ANGERED Indonesian netizens have taken the country’s geophysics agency to task for purportedly lifting a tsunami warning about half an hour before huge waves struck the Sulawesi island late on Friday, leaving more than one thousand dead or missing.
The tsunami, which came after a 7.5-magnitude earthquake, hit the city of Palu, some 1,500 kilometres from the capital Jakarta, sweeping away hundreds of people who gathered for a festival on the northeastern city’s beach.
The Indonesian Agency for Meteorology, Climatology and Geophysics (BMKG) admitted shortcomings in its ability to provide warnings of impending tidal waves, but the timing of its alert on Friday became a subject of heated debate over the weekend.
— #KataNalar (@ZAEffendy) September 28, 2018
According to The Guardian, the agency said it followed standard operating procedure and made the call to “end” the warning based on data provided from the closest tidal sensors, some 200 kilometres outside Palu.
“We have no observation data at Palu. So we had to use the data we had and make a call based on that,” head of the earthquakes and tsunami centre at BMKG, Rahmat Triyono, was quoted as saying.
— #PrayForPaluDonggala (@IpungLombok) September 28, 2018
The only waves detected by the tide gauge, he said, was that of an “insignificant” 6cm wave that did not involve the giant waves that struck Palu.
“If we had a tide gauge or proper data in Palu, of course it would have been better. This is something we must evaluate for the future,” Triyono said.
The agency had issued a tsunami warning but whether or not it was lifted before the high-velocity waves came crashing into the city at hundreds of kilometres per hour, was not clear.
This is where we living
And we are under 1/10 scale compare to Japan in preparedness!!
— [PrisonRepublic] (@ndyArthrunZarra) September 30, 2018
“Based on the videos circulating on social media, we estimate the tsunami happened before the warning officially ended,” Triyono said.
An expert expressed surprise that the quake had generated a tsunami.
@infoBMKG statement: #Palu #Earthquake #Tsunami occured at 1027UTC, Tsunami warning was revoked at 1036UTC. Tidal gauge at Mamuju detected an earlier tsunami passing it at 1013UTC. So, BMKG did NOT revoke the Tsunami warning before the tsunami. Let's make that clear.
— Gerry Soejatman (@GerryS) September 28, 2018
Baptiste Gombert, a geophysics researcher at the University of Oxford, said Friday’s quake was a “strike-slip event” where tectonic plates move horizontally against each other, rather than vertically, which is what usually generates a tsunami, according to the Guardian.
“There is some speculation that there was a landslide under the sea, which displaced a lot of water and caused the tsunami,” he said, adding the Palu’s narrow bay may have concentrated the force of the waves as they moved toward the shore.
Indonesia’s spokesman for the disaster agency Sutopo Purwo Nugroho, said authorities were preparing warnings that “were easy to understand” but the tsunami warning has ended.
He said the power and communications lines that were brought down from the quake had prevented residents from receiving alerts via text messages by the communications ministry.
Other experts said Indonesia’s tsunami warning system had been “stuck in testing” for years.
According to the Sydney Morning Herald, the Indonesian government had stalled the replacement of a high-tech system of seafloor sensors, data-laden sound waves and fibre-optic cable that was meant to replace an earlier system set up in wake of the earthquake and tsunami that killed 250,000 in the region in 2014.
The prototype of the new system which would have cost only US$95,000 to become fully operational remained unchanged owing to inter-agency wrangling and delays. The US National Science Foundation had developed the new system with a US$4.1 million fund.
“To me this is a tragedy for science, even more so a tragedy for the Indonesian people as the residents of Sulawesi are discovering right now,” said Louise Comfort, a University of Pittsburgh expert in disaster management who has led the US side of the project.
“It’s a heartbreak to watch when there is a well-designed sensor network that could provide critical information.”