Indonesia's BMKG Identifies Cause of Magnitude 7.7 NTT Earthquake

An earthquake with a magnitude of 7.7 struck Nusa Tenggara Timur (NTT), Indonesia, on Saturday, August 15, 2026. The Meteorology, Climatology, and Geophysics Agency (BMKG) stated that the tremor was triggered by an active thrust fault in the Flores back-arc region. This geological feature has the capacity to generate earthquakes as strong as magnitude 7.8 to 7.9.

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This is a thrust fault mechanism earthquake in the Flores back-arc region.

BMKG Director of Earthquakes and Tsunamis, Wijayanto, explained that the 7.7 magnitude quake resulted from the thrust fault mechanism. He noted that the 7.7 magnitude event is one of the largest recorded for this area, approaching its maximum potential. "So in the Flores back-arc, there is potential for earthquakes with a maximum of 7.8-7.9. Today it released 7.7," Wijayanto stated during a press conference.

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So in the Flores back-arc, there is potential for earthquakes with a maximum of 7.8-7.9. Today it released 7.7.

Wijayanto also highlighted the region's history of significant seismic activity. He recalled a major earthquake in 1992 with a magnitude of approximately 7.5. "From the history that exists, this happened in 1992, it was magnitude 7.5. That was also a very extraordinary event at the time. So it has been almost 30 years since it happened again," he said. Personnel from the Maumere SAR Office were seen evacuating victims from collapsed buildings in Mbay, Nagekeo, NTT, following the earthquake.

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From the history that exists, this happened in 1992, it was magnitude 7.5. That was also a very extraordinary event at the time. So it has been almost 30 years since it happened again.