– With AAP
Experts are piecing together how a deadly tsunami could strike Indonesia without warning on Saturday night.
At least 281 people have been killed after the crashing waves hit coastal areas along western Java and southern Sumatra islands, with more than 1,000 others injured and dozens still missing.
Experts now say the Sunda Strait tsunami was caused by a major eruption from the Anak Krakatau volcano, also known as the “Child of Krakatoa”, on Friday, but are still pinpointing exactly how.
Oceanographer Dr Simon Boxall told Associated Press the tsunami was made worse by a high tide, and caused by either lava flows after the eruption or, more likely, underwater landslides as a result of the eruption.
Why was there no warning for residents?
“The problem is it occurred during a high tide, a high spring tide, which means that the water levels were already very, very high,” Dr Simon Boxall said.
“It would have only taken about 10 minutes for the tsunami to hit the coast to the west, took about an hour to hit the east.”
However, he cautioned those who are now asking “well, why aren’t there buoys there?” to consider the facts.
“It would take thousands of detector buoys, which are difficult to maintain (and are) expensive,” he explained.
“Cost isn’t the only issue. It’s also a question of networking them to actually successfully detect a tsunami.”
Dr Boxall said that because unlike many other tsunamis caused by earthquakes, there was nothing that immediately triggered fear in people that a tsunami could be coming.
“And so there wasn’t even the chance for people to realise an earthquake would lead to a tsunami [because there was no earthquake].”
He concluded that because of the speed the waves moved “there was very little that could have been done”.
“And it is just a tragic fact of nature.”