Seismologists and authorities say the tsunami was attributable to an ideal storm of things that made early detection almost inconceivable given the equipment available.
But the disaster ought to be a wake-up call to step up research on tsunami triggers and preparedness, said several experts, a few of whom traveled to the Southeast Asian country to analyze what happened.
“Indonesia has shown the rest of the world the huge variety of sources that can trigger a tsunami. More research is needed to understand these less expected events,” said Stephen Hicks, a seismologist at the University of Southampton.
Most recorded tsunamis were triggered by earthquakes. However, this time it was the eruption of the Anak Krakatoa volcano, which at high tide caused its crater to partially collapse into the sea, triggering waves up to 5 meters (16 feet) high that hit the densely populated coastal areas of the islands of Java and Sumatra.
It is estimated that about 180 million cubic meters, or about two-thirds of the less than 100-year-old volcanic island, fell into the sea during the eruption.
Dead and displaced: Indonesia counts the cost of the 2018 wave of natural disasters
Dead and displaced: Indonesia counts the cost of the 2018 wave of natural disasters
However, the eruption did not significantly shake seismic monitors, and the lack of seismic signals usually associated with tsunamis led Indonesia’s geophysics agency (BMKG) to initially tweet that a tsunami had not occurred.
Muhamad Unfortunately, the head of geophysics at BMKG, later said that tide monitors were not configured to warn of tsunamis resulting from non-seismic events.
The head of the Japan International Disaster Research Institute, Fumihiko Imamura, said he did not believe Japan’s current warning system would detect a tsunami like the one in the Sunda Strait.
“There is still some risk in Japan… as there are 111 active volcanoes and little ability to monitor tsunami-causing eruptions,” he said in Jakarta.
Scientists have long raised concerns about the collapse of Anak Krakatoa, about 155 km (100 miles) west of the capital.
A 2012 study published by the Geological Society of London deemed the site a “tsunami hazard”.
Anak Krakatoa emerged from the Krakatoa volcano, which in 1883 erupted in one of the largest explosions in history, killing more than 36,000 people in a series of tsunamis and, along with the ash, lowering global surface temperatures by one degree Celsius.
Before the tsunami that killed hundreds of people, the massive eruption of Krakatoa in 1883 shocked the world
Before the tsunami that killed hundreds of people, the massive eruption of Krakatoa in 1883 shocked the world
Some experts believe that in the 24 minutes it took for waves to reach land after the Anak Krakatoa landslide was enough time to at least partially detect last week’s tsunami.
But authorities say the nationwide tsunami warning system, consisting of buoys connected to seabed sensors, has been inoperable since 2012 due to vandalism, neglect and lack of public funds.
“The lack of an early warning system is the reason Saturday’s tsunami was not detected,” disaster agency spokesman Sutopo Nugroho said, adding that of the 1,000 tsunami sirens needed across Indonesia, only 56 were already in place.
“No signs of an approaching tsunami were detected, so people did not have time to evacuate.”
Last week, President Joko Widodo ordered BMKG to buy new early warning systems, and the agency later said it planned to install three tsunami buoys on islands surrounding Anak Krakatoa.
The cost of covering the country is estimated at 7 trillion rupees ($481 million).
This is roughly equivalent to Indonesia’s total disaster response budget of 7.19 trillion rupiah for 2018, according to Nugroho.
Other experts, however, say that even if the network worked, it would be difficult to prevent a disaster.
Another tsunami in Indonesia may be inevitable as experts fear extreme weather could collapse the Anak Krakatoa volcano
Another tsunami in Indonesia may be inevitable as experts fear extreme weather could collapse the Anak Krakatoa volcano
“The tsunami was by far the worst-case scenario for any hope of a clear tsunami warning: no clear earthquake triggering a warning, shallow water, rough seabed and proximity to nearby coasts,” seismologist Hicks said.
In the Philippines, Renato Solidum, undersecretary for disaster risk reduction, said that Taal Volcano eruptions have previously caused tsunami waves in the surrounding Taal Lake.
He said what happened in Indonesia showed the need to “re-emphasize awareness and preparedness” regarding volcanic activity and its potential to trigger a tsunami in the Philippines.
The United States also experienced several tsunamis caused by volcanic activity, including in Alaska, Hawaii and Washington, according to the national weather service.
Earlier this year in Indonesia, a double earthquake and tsunami on the island of Sulawesi killed more than 2,000 people, and at least 500 died in an earthquake that flattened much of the northern coast of the holiday island of Lombok.
In a country where, according to government data, 62.4% of the population is at risk from earthquakes and 1.6% from tsunamis, attention is now focused on a persistent lack of preparedness.
Rendang: an Indonesian delicacy that provides comfort to tsunami survivors
Rendang: an Indonesian delicacy that provides comfort to tsunami survivors
“Given the country’s disaster risk, it is time for disaster education to become part of the national curriculum,” Widodo told reporters after the most recent tsunami.
For Ramdi Tualfredi, a highschool teacher who survived last week’s waves, that improvement cannot come soon enough.
He told Reuters that residents of his village of Cigondong on the west coast of Java and near Krakatoa have never received any security drills or evacuation training.
“I was never trained in the safety steps,” he said.
“The system… has completely failed.”
This article appeared within the print edition of the South China Morning Post as: Tsunami raises questions on preparedness
