This week at Merapi, 22 lava avalanches were observed in the southwest, dominant up to the Bebeng River with a maximum slip distance of 1,800 m.
At the southwest dome, there is no change in the height of the dome. For the middle dome, no significant morphological change was observed.
According to photo analysis, the volume of the southwest lava dome is 1,645,000 m³ and that of the central dome is 2,582,000 m³.
The intensity of the earthquakes this week is still quite high. Mount Merapi's deformation that was monitored using EDM this week showed no significant changes.
The activity level remains at 3 / siaga. The current potential danger is in the form of lava avalanches and hot clouds in the south-southwest sector covering the Boyong River for a maximum of 5 km, Bedog River, Krasak, Bebeng for a maximum of 7 km . The southeast sector covers the Woro River for a maximum of 3 km and the Gendol River for a maximum of 5 km. Meanwhile, the ejection of volcanic material in the event of an explosive eruption can reach a radius of 3 km from the summit.
Source: BPPTKG activity report from July 15 to 21, 2022
On the day of July 21, the plume from the main crater of Ibu is white and gray, with fine, medium to thick intensity, about 200-800 meters from the summit.
Seismicity is characterized by:
- 34 eruption earthquakes, with an amplitude of 15-30 mm and an earthquake duration of 20-75 seconds.
The PVMBG reports on Thursday July 21, 2022 at 6:18 p.m. WIT with the height of the ash column observed at ± 800 m above the peak (± 2125 m above sea level). It is observed that the ash column is white to gray with a thick intensity towards the west. This eruption was recorded on a seismograph with a maximum amplitude of 26 mm and a duration of 71 seconds
in addition, there was
- 5 avalanche earthquakes, with an amplitude of 2-3 mm and an earthquake duration of 15-40 seconds.
- 46 blast/emission earthquakes, with an amplitude of 5 to 14 mm and an earthquake duration of 10 to 40 seconds.
- 1 Harmonic episode with an amplitude of 3 mm and an earthquake duration of 155 seconds
- 19 shallow volcanic earthquakes, with an amplitude of 3 to 10 mm and an earthquake duration of 4 to 7 seconds.
- 1 distant tectonic earthquake
The activity level remains at 2/waspada, with an orange aviation code, with the recommendations not to travel within 2.0 km and the sector expansion is 3.5 km towards the opening of the crater in the northern part of the active crater of Mount Ibu.
Sources: PVMBG, Magma Indonesia, VAAC Darwin
The JMA informs us of the activity status of Sakurajima from July 18 to July 22 15:00.
large volcanic bombs and debris are observed scattered over 1 km of Mount Takeyama crater and Showa crater
An eruption with pyroclastic flow may occur.
At Sakurajima, the inclinometer and the extensometer installed on the island from approximately 09:00 on the 18
records slight crustal movements indicating the expansion of the mountains. From about 3 p.m. on the 20th, the change has stagnated, but the mountain body is still inflated.
At the Minamidake summit crater, a very small eruption has occasionally occurred.
In continuous GNSS observation, from about October last year (2021), in the Caldera Aira, the extension of the baseline indicating the expansion of the deep basement (in the inner part of the bay of Kagoshima) was observed.
However, the situation has been stagnating since around March.
In Sakurajima, the magma is long-lived in the deep basement of Aira Caldera (inner part of Kagoshima Bay).
The number of earthquakes and volcanic explosions is as follows: the JMA noted 3 earthquakes on 19.07, 2 earthquakes on 21.07 and 2 earthquakes on 22.07 until 3 p.m.; no explosion is mentioned.
(subject to an exact translation)