Indonesia Tsunami Death Toll Crosses 280: What Caused The Killer Waves?

The death toll from the Indonesian tsunami that struck coastal areas around the Sunda Strait on Saturday night has risen to 281. Authorities warned the toll could rise further as several affected areas were not reached by the rescue teams.

The tsunami, prompted by the eruption of the Anak Krakatoa volcano, left over 1,000 people injured and 11,600 people displaced. Indonesia’s disaster management agency said over 600 houses, 60 shops and 420 vessels were damaged.

“Evacuation, search and rescue of victims continues. Allegedly there are still victims who are under the rubble of buildings and material washed away by the tsunami,” Sutopo Purwo Nugroho, head spokesman of Indonesian National Board for Disaster Management, said.

Based on satellite images, scientists said the tsunami was caused by collapse of a portion of the volcano. "Underwater landside is the leading theory. So when that land pushes into the ocean ... it displaces the ocean surface causing the vertical displacement that causes the tsunami," said Sam Taylor-Offord, a seismologist at GNS Science in Wellington, Reuters reported.

The Indonesian Red Cross released a video from an affected area, warning residents to stay away from the coast as the water levels were still high.

Indonesian President Joko Widodo was also at the scene. “We request prayers from all over the country so that we are all given salvation, patience and strength,” he tweeted.

A video showing water washing away an outdoor stage where Seventeen, a local band, was performing went viral. All the members of the band except the singer died.

“Bani will be buried at 1:00 p.m. in Gamping. Herman will be buried today at Tidore. Oki will be buried at 16.00 in Krapyak. Ujang was buried this afternoon in Ciledug,” the singer wrote on Instagram.

Indonesia sits on the seismically active Ring of Fire, an arc of volcanoes in the Pacific Ocean basin, because of which it is frequently hit by earthquakes and tsunamis. Several scientists shared their analysis on why the tsunami came without a warning.

“Tsunamis can be caused by volcanically induced landslides above or below water, and by volcanic eruptions themselves. Unlike tsunamis caused by earthquakes, such volcanically induced tsunamis may not trigger warning systems that are designed to alarm after large quakes, and thus may provide little warning, unless observed directly or detected by other devices such as wave buoy warning systems. Particularly when the volcano in question, as with Anak Krakatau, is already active and displaying activity such that its eruption is not a new or a surprise event,” Dougal Jerram, a professor at the University of Oslo told the Guardian.

Simon Boxall from the National Oceanography Centre said, “ There will be an outcry as to why an early warning system didn’t kick in. The same criticism was levelled after the September Palu tsunami which killed 2,000 people. These tsunamis are very localized and to cover the Indian Ocean with sufficient sensors to warn against all such eventualities would require many thousand buoys on the network. In shallow water the energy of the tsunami is quickly dispersed and so in this case the wave didn’t travel as far from source as the very destructive 2004 Boxing Day tsunami which occurred in the deep ocean.”