PVBMG Evaluation Of Mount Semeru With Alert Status

Photo: Doc. Antara

JAKARTA - The Center for Volcanology and Geological Hazard Mitigation (PVMBG) evaluates the activities of Mount Semeru with Alert or Level II status at the border of Lumajang and Malang Regencies, East Java.

"The results of the evaluation noted that the activity of Mount Semeru for the period 16-31 July 2024 showed that the eruption, hot clouds, and lava avalanches were still happening, but visually rarely being observed due to fog weather," said Head of PVMBG Priatin Hadi Wijaya in a written statement, quoted from Antara, Saturday, August 3.

According to him, the accumulation of eruptive materials and the formation of Scoria cones has the potential to become incandescent lava avalanches or hot clouds.

"The lava avalanche material and or hot clouds that have been deposited along the river flow that originates at the top of Mount Semeru have the potential to become lava, when interacting with rainwater," he said.

In addition, he continued, the interaction of lava avalanche material deposits or hot clouds with high temperature with river water will have the potential for secondary eruptions.

He said that during that period the number of earthquakes recorded showed that the seismic activity of Mount Semeru was still relatively high, especially earthquake eruptions, avalanches, harmonics, and deep volcanic.

"The recorded deep volcanic earthquake and harmonic tremor indicated supply from below the Semeru surface along with the release of material to the surface, as well as the process of buildup of eruptive materials around the Jonggring Seloko crater," he said.

The recorded occurrence of flood vibrations during that period indicated that there was an incident of lahars in the river that originated at Mount Semeru, especially those leading to the Besuk Kobokan flow.

"Based on the results of thorough analysis and evaluation, the level of activity of Mount Semeru remains at Level II or Alert with recommendations that are adjusted to the latest potential hazards," he said.

With Alert status, the public is prohibited from carrying out any activities in the southeast sector along Besuk Kobokan, as far as eight km from the summit (the center of the eruption).

Then outside of that distance, he continued, people are not allowed to carry out activities at a distance of 500 meters from the riverbank (river border) along Besuk Kobokan, because it has the potential to be affected by the expansion of hot clouds and lava flows up to a distance of 13 km from the summit.

The community is also not allowed to move within a three km radius of the crater/peak of Mount Semeru because it is prone to the danger of throwing stones (pijar).

In addition, he said, it is necessary to be aware of the potential for hot clouds, lava avalanches, and lahars along rivers/valleys that originate at the peak of Mount Semeru, especially along Besuk Kobokan, Besuk Bang, Besuk Kembar, and Besuk Sat, as well as the potential for lava in small rivers that are tributaries of Besuk Kobokan.