Green and Normal, respectively, reflecting the resumption of seismically monitoring unrest.
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Thu, 1 Apr 2021, 06:23Low power likely due to snow cover has resulted in loss of operation and communication with all but two seismic stations at the volcano.
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Wed, 31 Mar 2021, 06:00
AVO reported a loss of operation and communication with all but two seismic stations on Tanaga, likely caused by snow cover. Both the Aviation Color Code and the Volcano Alert Level were changed to Unassigned, reflecting the inability to locate earthquakes to detect unrest. Monitoring will continue with the remaining seismic stations, regional infrasound networks, lightning detection, and satellite images.
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Sun, 27 Jan 2013, 15:51
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Current seismic recording at Tanaga volcano (TASE station, AVO)
Seismic activity is low. Some small local earthquakes including some aftershocks from the 21 Jan 5.1 quake are still occurring.
Tue, 22 Jan 2013, 08:12
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Current seismic recording at Tanaga volcano (TASE station, AVO)
A magnitude M5.1 earthquake occurred 31 km at 7 km depth southwest of Tanaga yesterday morning.
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Mon, 21 Jan 2013, 08:08
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Current seismic recording at Tanaga volcano (TASE station, AVO)
Relatively high numbers of small earthquakes continue to be recorded at the volcano.
Wed, 23 Nov 2005, 06:00
AVO reported on 25 November that for several weeks seismicity beneath young volcanic vents on Tanaga Island decreased significantly from levels recorded in early October. Satellite images of the island showed no anomalous temperatures or evidence of ash emissions. AVO reported that based on the decrease in earthquake counts and frequency of tremor episodes, the likelihood of an eruption had diminished.
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Wed, 26 Oct 2005, 06:00Elevated seismicity below young volcanic vents on Tanaga Island continued during 21-28 October. Beginning on 24 October, AVO observed weak, nearly continuous volcanic tremor in the vicinity of Takawangha volcano of the Tanaga volcano cluster. This was the first time that tremor of this sort had been observed in the volcanic cluster since the seismic network was installed in 2003.
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Wed, 19 Oct 2005, 06:00
Elevated seismic activity below young volcanic vents on Tanaga Island continued during 14-21 October, although the rate of small earthquakes reduced in comparison to peak values during early October. An unusual, several minute-long seismic signal on 17 October may have been a landslide or small phreatic explosion, but satellite images detected no airborne ash. The activity that began at Tanaga on 1 October was at the highest level recorded since the seismic network was installed in 2003, so the Concern Color Code remained at Yellow.
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Wed, 12 Oct 2005, 06:00Elevated seismic activity below young volcanic vents on Tanaga Island continued during 7-14 October, although the rate of small earthquakes reduced slightly in comparison to the previous week. The activity that began at Tanaga on 1 October was at the highest level recorded since the seismic network was installed in 2003, so the Concern Color Code remained at Yellow.
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Wed, 5 Oct 2005, 06:00
AVO detected an increase in seismic activity beneath Tanaga beginning on 1 October, with 15-68 earthquakes occurring daily. Previously, less than one earthquake had occurred per month since the seismic network was installed in 2003. The earthquakes were centered roughly 2 km NE of the volcano's summit at depths of 10-20 km below sea level.
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