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Earth of fire

Actualité volcanique, Articles de fond sur étude de volcan, tectonique, récits et photos de voyage

Publié le par Bernard Duyck
Publié dans : #volcanic activity

At Anak Krakatau, level II (Waspada); the seismicity of March 18, is characterized by:

- 2 eruption earthquakes, with an amplitude of 20 to 42 mm and an earthquake duration of 44 to 608 seconds.

- 5 blast earthquakes, with an amplitude of 3-6 mm, and an earthquake duration of 12-15 seconds.

- 2 episodes of harmonic tremor with an amplitude of 3-5 mm and an earthquake duration of 1080-21600 seconds.

- 1 low-frequency earthquake with an amplitude of 6 mm and an earthquake duration of 7 seconds.

- 2 volcanic earthquakes with an amplitude of 12-22 mm, S-P 2-2.5 seconds and the duration of the earthquake 8-16 seconds.

- 3 episodes of continuous tremor with an amplitude of 0.2-25 mm, mainly 2 mm.

 

Sources: Magma Indonesia and Volcano YT / PVMBG

Anak Krakatau - seismogram of 18.03.2020 / 8 p.m. - 19.03.2020 - Doc. Magma Indonesia

Anak Krakatau - seismogram of 18.03.2020 / 8 p.m. - 19.03.2020 - Doc. Magma Indonesia

This Krakatau (Crater) Timelapse (18/03/2020) video was created by https://volcanoyt.com/camera/119 Source: PVMBG

After four weeks at alert level 2, the activity of Taal in the Philippines shows low-intensity volcanic seismic activity, stabilization of the deformation of the caldera and Volcano Island soil, and low surface activity in the main crater. and the crack of Daang Kastila.

Taal by Landsat / Nasa EO on December 6, 2019 (before the eruption) and two months after the eruption. According to NASA's Earth Observatory, the fall of ash resulting from the Taal volcano eruption on January 12 was particularly problematic because it got wet enough to have a sort of muddy texture and then it dried and hardened into a material that looks like cement - see damage to aquaculture areas (left) and cultivation / farming areas (right) - one click to enlargeTaal by Landsat / Nasa EO on December 6, 2019 (before the eruption) and two months after the eruption. According to NASA's Earth Observatory, the fall of ash resulting from the Taal volcano eruption on January 12 was particularly problematic because it got wet enough to have a sort of muddy texture and then it dried and hardened into a material that looks like cement - see damage to aquaculture areas (left) and cultivation / farming areas (right) - one click to enlarge

Taal by Landsat / Nasa EO on December 6, 2019 (before the eruption) and two months after the eruption. According to NASA's Earth Observatory, the fall of ash resulting from the Taal volcano eruption on January 12 was particularly problematic because it got wet enough to have a sort of muddy texture and then it dried and hardened into a material that looks like cement - see damage to aquaculture areas (left) and cultivation / farming areas (right) - one click to enlarge

- The volcanic earthquakes went from 141 events / day between January 26 and February 14 to 31 events / day between February 14 and today. The majority of these earthquakes were associated with rock fracturing processes and only six (6) low frequency events associated with magmatic or hydrothermal activity were detected until March 6. These parameters are consistent with the degassing of the magma in the basin rather than with the active transport of the magma to and from the shallow magma reservoir under Volcano island.

- At the deformation level, a very slow and slight uplift of the northern sector of the Taal caldera but a continuous subsidence of the southern sector of the caldera and the south of Volcano island are recorded, generally consistent with the post-eruptive relaxation of the Taal.

- The flow of sulfur dioxide has passed below the detection level, a situation compatible with a shallow source of magma with low degassing and absorption or "washing" of volcanic gas by a lake being recovered in the main crater and by the volcano island hydrothermal recovery system.

- Surface activity decreased with a low emission of plumes loaded with steam from 50 to 100 meters high from fumaroles or active gas conduits on the main crater and along the crack of Daang Kastila on the northern flank from Volcano island.

 

In view of the above, DOST-PHIVOLCS lowers the alert status of the Taal volcano from alert level 2 to alert level 1; alert level 1 means that the volcano is still in an abnormal state and should not be interpreted as the disturbances have ceased or the threat of an eruption has disappeared. 

DOST-PHIVOLCS reminds the public that at alert level 1, sudden steam or phreatic explosions, volcanic earthquakes, minor ash falls and deadly accumulations or expulsions of volcanic gas can occur and threaten areas within TVI. DOST-PHIVOLCS strongly recommends that entry into Volcano Island, the Taal Permanent Danger Zone or PDZ, especially around the main crater and the Daang Kastila fissure, be strictly prohibited.

 

Sources: Phivolcs & Nasa

 Reykjanes peninsula - location and magnitude of earthquakes on 18.03.2020 / 12.50pm - Doc. IMO
 Reykjanes peninsula - location and magnitude of earthquakes on 18.03.2020 / 12.50pm - Doc. IMO

Reykjanes peninsula - location and magnitude of earthquakes on 18.03.2020 / 12.50pm - Doc. IMO

At 10:32 a.m. on March 18, an M4.2 earthquake was detected approximately 3 km northwest of Gunnuhver on the Reykjanes Peninsula.

IMO has received numerous sentiment reports from Reykjanes and IMO headquarters. Few aftershocks followed.

The latest distortion results around Mount Thorbjorn on the Reykjanes Peninsula indicate that inflation causing an uprising in the region has resumed. The uprising is slower than when it was measured in January, but seems to be in the same place. The most likely explanation for the signal is that the influx of magma has started again.

 

Source: IMO / Written by a specialist on March 18 10:48 GMT

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