Extreme weather around the Anak Krakatoa volcano in Indonesia could trigger another devastating tsunami, experts warned, as the death toll from Saturday’s disaster rose to 429.
At least 154 others are still missing and 1,485 were injured from the tsunami, caused by an eruption of Anak Krakatoa, that hit coastal areas around the narrow Sunda Strait between the country’s two most populous islands, Java and Sumatra.
“We keep monitoring the tremor activities of Mt Anak Krakatoa, particularly under [current] extreme weather and high waves because such conditions can potentially cause the collapse of the volcano’s flank, going down to the sea, and trigger a tsunami,” Dwikorita Karnawati, chief of the Meteorological, Climatology and Geophysics Agency, told a press conference just before midnight on Tuesday.
She expressed fears that heavy rain expected to last until Wednesday afternoon could cause imminent landslides – with ruinous consequences.
“The walls of the volcano’s caldera have been getting fragile, especially if heavy rains pour onto it,” she said.
Due to the potential underwater landslides and tsunami, Dwikorita called on the public to always stay alert and “stay away from coastal areas at least between 500 metres and 1km from the shoreline.”
On Tuesday, National Disaster Mitigation Agency Spokesman Sutopo Purwo Nugroho said the search for victims and possible survivors was being expanded to outlying areas that are currently cut off by the disaster.
“The casualties may keep increasing … because there are some districts that have not been reachable due to damaged roads and collapsed bridges,” Sutopo said, adding the tsunami had displaced 16,082 people and damaged thousands of buildings, including many hotels.
Based on eyewitness testimony and preliminary analyses by experts, Sutopo said Saturday night’s tsunami was 2 to 5 metres in height, in the regencies of Pandeglang and Serang in Banten Province, on the western tip of Java.
Also affected were three regencies in Lampung Province, on the southern tip of Sumatra.
“That was why most of hotels and buildings [in Pandeglang] were flattened. If the tsunami was only between 1 and 3 metres, they would not be flattened like that,” Sutopo told the press conference, adding that many more victims might still be buried under the debris.
“We need more heavy machines to find the victims,” he said.
With some areas inaccessible to heavy machinery, rescuers have been using small tools or their bare hands to remove debris, amid torrential monsoon rains.
On Tuesday, Prayoga, who like many Indonesians goes by a single name, was seen walking at the seashore of Anyer Beach in Serang Regency, searching for bodies.
“The water level was up last night, so some victims might have been carried back ashore by the seawater this morning,” said the 21-year-old rescuer from Jakarta.
Bad weather conditions, heavy rain and high waves have hampered his search efforts since Monday night.
“We could be washed into the sea by the waves if we’re not alert and careful,” he said.
Sutopo said hotels along the beaches from Serang to Pandeglang were fully booked when the tsunami struck the areas in Sunda Strait as it is holiday season in Indonesia.
The tsunami came suddenly, with no warning, he said.
According to the Meteorological, Climatology and Geophysics Agency, the tsunami was triggered by underwater landslides caused by the partial collapse of the caldera of Anak Krakatoa, following an eruption earlier the same night.
While the country has an early warning system in place for earthquake-triggered tsunami, it does not have a similar system to warn of possible tsunami after a volcanic eruption.
“No one expected that the eruption of Mt. Anak Krakatoa would cause underwater landslides and trigger a tsunami because the eruption was not the biggest ever,” Sutopo said, adding that its eruptions in October and November were much bigger and the frequency of tremors from the volcano was not high.
“It will be a challenge for us in the future to develop an early tsunami warning system for volcanic activities because we have 127 volcanoes and 13 per cent of the world’s active volcanoes exist in Indonesia,” he said.
Although his family survived, local villager Junaedi, 32, said the disaster has left him so traumatised that he no longer wants to live near the coast and has decided to leave his village.
“It was a night with a clear sky, full moon, no rain and good weather when all of a sudden, out of the blue, the tsunami struck, without the slightest warning,” he said.