JAKARTA Nov 1 Thousands of people could face risk from volcanic lahar on Indonesia's Java island as dams built to collect the material on the slopes could possibly begin to overflow, officials warned on Thursday.
The amount of lahar, a mix of mud and lava, from Mount Guntur in West Java has swelled after heavy rains and as locals continued to mine sand and stones, said Saut Simatupang, an official with Indonesia's Volcanology and Geological Hazard Mitigation in the nearby town of Bandung.
"The volcano is active but there's no increased intensity. What we are concerned (with) is a possible flow of lahar from the dams. We already issued a recommendation for evacuation two weeks ago," Simatupang said.
"However, people often don't understand what a recommendation means.
The 2,249-metre (7,378-feet) volcano in Garut district, which lies 200 km (124 miles) southeast of the capital Jakarta, is popular with tourists for its hot springs and waterfalls.
Garut police chief Eko Budi said not enough had been done to prepare for a disaster and thousands could face possible threats.
"Around 6,000 to 10,000 people are at risk if the dams cannot longer hold the flow," Budi said.
Indonesia has faced a series of deadly natural disastors in recent years and has the highest number of active volcanoes of any country. It sits on a belt of intense volcanic and seismic activity know as the "Pacific Ring of Fire".
Apart from Mount Guntur, Indonesian officials were also closely monitoring four other volcanoes for increased activity.
Mount Kelud volcano in East Java has been on the highest state of alert for several weeks as it appears to be very close to erupt, prompting the evacuation of thousands of people.
The second-highest alert has also been issued for Mount Anak Krakatau, which has been throwing up showers of ash.
The volcano, known as the "Child of Krakatau", lies in the Sunda strait between the islands of Java and Sumatra and is about 130 km west of the capital Jakarta.
It gradually formed after the famous Krakatau volcano blew up in a massive eruption in 1883, triggering tsunamis and killing thousands of people.
Simatupang said there had been increased activity on the volcano, but it was not a big danger to people.
People have been advised to stay out of a 3 km zone around the volcano, where tourists often land from small boats to scramble up its newly formed slopes.
"There have been small eruptions but they are only emitting fine ash and pebbles. The energy is very small and there can't be an eruption similar to the one in 1883," he said.
Alerts have also been issued for Mount Soputan, in North Sulawesi, which erupted last week spewing columns of ash 1,000 metres, and Mount Karangetang off Sulawesi.