Indra Harsaputra, The Jakarta Post, Kediri, East Java
As nature is hard to predict, so is Mount Kelud, East Java's charming yet baffling volcano. The Center for Volcanology and Mitigation of Geological Disasters has stated that Mt. Kelud is demonstrating a new natural phenomenon in its history.
Nov. 2, 2007 is a date the chairman of the Mt. Kelud Monitoring Team, Umar Rosadi, will not forget. At around 16:00 hours that day, countless shallow and deep volcanic tremors occurred. Over 500 quakes have been recorded since the volcano was placed on full alert status on Oct. 16, 2007.
With seismic data registering persistent vibrations, Umar and his 10-man team immediately began scurrying away from the Margomulyo monitoring station, 7 kilometers from the peak of Mt. Kelud.
"It's going to blow!" shouted a team member to guards posted at the gate of Kelud park.
The guards were aghast at the sight of the monitoring team speeding away in their car. Instinctively, they darted away, along with local police personnel. Dozens of Sugihwaras villagers followed in panic, abandoning their homes. That day, the tranquil village resembled a motor rally.
Several hours passed, but Kelud's summit remained relatively calm. The monitoring team finally returned to their station while some local communities chose to stay in refugee camps for fear of an eventual eruption.
So far, however, Mt. Kelud has not done so. On Nov. 29, the volcano's alert status was lowered again.
"No other volcano in Indonesia has ever `survived' such (a series of) quakes. Mt. Kelud should have exploded," Umar told The Jakarta Post.
Hazardous tourist spot
In spite of its dangers, the 1,724-meter mountain on the border of the Kediri and Blitar regencies, or around 150 kilometers from the provincial capital of Surabaya, is an enchanting destination for tourists.
As one of hundreds of volcanoes in the country, Mt. Kelud has erupted 30 times since 1311, the latest taking place in 1990. In the disasters inflicted by Kelud, the cumulative death toll has reached over 15,000.
The 1990 eruption created a green lake in the crater of the volcano, offering a superb panorama. It is thus unsurprising that Mt. Kelud has become a major tourist attraction since then, generating considerable revenue for the regency coffers.
While the two regencies once disputed their jurisdiction over this are, Kediri has finally gained rightful administrative control.
A ritual offering is held annually in the Kelud area. Resembling the local people's traditional ceremonies, the ritual is, in fact, more aimed at drawing the attention of domestic and foreign tourists. Today, the rite is conducted by the caretaker of the tourist area, Mbah Ronggo. Mbah Ronggo moved to he slope to be an ascetic, and has lived there these past 15 years.
Ronggo is locally known as a witch doctor and exorcist, but those living on and around the mountain do not readily follow his advice about the volcano's imminent danger, as they prefer to consult their own village elders. Mbah Agung is one such elder.
The elder of Kalibladak village in Nglegok district, Agung has earned the villagers' trust in his views on Mt. Kelud. When the Post last saw him, Agung claimed to have received a supernatural message that the volcano would erupt at 2 o'clock -- either in the wee hours, which would result in many victims, or in the afternoon with none -- but he did not specify a date.
Several other paranormal forecasts put the time of eruption at the end of December 2007 or before New Year's, in mid-2008, or after the East Java gubernatorial election slated for June 2008.
Some "psychics" believed that the disaster would be preceded by an affliction or bloodshed -- but these are mere predictions.
"The fact is that Mt. Kelud has remained steady so far. Earlier, I thought it would erupt soon, but it seems the mountain is too shy to accept my proposal," joked Surono, head of the Center for Volcanology and Mitigation of Geological Disasters.
Lava dome: New phenomenon?
Surono said the volcano was now in the phase of developing a lava dome, which was formed by magmatic pressure pushing up from beneath the lava cap left behind by the 1990 eruption.
"The lava dome will likely keep growing and change the layers of the mountain's crater lake into a sharp arc. We're monitoring the growth daily," he added. The dome has continued to expand at 8 square meters per second, and now measures 130 meters in diameter, with an area of 700,000 sq m.
According to Surono, the lava dome is a new phenomenon for Mt. Kelud. In the 1990 eruption, the volcano indeed developed a lava cap, but this cap did not turn into a swelling lava dome.
On the other hand, Amien Widodo, a geologist and head of the Center for Disaster Studies at the 10 November Institute of Technology-Surabaya, said the lava dome emerging from the Kelud crater was not new. Based on documents from the Netherlands, such a dome had emerged prior to the eruption in 1919.
"We don't have records of Mt. Kelud's developments in the period before 1966. Most of the data on this volcano are kept in the Netherlands. In point of fact, natural phenomena have to be studied by examining complete records," said Amien.
"The (Dutch) documents reveal that the lava dome, composed of andesite, was blown apart and discharged as rock and gravel in a past eruption, followed by showers of sand," he continued. The dome, crushed by magmatic forces, deepened the crater lake, but further specifics are not found in the data.
At present, the lake is 38 m deep with a water volume of 2.5 million cubic meters. Once, the lake was reportedly more than 600 m deep with a capacity of 40 million cu m.
"The 1919 eruption claimed the largest number of human lives, reaching 5,160," added Amien.
He noted that the Kelud's new dome and recent emissions with accompanying tremors and smoke pillar -- up to 120 m high -- should be taken with extreme caution, as they could be signs of a devastating explosion like that in 1919.
"In theory, this volcano is on the verge of erupting. The higher and more massive the dome, the greater its blast impact," Amien warned.
According to him, it is presently difficult to estimate the Volcano Explosive Index (VEI) of Mt. Kelud, which has ranged historically from 3 to 5. It recorded VEI 5 in 1856, which is equivalent to the 1991 eruption of Mt. Pinatubo in the Philippines that killed 932, and the 1980 eruption of Mount St. Helens in the United States.
In comparison, the infamous eruption of Mt. Krakatau on Aug. 27, 1883, recorded VEI 6 with a death toll of 36,000.
"But it's still hard to predict when Mt. Kelud will blow up, even with the available scientific documents," Amien said.
No comments:
Post a Comment