At a press conference on Wednesday, BMKG’s director of earthquakes and tsunamis, Daryono, informed that the agency has not lifted the tsunami warning yet because wave oscillations can suddenly amplify in the final phase.
Five provinces have been put on tsunami alert — North Sulawesi, Gorontalo, North Maluku, Papua, and West Papua, according to the tsunami early warning issued by the BMKG following the 8.7M earthquake in Kamchatka, Russia, on Wednesday morning.
“Sometimes, non-linear oscillations in the final phase can also cause oscillations and amplification of wave heights. Oscillations in the late phase can cause significant increases,” he explained.
Although the oscillation trend is weakening, he urged the public to remain alert for sudden increases in sea waves.
The Depapre tide gauge station in Jayapura, Papua, is still recording sea level oscillations.
Based on BMKG data as of 4 p.m. Eastern Indonesian Time (WIT), the Depapre tide gauge graph showed relatively normal fluctuations, with small variations of approximately 5 centimeters.
However, after 5:00 p.m. WIT, a significant increase in oscillation amplitude was observed, rising to around 20 centimeters with rapid fluctuation.
According to Daryono, this oscillation pattern indicates an anomaly, consistent with ongoing tsunami oscillations/non-linear oscillations. This is the basis for maintaining the tsunami warning, as the potential for sudden increases is still possible.
He urged people in coastal areas to remain in safe locations and avoid the coast until official information on the lifting of the tsunami warning is released.
The BMKG, along with the National Disaster Mitigation Agency (BNPB), will continue to monitor data from tidal stations and provide regular updates to the public to ensure coordinated response measures remain in place.
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Translator: M. Riezko Bima, Resinta Sulistiyandari
Editor: Primayanti
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