Kelut

Kelut
	Kelut, Java
height	1731 m
location	Java ( Indonesia )
Coordinates	7 ° 56 ′ 0 ″ S , 112 ° 18 ′ 20 ″ E Coordinates: 7 ° 56 ′ 0 ″ S , 112 ° 18 ′ 20 ″ E
Type	Stratovolcano
Last eruption	02/13/2014

The Kelut , also Kelud or Gunung Kelud , is an active volcano in the east of the Indonesian island of Java . Like many other Indonesian volcanoes, it is known for violent, explosive eruptions , and is one of the most dangerous volcanoes in Java. A tunnel system was installed to drain the crater lake , which is mainly responsible for sludge flows.

The plains surrounding the Kelut are fertile and densely populated. An estimated 350,000 people live within a ten kilometer radius. The town of Kediri, with a population of around 250,000, is around 27 kilometers away . The city of Surabaya is located about 90 kilometers northeast .

history

The crater around 1919

More than 30 eruptions have been recorded since AD 1000. The duration of the inactive phases has fluctuated between nine and 75 years since the year 1300. An eruption in 1586 cost around 10,000 lives. Outbreaks occurred in the 20th century in 1901, 1919, 1951, 1966 and 1990. What they all had in common was the relatively short duration of a few hours.

On May 19, 1919, an eruption of the Kelut killed 5,110 people, as in 1586, mainly due to currents of mud, so-called lahars , which in 1919 hit areas up to 38 kilometers away within an hour. The 1951, 1966 and 1990 eruptions together killed around 250 people. Pyroclastic currents from the 1990 eruption reached areas seven to eight kilometers from the crater, and mud currents penetrated up to 15 miles into the surrounding area.

2007 eruption

On September 30, 2007, the authorities declared warning level three out of four. The reasons for this were increasing seismic activities, rising temperatures of the crater lake and changes in the chemical composition and color of the lake. Gases also rose. The population was asked to maintain a five-kilometer wide safety zone around the volcano. On October 16, 2007, the highest alert was called and the evacuation of an area of 10 kilometers around the Kelut was ordered. On November 5, 2007, the temperature of the crater lake was over 90 ° C, which led to the failure of the measuring devices in the crater lake. However, on November 9, 2007, the alert was lowered and thousands of people were able to return to their homes. In the course of November a lava dome rose above the water level in the middle of the crater lake , from which glowing masses sometimes tumbled into the lake. Volcanologists spoke of a "slow eruption".

During the course of 2008, volcanic activities came to a standstill to such an extent that in May 2008 the warning status could be reduced to the “Green” level.

Eruption 2014

The Indonesian Presidential Palace in Yogyakarta on February 14, 2014 at 7:31 a.m. in the ash rain

On February 13, 2014, another eruption began on Kelut. The ash rain that followed covered an area of about 500 square kilometers. The authorities evacuated a ten kilometer wide safety zone around the volcano. Around 200,000 people live there. In total, hundreds of thousands of people have left their place of residence. Three people died.

On February 14, 2014, the volcano hurled gas, ash and debris thousands of meters into the air. Nocturnal eruptions could still be heard in Yogyakarta, 300 km away . The area from Surabaya to Yogyakarta was covered by a thick layer of gray ash, the sky was overcast with gray, and visibility was only a few meters. The airports of Bandung , Cilacap , Malang , Semarang , Solo , Surabaya and Yogyakarta have been closed. One tried to cover the Borobudur temple with tarpaulin.

When the Kelut had not erupted again on February 15, 2014, a three-kilometer-high cloud of white smoke rose from the crater into the sky. The ash had covered the area up to 600 kilometers away. After cleaning the runways, the airports of Cilacap , Malang , Semarang and Surabaya were reopened. So far, four people have died as a result of the volcanic eruption.

The crater lake

In the crater of the volcano there was a lake fed by rainwater until 2007. He was largely responsible for the devastating lahars during eruptions. This was the reason for the planning of a drainage tunnel, which should reduce the risk of sludge flows by lowering the water level. Difficult working conditions did not lead to the implementation of a system of seven parallel tunnels with a siphon pipe for drainage until 1926 . This system is considered to be one of the world's most ambitious technical structures that have been installed to reduce volcanic hazards. After outbreaks, it has to be renewed at least in parts, but in each case it was able to keep the lake level at a low level.

An increase in the lake's water temperature was seen as an important signal of impending eruptions. The 1990 eruption was preceded by a temperature increase from 30 ° C to 39 ° C. However, in 1996 the temperature increased from 42 ° C to 50 ° C without any subsequent eruption.

Since the creation of the lava dome in 2007, only insignificant remains of the lake have remained.

The lava dome can no longer be seen on the first images of Suwarno after the eruption in February 2014.

literature

MT Zen and D. Hadikusumo: The future danger of Mt. Kelut . In: Bulletin Volcanologique . Series 2, No. 28 , 1965, p. 275-282 .
RW Van Bemmelen : The geology of Indonesia Vol. 1A, General geology of Indonesia and adjacent archipelagoes . Martinus Nijhoff, The Hague 1970, ISBN 90-247-1171-1 .
EW Brand: Landslides in Southeast Asia: a state-of-the-art report . In: IV International Symposium on Landslides (IV Symposium international sur les glissements de terrains) 1 . Canadian Geotechnical Society, Toronto 1984, OCLC 77114072 , p. 17-59 .