The story of the animals that ran down toward the volcanic eruption is often a natural marker for local people to evacuate.Research Head of Volcanology and Disaster Mitigation in Kelud Surono scientifically explain about the animals that come down the mountain before the eruption.
Giyono (71) for most of her life in charge of monitoring the activity of Mount Kelud. He served in the post in the village monitoring Kelud Sugihwaras, Kediri, East Java. It has been four times he witnessed the eruption of Kelud, namely 1956, 1966, 1990, and 2007. According to his testimony, before Kelud erupted, the animals ran down the mountain. "Usually, snakes and deer down before Kelud erupts," he said.
Geologists Geological Museum, Indyo Pratomo, also witnessed the animal down before the eruption of Mount Kelud on February 10, 1990. On December 1989, Indyo who was researching for his dissertation at the University of interests Blaise Pascal, Clermont-Ferrand II, France, witnessed the python that comes out of the nest and arrested people on the slopes of Kelud.
In fact, in late December, the Indyo and his partner, vulcanologist from the University of Savoie, France, Jean Van de Meulbreuck, and Khairul Huda, postal officials monitoring Kelud, stung by hundreds of wasps bangbara (Xylocopa spp)-wasps NDAs, in the Java language - the rage for no reason. At that time, they were in the tunnel, not far from the crater of Kelud. "Wasps is such confusion and anger to anyone who is nearby without cause," he said. Indyo and two colleagues to be admitted to hospital with hundreds of wasp's sting.
On the other mountains, a similar story also mentioned the witnesses. So far, the story of the fall of the animals from the volcano before the eruption is often used as a sign of local communities to contribute to evacuate. Animals are considered to have a "sixth sense" that can detect something that humans can not be touched.
High-frequency
For Head of Volcanology and Geological Hazard Mitigation Surono, this phenomenon could be explained scientifically.Towards Kelud eruption in 1990, Surono acoustic monitoring equipment installed on the mountain for the sake of his dissertation at the University of Grenoble, France. He put up a tool to monitor low-frequency sound waves (0.1 to 50 Hertz / Hz), intermediate frequency (200 Hz-5000 Hz) and high frequency (above 15 kHz).
"I posted three frequency detector to determine the mechanisms that occur in the body when its activity increased Kelud," he said.Towards Kelud erupted in 1990, the mountain is very calm and quiet of the earthquake so that the required indicators, namely the sound.
"Before the volcano erupted, there is the fluid pressure (can be a gas, vapor, or magma) that drives the stopper of the mountain," he said. However, this pressure can still hold the stopper of the mountain. The rocks also have a certain elasticity of power. When pressed, he will flex before the point will be broken.Encouragement of high pressure that hit the mountain is what is causing the plug high-frequency noise heard only the sound of certain animals. "It was then that animals can not stand the noise of it running down from the mountain," said Surono.
With high-frequency sound can be heard is not the only man able to hear sounds with a frequency of 20 Hz-20 kHz. In contrast to animals, such as bats or bees, which can capture sounds with frequencies up to above 100 kHz. When later, the rock is perforated stopper, then an eruption will occur. So, when the animals began to come down the mountain, can be regarded as a marker of the mountain will erupt.
From his research, Surono find, high-frequency noise starts to increase at December 16, 1989, then jumped high and reached its maximum on December 28, 1989, then constant since January 10, 1990. By matching data from Indyo Pratomo stung by wasps in late December, Surono conclusion, the strange behavior of animals was due to increases in high frequency in the mountain.
On January 16, 1990, the high frequency is then decreased rapidly, which indicates the stopper is broken and finally Kelud erupted on February 10, 1990. At the high-frequency sound down, the rocks have been cracked. Earthquake volcanic rocks appears as already experienced fractures, coupled with increasing low-frequency acoustic pressure.
Acoustic indicator
According to Surono, acoustic or sound detectors could be an alternative tool in monitoring volcanoes with crater lakes, particularly the activity Kelud kegempaannya less. "In the water, just a wave of press that can run. Shear waves and the other can not be spread on the water. That's why acoustic important indicator mounted on a volcano that has a crater lake, "he said.
However, according to Surono, not all of the mountain which has a crater lake can be installed this tool. "Crater Lake that there can not be fitted with a fish because it will disturb the fish," he said. In Indonesia, according to Surono, in addition to success at the time Kelud erupted in 1990, this acoustic instrument has not been applied in other mountains. "When Kelud crisis in 2007, the tool I was actually broken," he said.
For a while, the animal can still be used as one indicator of increased volcanic activity is most easily viewed by the public.
"The problem is, many animals that have been hunted Kelud," said Giyono.
Therefore, according to Surono, not to be fooled and do not want people displaced by the eruption of Kelud ahead, no more animals down the mountain. Moreover, an indicator of the decline of these animals is also just one of many ways to detect an increase in volcanic activity, such as the increase in volcanic earthquakes, volcanic body changes, and increased water temperature of the crater.
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