KONTAN.CO.ID - JAKARTA. Central authorities have warned residents to temporarily halt activities along the beaches of the Sunda Strait, following what they called a volcanic earthquake on Anak Krakatau volcano that had triggered a tsunami in Banten and Lampung on Saturday night.

Meteorology, Climatology and Geophysics Agency (BMKG) chairwoman Dwikorita Karnawati said the agency had forecast extreme weather in the area until at least Wednesday.

“Weather forecasts suggest extreme weather, including strong winds and torrential rain, which may trigger high tide and last until at least Wednesday. Residents should not panic but please refrain from conducting any activities near beaches. We will announce later if we think the warning should be extended,” Dwikorita told a joint press conference in Jakarta on Monday.

She further advised residents to always refer to authorized agencies, particularly the BMKG, when seeking reliable information. The authorities will also closely monitor Anak Krakatau, she said.

After studying data and satellite imagery, a joint team involving relevant institutions such as the Coordinating Maritime Ministry, the BMKG and the Geospatial Information Body concluded that Anak Krakatau’s eruptions had led to a material collapse, which triggered tremors equivalent to a magnitude-3.4 earthquake, she explained.

“The eruptions caused what we call an underwater landslide which, within only 24 minutes, triggered a tsunami. The resulting tremors were equivalent to a magnitude-3.4 earthquake with Anak Krakatau as the epicenter,” she said.

More than 90 percent of earthquakes occurring in Indonesia are tectonic earthquakes and the BMKG, the highest authority to manage early warning system, did not have immediate access to data related to volcanic earthquakes.

"It's with another office," she said.

The Sunda Strait tsunami killed at least 281 people and injured more than 1,016 others. At least 57 people have also been declared missing. Meanwhile, local agencies have deployed their personnel to coastal areas in their region.

The Garut Disaster Mitigation Agency (BPBD) in West Java focused particularly on popular tourist destinations, including beaches.

BPBD Garut head Dadi Djakaria said the agency would also closely monitor information from the early warning system, which covers various spots in the region, including the flood-prone Cimanuk River.

“Everything is under control as of now,” he said as quoted by Antara news agency.

Editor: Wahyu T.Rahmawati