Mount Merapi’s alert status lowered

Mount Merapi’s alert status lowered
Sri Wahyuni and Slamet Susanto, The Jakarta Post, Yogyakarta | Sat, 12/04/2010 1:06 PM

Mount Merapi’s alert status was lowered as of Friday evening, but people living on the slopes of the volcano were told to remain cautious of possible secondary eruptions.

Residents were also reminded about the danger of floods of mud whenever there were heavy rains at the volcano’s peak.

Volcanology and Geological Disaster Mitigation Center head Surono said intense rain at the peak of Indonesia’s most active volcano could incite both secondary eruptions and mud floods along the 12 rivers that originated at Merapi.

“Merapi’s 2010 eruptions have spewed an enormous amount of volcanic material, 150 million cubic meters of pyroclastic deposits and other materials,” Surono said on Friday.

Surono said thick and hot pyroclastic deposits could explode when they came into contact with heavy rain. This is as dangerous as the pyroclastic flows themselves because it can cause volcanic ash, sand and even big rocks to rush down rivers, he said.

He called on people to stay away from all rivers that originated from Merapi, as they were all completely filled with sediment from Merapi’s volcanic material.

“Areas at least 300 meters from the banks of these rivers must be cleared from any human activities,” he said.

Surono also said that with the alert status decrease, the danger zone had been reduced to a radius of 2.5 kilometers from the crater, except for the three districts of Cangkringan, Ngemplak and Pakem in Sleman regency on the southern slopes of Merapi, which remain within a 15-kilometer radius.

“These are the districts where the pyroclastic flows have been frequently heading,” Surono said.

He said this was also due to morphological changes at the volcano’s peak. The crater is opening up to the south, thus the threat of possible pyroclastic flows increased in that direction, he said.

The alert status decrease was based on both visual and instrumental observations as of Thursday, which had continued to show decreasing, stabilizing volcanic activity, he said.

In a related development, floods of mud covered thousands of houses along the banks of the Code River, which passes through the city of Yogyakarta, on Friday afternoon, following heavy rains at Merapi’s peak that same day.

The rain had caused sediment from the volcano to flow down the Merapi-originating Boyong River into the Code River.

“The floods started at around 2:30 p.m. In just a half an hour a flash flood came and destroyed people’s homes,” local resident Wasono of Ledok Tukangan, Danurejan, Yogyakarta, said.

The beating sounds of kenthongan bamboo drums were heard repeatedly throughout the afternoon, warning people of the threat of flooding and giving signals to evacuate.

Women, children and the elderly were evacuated to safer places, while men stayed on guard along the river’s banks, mending damaged piles of sandbags to prevent the water from entering their houses

“We had not even finished clearing the sandbags from our neighborhood from Monday’s flood. Now flooding comes again,” another resident, Jumadi, said.