After a relative rest phase since mid-April, an explosion occurred on May 4 at the start of the day at Merapi, on Java; it was accompanied by a plume about 2,000 meters above the crater (reported by Andi Rosati on Facebook)
Merapi - 04.05.2020 - plume of the explosion at 2,000 m. above the summit - photo Andi volcanist / Facebook
Magma Indonesia reports for April 4:
- 1 avalanche earthquake, with an amplitude of 6 mm and an earthquake duration of 49.2 seconds. The sliding distance and the direction of fall are not observed.
- 4 blast earthquakes, with an amplitude of 2 to 5 mm and an earthquake duration of 15.7 to 23 seconds.
- 37 hybrid earthquakes, with an amplitude of 2-8 mm, S-P 0.3-0.4 seconds and the duration of the earthquake 5.8-11.4 seconds.
- 1 local tectonic earthquake with an amplitude of 3 mm, and an earthquake duration of 11.9 seconds.
- 1 distant tectonic earthquake with an amplitude of 5 mm, S-P 25 seconds and an earthquake duration of 71.8 seconds.
The alert level remains at 2 / waspada, with a 6 km radius prohibited around the summit.
Sources: Magma Indonesia, PVMBG, Andi volcanist and Volcano YT.
Merapi - activity table of 04.05.2020 / 00h-24h. - Doc. PVMBG
Merapi (Klangon) Timelapse (04/05/2020) - Doc. Volcano YT / Frekom
The PVMBG noted a sudden increase in seismicity on May 4, 2020 at Anak Krakatau.
This seismicity includes:
- 56 blast earthquakes with an amplitude of 11-30 mm, and an earthquake duration of 7-55 seconds.
- 236 low frequency earthquakes with an amplitude of 4 to 26 mm and an earthquake duration of 3 to 15 seconds.
- 13 hybrid earthquakes with an amplitude of 5-30 mm, S-P was not observed and the duration of the earthquake was 6 to 12 seconds.
- 2 shallow volcanic earthquakes with an amplitude of 5-6 mm, and an earthquake duration of 6-10 seconds.
- 1 internal volcanic earthquake with an amplitude of 30 mm, S-P 2.1 seconds and an earthquake duration of 8.2 seconds.
- 4 episodes of continuous tremor with an amplitude of 0.5-8 mm, dominating 2 mm.
This increase in seismicity was preceded by a moderate magnitude 5.0 earthquake with an epicenter located at the southern entrance to Sunda Strait.
To be continued ...
Sources: PVMBG, Magma Indonesia.
Anak Krakatau - summary of seismicity as of 03.05.2020 - Doc.Magma Indonesia - one click to enlarge
VAAC Darwin issued an intermittent eruption advisory to the Ibu, in the Northern Moluccas on May 4, with plume at flight altitude 70.
Magma Indonesia informs a gray-white plume between 200 and 800 meters above the crater, and at the seismicity level :
- 88 eruption earthquakes, with an amplitude of 15-30 mm, and an earthquake duration of 17-65 seconds.
- 12 avalanche earthquakes with an amplitude of 5-11 mm and an earthquake duration of 17-55 seconds. The sliding distance and the direction of fall are not observed.
- 36 blast earthquakes, with an amplitude of 5-14 mm, and an earthquake duration of 10-35 seconds.
Sources: VAAC Darwin and Magma Indonesia
IBU - eruptive plume of 04.05.2020 / 15.58 WIT - Docc.Magma Indonesia
The I.G.Peru reports that the eruptive activity of the Sabancaya volcano remains at moderate levels for the week of April 27 to May 3, 2020; that is to say with the recording of explosions, 9 per day on average, with eruptive columns up to 2.5 km high above the summit of the volcano and the consequent emission of ash and gas. Consequently, for the following days, no significant change is expected regarding its activity.
During this period, the occurrence of approximately 298 earthquakes of volcanic origin, associated with the circulation of fluids (magma, gas, etc.) inside the volcano, was recorded and analyzed.
On April 28 and May 2, two earthquakes of magnitude M3.4 and M3.5 occurred, located 12 km south of Maca and 10 northeast of Sabancaya, associated with tectonic activity.
The monitoring of the volcanic deformation of the area, using GNSS data (processed with fast orbits), does not present any significant anomalies.
A 14 MW thermal anomaly, associated with the presence of a lava body, to be identified (dome) on the surface of the crater of the volcano.
The volcanic alert level remains orange, with an inaccessible area of 12 km radius around the crater.
Source: I.G. Peru
Sabancaya - activity table from 27.04 to 03.05.2020 - Doc. I.G.Peru