M5.1 Aftershock Strikes Near Ruteng in Flores Earthquake Sequence

M5.1 Aftershock Strikes Near Ruteng in Flores Earthquake Sequence

Reporter

September 8, 2026 | 02:08 pm

TEMPO.CO, Jakarta - A magnitude 5.1 earthquake struck off the coast northeast of Ruteng in Manggarai, East Nusa Tenggara, on Tuesday, September 8, 2026, according to Indonesia’s Meteorology, Climatology and Geophysical Agency (BMKG).

The earthquake occurred at 11:40 a.m. local time at a depth of 10 kilometers, with the epicenter located offshore about 57 kilometers from Ruteng.

BMKG Director of Earthquake and Tsunami Wijayanto said the earthquake was not expected to trigger a tsunami.

“Modeling results show that this earthquake has no tsunami potential,” Wijayanto said in a written statement shortly after the quake.

Linked to Flores Back-Arc Thrust

Wijayanto said the shallow earthquake was caused by activity along the Flores Back-Arc Thrust, a fault system north of Flores Island. BMKG identified the earthquake’s mechanism as a thrust fault, in which one section of the Earth’s crust moves upward relative to another.

Based on BMKG’s estimated shaking intensity map, the earthquake reached intensity IV on the Modified Mercalli Intensity (MMI) scale in Lamba Leda in East Manggarai, as well as Reok and West Reok in Manggarai.

At intensity IV, an earthquake can be felt by many people indoors, while some objects may rattle.

Part of August Earthquake Sequence

BMKG classified Tuesday’s earthquake as part of the aftershock sequence following the magnitude 7.7 earthquake that struck Flores on August 15.

As of September 8, BMKG had recorded 13,591 aftershocks from the August earthquake sequence. The strongest aftershock so far measured magnitude 6.2.

Wijayanto said BMKG would continue monitoring seismic activity in the region and provide updates as needed.

The agency urged residents to remain calm during earthquakes and avoid spreading or believing unverified information.

“Avoid buildings that have cracks or have been damaged by earthquake shaking,” Wijayanto said.

Read: Why Are Several Indonesian Volcanoes Erupting at the Same Time?

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