Magnitude 5.3 quake near Ruteng jolts inland Flores, no tsunami threat

Ruteng — A tectonic earthquake with a magnitude of 5.3 struck inland Flores near Ruteng in Manggarai Regency, East Nusa Tenggara, on 21 September 2026, prompting residents to rush out of homes and offices as the ground shook.

According to the Meteorology, Climatology and Geophysics Agency (BMKG), the quake occurred at a depth of around 10 kilometres with the epicentre on land approximately 34 kilometres northeast of Ruteng, Manggarai Regency.

Regional and national media reports quoting BMKG data state that the shaking was felt across several parts of Flores, including Manggarai, Bajawa and Labuan Bajo, at Modified Mercalli Intensity (MMI) levels III–IV, meaning it was clearly felt indoors and prompted many people to move outside.

Residents in Nagekeo and Waingapu reported feeling lighter shaking at MMI II–III, while people in Maumere experienced weaker tremors at around MMI II, consistent with BMKG’s shakemap estimates.

BMKG’s tsunami modelling for this event confirmed that the earthquake did not generate a tsunami, and officers reiterated that the location and depth of the epicentre meant the tremor did not have the characteristics needed to trigger a tsunami.

Officials from BMKG described the earthquake as a shallow crustal event linked to the Flores Back-arc Thrust system, a major thrust fault that runs east–west north of Flores and has been responsible for significant seismicity in the region.

Local coverage from Manggarai noted that civil servants and other office workers in Ruteng evacuated to building courtyards when the tremor struck on Monday morning, while residents in Manggarai and neighbouring regencies left their houses until the shaking subsided.

BMKG has advised residents in Flores and surrounding islands to remain alert to possible aftershocks but also to continue daily activities as normal, ensuring buildings are structurally sound and following standard earthquake safety procedures.

The agency emphasised that this 5.3-magnitude event forms part of a long aftershock sequence following the major magnitude 7.7 earthquake that struck Flores on 15 August 2026.

By the morning of 21 September, BMKG monitoring indicated tens of thousands of aftershocks had occurred since the August mainshock, with several events strong enough to be felt over a wide area.

As of the latest reports on Monday, authorities and local media had not received information on significant damage or casualties from the 5.3-magnitude quake near Ruteng.

Officials urged the public to rely on official BMKG updates and regional disaster management agencies for information on future seismic activity in Flores and East Nusa Tenggara.

Sources

• DetikBali
• TribunFlores
• VIVA NTT