The Indonesian volcano Semeru generated 2 pyroclastic flows tonight, which spread panic among the inhabitants. According to media reports, 550 people are on the escape without evacuation orders. While trekking tours on the volcano were prohibited the day before, the alarm status remained at “yellow”. However, the affected slope in the south of the volcano is already closed.According to media reports, 550 people are on the escape without evacuation orders. While trekking tours on the volcano were prohibited the day before, the alarm status remained at “yellow”. However, the affected slope in the south-south-west of the volcano is already closed. The pyroclastic flows went down over it. The longer one covered a distance of 3 km. The two glowing clouds generated seismic signals of 18 minutes duration and with maximum amplitudes of 25 and 15 mm. They reached the base of the volcano and apparently destroyed an excavator that was inserted in one of the volcano’s drainage channels.
The VAAC detected volcanic ash at an altitude of 6100 m. The “normal” explosive activity has strongly decreased since the viscous lava flow has been extracted. It emanates from a lava dome. Probably the pyroclastic flows were created when parts of the lava flow collapsed. It is also possible that larger explosions triggered the pyroclastic flows. Harmonic tremors have been recorded, suggesting that magma is rising and erupting in the conveyor system. The dome is growing and further events must be expected.