A significant eruption took place at the Indonesian Merapi volcano at 06:40 UTC on January 27, 2021. The Aviation Color Code was raised to Red.
Due to the meteorological cloud, ash estimate to 12.2 km (40 000 feet) above sea level was based on the IR temperature. Ash cloud is moving NNW, the Darwin VAAC reports.
Multiple ground reports warned of a significant eruption, the center added.
In addition, volcanic ash below 7.3 km (24 000 feet) a.s.l. is expected to move NE.
The volcano produced at least 14 pyroclastic flows today, with a maximum distance of 1.5 km (0.93 miles).
This time, pyroclastic flows were observed on the southwest flanks of the volcano, reaching Krasak and Boyong rivers.
As a result, ashfall was reported in several villages in Tamansari District, Boyolali Regency, and Boyolali City.
Pengamatan awanpanas guguran Gunung #Merapi tanggal 27 Januari 2021 pukul 06.00-10.00 WIB.— BPPTKG (@BPPTKG) January 27, 2021
1. Pukul 6:03 WIB awanpanas guguran tercatat di seismogram dgn amplitudo 40 mm & durasi 83 detik, tinggi kolom tersapu angin ke arah Timur, estimasi jarak luncur 800 m ke arah barat daya pic.twitter.com/wL8DbCS8xx
7. Tanggal 27 Januari 2021 pukul 7:29 WIB, awanpanas guguran tercatat di seismogram dengan amplitudo 50 mm dan durasi 139 detik, tinggi kolom tersapu angin ke lereng arah timur, estimasi jarak luncur 1300 m ke arah barat daya: hulu Kali Krasak dan Boyong.#MerapiSiaga pic.twitter.com/df3aHyMpYu— BPPTKG (@BPPTKG) January 27, 2021
Sahabat Inisiator, BPPTKG mencatat awan panas berjarak luncur 1.200 meter meluncur ke arah sungai Krasak pada Rabu (27/1). Guguran ini terlihat hingga kawasan Kaliurang, Sleman, Yogyakarta.— #humaninitiative_diy (@hi_yogyakarta) January 27, 2021
#infojogja #infomerapi #merapi #erupsimerapi #merapierupsi #gunungmerapi #Yogya pic.twitter.com/F5qKsLmtng
BPPTKG reported that the '2021 lava dome' continued to emerge just below Merapi’s SW rim from January 8 to 14, producing a total of 128 incandescent lava avalanches that traveled as far as 900 m (3 000 feet) down the Krasak River drainage on the SW flank.
A comparison of photos taken on January 7 and 14 showed that the morphological changes in the summit area were attributed to the emergence of new lava domes.
The 2021 dome volume was an estimated 46 766 m3 (1.6 million feet3) on January 14, with a growth rate of about 8 500 m3 (300 000 feet3) per day.
Deformation continued, though at a lower rate; Electronic Distance Measurement (EDM) data showed a distance shortening between points in the NW at a rate of 6 cm (2.3 inches) per day.
On January 16, pyroclastic flows descended 1.5 km (0.9 miles) down the Krasak drainage and produced an ash plume that rose up to 500 m (1 640 feet).
The Alert Level remains at 3 (on a scale of 1-4). The public is warned to stay 5 km (3.1 miles) away from the summit.
Merapi, one of Indonesia's most active volcanoes, lies in one of the world's most densely populated areas and dominates the landscape immediately north of the major city of Yogyakarta. It is the youngest and southernmost of a volcanic chain extending NNW to the Ungaran volcano.
Growth of Old Merapi during the Pleistocene ended with major edifice collapse perhaps about 2 000 years ago, leaving a large arcuate scarp cutting the eroded older Batulawang volcano.
Subsequently, the growth of the steep-sided Young Merapi edifice, its upper part unvegetated due to frequent eruptive activity, began SW of the earlier collapse scarp.
Pyroclastic flows and lahars accompanying growth and collapse of the steep-sided active summit lava dome have devastated cultivated lands on the western-to-southern flanks and caused many fatalities during historical time. (GVP)
Featured image credit: CVGHM