M 5.2 Aftershock Shakes Ruteng, East Nusa Tenggara on Sunday Morning

A magnitude 5.2 earthquake shook the Ruteng area of Manggarai, East Nusa Tenggara (NTT), on Sunday morning (16/8).

According to the Meteorology, Climatology and Geophysics Agency (BMKG), the quake occurred at 06.12 WIB. The epicentre was located 84 kilometres northeast of Ruteng-Manggarai, NTT, and the earthquake did not have the potential to trigger a tsunami.

“Earthquake Mag:5.2, 16-Aug-26 06:12:54 WIB, Loc:7.87 S, 120.64 E (84 km NE of RUTENG-MANGGARAI-NTT), Depth:10 Km, no tsunami potential,” BMKG wrote in a post on its official social media account X @infoBMKG on Sunday.

BMKG estimates that aftershock activity from the Flores Back Arc Thrust will continue for the next two to three weeks before undergoing natural decay.

BMKG recorded 235 aftershocks as of Saturday (15/8) at 14.00 WIB, following the M 7.7 mainshock that struck north of Flores Island, East Nusa Tenggara (NTT), in the morning.

The aftershocks are distributed to the north of Flores Island with magnitudes ranging from M 2.5 to M 6.2.

BMKG monitoring graphs show that the current aftershock trend has not yet experienced significant decay.

“BMKG estimates that the natural decay process will take between 2 and 3 weeks, following the pattern of previous damaging earthquake records in North Maluku,” said BMKG Head Teuku Faisal Fathani in a statement on Saturday (15/8).

Faisal said his agency will continue to monitor the fault’s movement in real-time.

Based on the history and characteristics of the region, he said, the fault stabilisation process requires a certain amount of time before seismic activity returns to normal.

Faisal said the M 7.7 mainshock, centred at a depth of 15 kilometres, was a shallow earthquake triggered by activity on the Flores Back Arc Thrust.

Historically, this structure has a long record of damaging earthquakes. One of them was the M 7.8 earthquake at a depth of 28 kilometres that shook the region in 1992.