Mount Merapi Shaken by 1,205 Earthquakes

During the week from Friday (7/8) to Thursday (13/8), the Yogyakarta Geological Disaster Technology Research and Development Centre (BPPTKG) recorded 1,205 earthquakes and 98 pyroclastic flows in the summit area of Mount Merapi. Head of BPPTKG Yogyakarta Agus Budi Santosa explained in a written statement on Friday (14/8) evening that the seismicity at the summit of Mount Merapi was dominated by rockfall earthquakes (RF) totalling 620 times, followed by multiphase earthquakes (MP), shallow volcanic earthquakes (VTB) totalling 49 times, 14 tectonic earthquakes (TT), and 4 pyroclastic flow earthquakes (APG). “The seismic intensity during this observation period was lower compared with the seismic intensity in the previous week,” he said. He added that this week there were 4 pyroclastic flows with a maximum runout distance of 2,000 metres towards the upper reaches of the Boyong and Sat/Putih rivers. Observable lava avalanches occurred 5 times towards the upper reaches of the Boyong River as far as 1,900 metres, 27 times towards the upper reaches of the Krasak River up to a maximum of 2,000 metres, 7 times towards the upper reaches of the Bebeng River up to a maximum of 1,800 metres, and 55 times towards the upper reaches of the Sat/Putih River up to a maximum of 2,000 metres. Meanwhile, slight morphological changes were observed in the Southwest Lava Dome due to changes in dome volume and lava avalanche activity. No morphological changes were observed in the Central Dome. Based on aerial photo analysis dated 1 August 2026, the volumes of the Southwest Dome and Central Dome were 4,039,600 cubic metres and 2,369,400 cubic metres respectively. Agus added that this week there was no rain at the Mount Merapi Observation Post and no additional flows or lahars were reported in rivers originating from Mount Merapi. Monitoring data, he said, indicates that magma supply is still ongoing, which could trigger pyroclastic flows within the potential danger zone. The volcanic activity of Mount Merapi remains quite high in the form of effusive eruption activity. “The activity status is set at Level III (Siaga),” he said. BPPTKG recorded 117 lava avalanches and one pyroclastic flow from Mount Merapi during the week. Although volcanic activity has increased, Merapi’s status remains at Siaga level. BPPTKG Yogyakarta reported volume growth in the two lava domes of Mount Merapi. The status remains Siaga with the potential for pyroclastic flows and lava avalanches. Based on official recommendations, potential hazards in the form of lava avalanches and pyroclastic flows still threaten a number of areas. Governor of the Special Region of Yogyakarta Sri Sultan Hamengku Buwono X has asked tourists not to climb to the summit of Mount Merapi. The mountain is currently at Level Three or Siaga.