BNPB aerial survey finds minor tsunami impacts after Flores M7.7 quake

Labuan Bajo — The tsunami that followed a magnitude 7.7 offshore earthquake near Mbay, Nagekeo, caused limited physical impacts along the northern coast of Flores, according to Indonesia’s National Disaster Management Agency (BNPB) after an aerial survey on Friday, 21 August 2026.

BNPB’s Deputy for Disaster Mitigation, Abdul Muhari, said the helicopter survey confirmed tsunami inundation at two locations, near Riung and along the boundary between Riung and Nagekeo. The affected areas were generally used as ponds and aquaculture sites rather than dense residential neighbourhoods, and the agency assessed the tsunami impact on settlements and residents as minor.

The survey was carried out seven days after the earthquake, using a helicopter flying along the northern coastline of Flores from Labuan Bajo through Manggarai, East Manggarai, Ngada and Nagekeo. According to BNPB, the flight aimed both to validate reports on tsunami effects and to map logistical access and damage patterns following the main shock.

Quake and warning timeline

The Meteorology, Climatology and Geophysical Agency (BMKG) recorded the main earthquake at 04:58:24 WIB on Saturday, 15 August 2026, with a magnitude of 7.7 and an epicentre about 30 kilometres northeast of Mbay, Nagekeo, at a depth of 15 kilometres. BMKG’s initial automated solution listed a magnitude of 7.0, which was later updated to 7.7.

BMKG issued Tsunami Early Warning 1 at 05:00:39 WIB and Tsunami Early Warning 2 at 05:09:56 WIB, based on tsunami modelling that indicated the quake was capable of generating waves affecting several provinces. The warnings covered coastal areas in East Nusa Tenggara, South Sulawesi, West Nusa Tenggara and Southeast Sulawesi, with threat levels and estimated arrival times communicated through BMKG’s official channels.

At 07:31:30 WIB, BMKG announced that the tsunami early warning triggered by the 7.7 earthquake had ended, stating that the warning “is declared to have ended” for the event located 30 kilometres northeast of Mbay. News outlets quoting BMKG reported that the agency’s system had ceased issuing tsunami alerts while aftershocks continued to be recorded in the wider Flores region.

BNPB’s aerial assessment

In its statement on the aerial survey, BNPB said that, in general, tsunami impacts along the surveyed coastline were minor and did not widely penetrate residential areas. Abdul Muhari, who also serves as a tsunami expert, emphasised that only two broad inundation patches were visible from the air, both in the Riung area and at the Riung–Nagekeo boundary.

BNPB explained that the characteristics of local topography and land use meant the observed inundation mainly affected pond areas, with limited direct consequences for housing and community infrastructure compared with scenarios where waves enter densely populated settlements. The agency positioned the aerial mapping as an initial validation of tsunami reports, to be supplemented by ground surveys to document building damage and support recovery.

Besides checking for tsunami traces, the helicopter mission also mapped access routes for aid distribution, focusing on upland communities where road connections are limited. BNPB said the survey would help identify suitable helicopter drop zones for supplies to residents in hard-to-reach hilltop areas.

Warning and preparedness

BMKG’s tsunami warnings were based on the earthquake’s magnitude, depth and offshore location, which indicated potential wave generation across parts of East Nusa Tenggara and neighbouring provinces. Media reports, citing BMKG data, described “siaga” and “waspada” threat levels for specific coastal districts in Nusa Tenggara and South Sulawesi, with modelled wave heights in the range of 0.5 to 3 metres along some shorelines.

Although BNPB’s subsequent aerial inspection found only two limited inundation points and assessed the overall tsunami impact as minor, authorities underscored that early warnings remain essential for coastal safety whenever a strong, relatively shallow offshore quake occurs. BMKG’s and BNPB’s accounts together show a sequence in which the hazard-based tsunami alerts were issued promptly, followed by field surveys to verify actual coastal effects and support emergency logistics.

Sources

• BNPB official release
• Aktual.com
• BMKG tsunami event page (M7.0)
• Metro TV News
• Liputan6
• CNN Indonesia
• Investortrust.id