TEMPO.CO, Bandung - Meteorology, Climatology and Geophysics Agency (BMKG) claimed that they were completely `blind` about the tsunami after the strong earthquake that hit Donggala, Palu, Sigi and the surrounding areas on Friday, September 28.
"The problem is that there was no sea level monitoring data, so we were completely `blind` about the condition in Palu City," said BMKG Head of Earthquake and Tsunami Early Warning Information, Daryono, Sunday, September 30.
The earthquake measuring 7.4 on the Richter scale occurred at 5:02 p.m. "About six minutes after the earthquake, the early warning of the potential for a tsunami was issued," said Daryono.
However, BMKG officers could not contact the officers in the Palu area. "We couldn't call, we couldn't do anything," he said. When the tsunami hit Palu Bay, it was occurred around 5:22 p.m.
Daryono said his party was looking for a tsunami confirmation to Mamuju, and there was a six-centimeter sea level rise at 5:27 p.m.
BMKG said that the tsunami was relatively small and it ended the early warning at 5:36 p.m. "Not revoked, if we revoke it, we are wrong," he said.
Some geologists say the tsunami occurred because of the possibility of the steep and deep condition of the Palu Bay. "Our tsunami early warning does not involve avalanche, because it is a pure tectonic earthquake," said Daryono.
Daryono said that the early warning device system in Indonesia was not perfect. "If you look at the fracture movement that is horizontal or shifted, there will be no tsunami, but if there is one, it would be very small," he said.