Mount Merapi Experiences Hot Clouds Falling Three Times in a Week, Volcanic Activity Increases and Status Remains on Alert

KabarJawa.com– Mount Merapi’s activity is again showing high intensity. Throughout the period 23–29 January 2026, the peak of the most active volcano in Indonesia experienced three incidents of hot cloud avalanches (APG).

This phenomenon confirms that the magma supply is still ongoing and has the potential to trigger further dangers in disaster-prone areas.

Head of the Geological Disaster Technology Research and Development Center (BPPTKG), Agus Budi Santoso, said that the results of visual and instrumental monitoring showed that the effusive eruption activity of Mount Merapi was still continuing.

Therefore, BPPTKG set the activity status of Mount Merapi at Level III or Alert.

Hot Clouds Fall in a Week

During the week of observations, the weather around Mount Merapi was generally clear in the morning and evening. However, fog often covers the peak area from noon to evening.

Under these conditions, observers noted that Mount Merapi consistently emitted white smoke with light to thick intensity.

The volcanic smoke has weak pressure with a height varying between 10 and 25 meters from the top of the crater. This activity shows that the magma degassing process is still taking place actively within the body of the mountain.

BPPTKG recorded three incidents of hot cloud avalanches during the week. The hot cloud rolled a maximum distance of 1,500 meters towards the upstream of the Bebeng River, an area that is included in the potential danger zone.

Apart from hot cloud avalanches, lava avalanche activity also occurs with high intensity.

• 2 lava avalanches upstream of Kali Boyong with a maximum sliding distance of 1,700 meters
• 53 lava flows upstream of Kali Krasak as far as a maximum of 2,000 meters
• 36 inhabitants
• 60 lava avalanches upstream of Kali Sat/Putih with a maximum distance of 2,000 meters

This series of avalanches shows that the lava material continues to experience instability around the peak and lava dome.

The results of morphological analysis using the Deles 5 and Babadan 2 monitoring cameras show changes in the shape of the Southwest Lava Dome. These changes occurred due to the dynamics of the dome volume and the high intensity of lava avalanche activity.

In contrast, the Middle Dome does not show significant morphological changes. Based on analysis of aerial photos dated December 13 2025, BPPTKG recorded the volume of the Southwest Dome at 4,171,800 cubic meters, while the Middle Dome was recorded at 2,368,800 cubic meters.

Seismic Activity Increases Significantly

Mount Merapi’s seismic network recorded an increase in earthquake intensity during this observation period compared to the previous week. BPPTKG recorded the total earthquake events as follows.

• 3 Hot Cloud Fall (APG) earthquakes
• 10 Shallow Volcanic earthquakes (VTB)
• 602 Multiple Phase (MP) earthquake
• 1 Low Frequency (LF) earthquake
• 787 Earthquake Fallout (RF)
• 42 Tectonic earthquakes (TT)

This seismic pattern indicates that the movement of magma and volcanic material is still active beneath the surface of Mount Merapi.

Deformation measurements using Electronic Distance Measurement (EDM) and Global Positioning System (GPS) show relatively stable conditions. The EDM plunge distance in the northwest sector from point BAB0 to reflector RB2 was measured in the range of 3,840.336–3,840.344 meters.

Meanwhile, the Labuhan–Jrakah GPS baseline data was measured in the range of 7,108.13–7,108.15 meters. BPPTKG concluded that the deformation of Mount Merapi has not shown significant changes during the reporting period.

During the observation week, rain poured down several monitoring posts around Mount Merapi. The highest rainfall intensity was recorded on January 26 2026 at Kaliurang Post, with rainfall of 38.13 mm per hour for 109 minutes.

However, BPPTKG has not received reports of lava flows or an increase in river discharge that originates at Mount Merapi.

BPPTKG emphasized that the main potential danger currently is lava avalanches and hot clouds in the south to southwest sectors.

• Boyong River as far as a maximum of 5 km
• The Bedog, Krasak and Bebeng rivers are a maximum distance of 7 km
• Woro River as far as a maximum of 3 km
• Gendol River as far as a maximum of 5 km

Apart from that, ejections of volcanic material have the potential to reach a radius of 3 km from the peak if an explosive eruption occurs.

Regional governments in Sleman, Magelang, Boyolali and Klaten Regencies need to continue to improve disaster mitigation efforts, strengthen community capacity, and prepare evacuation facilities and infrastructure.

Then, people should not carry out any activities in potential danger zones, be aware of the threat of hot clouds of avalanches and lava, and anticipate disturbances caused by volcanic ash.

BPPTKG emphasized that it will review the status of Mount Merapi if there are significant changes in activity.

The public should only access official information through the nearest Mount Merapi Observation Post, the official BPPTKG and MAGMA ESDM websites, the Magma Indonesia application, BPPTKG social media, VHF 172,000 MHz radio, or directly to the BPPTKG office on Jalan Cendana No. 15, Yogyakarta. (ef linangkung)