BPPTKG Reminds Potential Rain Lahar From Mount Merapi Material Hoarding

YOGYAKARTA - Geological Disaster Technology Research and Development Center (BPPTKG) reminded the public to be aware that the potential for rain lava comes from the pile of volcanic material from the eruption of Mount Merapi on the border of Central Java and the Special Region of Yogyakarta.

" potentially, the danger of lahar (rain) on Mount Merapi is still high, because the hot cloud deposits are also quite good because the eruption has been going on for the past four years," said Head of BPPTKG Agus Budi Santoso as reported by ANTARA, Monday, December 9.

He said that the volcanic material, which is estimated to reach tens of millions of cubic meters, is still buried in a number of upstream rivers leading to the eruption, especially those on the southwest side of the mountain.

"This has indeed become our concern in monitoring Merapi to be more intensive in monitoring the potential for lava events," said Agus.

Rain lava events are usually triggered by four main factors, first is the presence of hot cloud deposits from the results of the eruption that is happening and the eruption that has been going on.

Furthermore, the content of volcanic ash in Merapi materials with a level of more than 3 percent.

Even though the volume of material deposits is large, the potential is to become a small rain lava if the volcanic ash is low.

Even so, his party has not been able to confirm how much volcanic ash contains in the material deposited upstream of the Merapi river at this time.

"Next is the slope. So of course because Mount Merapi is in the form of a cone, so the buried material has the potential to become lava," said Agus.

The last factor, rainfall, although it is not yet certain how much the minimum intensity of rainfall is able to irrigate the deposits of volcanic material.

"We give the usual range from 20 to 60 millimeters per hour, yes, this happens more than an hour. To anticipate or be an early warning, usually we give notifications when it rains in the first 10 minutes then we update it," said Agus.

Based on the results of the modeling carried out by the BPPTKG, the potential for rain lava flows is estimated to reach up to tens of kilometers through rivers upstream of Merapi.

In Kali Boyong, for example, it is estimated that it can reach up to 14 kilometers, while in Kali Krasak and Copenhagen it can reach up to 20 km.

Even though it is far range, the rain lava is not expected to overflow or impact residential areas so it is still safe.

The impact of the rain lava, he said, is just a risk to sand miners in rivers upstream of Merapi.

"Well, this is how we then think about how these miners can get initial information about the potential of this lava, so they can save themselves," said Agus.