Mount Merapi Lava Dome Volume Increases, Level III Alert Status Maintained
The latest analysis from the Geological Disaster Technology Research and Development Agency (BPPTKG) Yogyakarta shows an increase in the volume of Mount Merapi’s lava dome. Based on drone surveys conducted on Wednesday (9/9), this volume growth is concentrated on the south-western side of Mount Merapi.
The Head of BPPTKG Yogyakarta, Agus, explained that the South-Western Dome experienced an increase of approximately 10,300 cubic metres. With this addition, the total volume of the dome in that sector has now reached 4,173,600 cubic metres.
“Meanwhile, monitoring of the Central Dome could not be performed due to obstruction by crater smoke. Its volume is considered to be the same as the previous measurement period, which was 2,369,600 cubic metres,” Agus stated in an official report on Saturday (12/9).
In addition to volume, thermal photo analysis also shows quite high temperatures on both lava domes. The temperature in the South-Western Dome was recorded at 331.7 degrees Celsius, while the highest temperature in the Central Dome was measured at 315.9 degrees Celsius.
During the observation period over the past week (4-10 September), Mount Merapi visually emitted white smoke with intensities ranging from thin to thick. This low-pressure smoke reached varying heights between 10 to 100 metres above the peak.
During the same period, 18 lava flows were recorded towards the upper reaches of the Krasak River, with a maximum travel distance of 1,800 metres. Additionally, 29 flows occurred towards the upper reaches of the Sat/Putih River, with travel distances of up to 2,000 metres.
Regarding seismicity, the BPPTKG seismic network recorded activity that remains quite intense, dominated by 620 rockfall earthquakes (RF), followed by 49 shallow volcanic earthquakes (VTB). Although the number of earthquakes is significant, the seismic intensity during this period is considered relatively stable compared to the previous week. Deformation data monitored through Electronic Distance Measurement (EDM) and GPS also showed no significant changes in the mountain’s structure.
Regarding weather conditions, no rain was reported at the observation post over the past week; therefore, there are no reports of additional flows or lahars in the rivers originating from Merapi.
BPPTKG Yogyakarta reported 117 lava flows and one pyroclastic flow (awan panas guguran) from Mount Merapi during the week. Although volcanic activity has increased, Merapi’s status remains at the Alert (Siaga) level. Based on official recommendations, the potential danger of lava flows and pyroclastic clouds still threatens several areas.