Offshore M4.7 quake shakes Manggarai–Komodo hinterland north of Ruteng

Offshore north of Ruteng, Manggarai and Manggarai Barat, Flores — A tectonic earthquake of magnitude 4.7 struck offshore north of Ruteng on Friday night, 18 September 2026, with shaking felt across Manggarai and Manggarai Barat, Indonesia’s meteorology agency BMKG and regional media reported.

According to a BMKG information release cited by Pos-Kupang and other outlets, the quake occurred at about 20:20 WITA (19:20:56 WIB) on 18 September. The epicentre was located in the sea roughly 46 kilometres north of Ruteng, at coordinates near 8.20° south and 120.50° east, and a depth of around 8 kilometres. BMKG stated the event did not generate a tsunami, and classified it as part of the ongoing Flores seismic sequence.

Pos-Kupang reported that BMKG’s shake-map estimates put the intensity at III–IV on the Modified Mercalli Intensity (MMI) scale in Manggarai Regency, where the tremor was widely felt indoors and caused light rattling of household objects. In neighbouring Manggarai Barat, the shaking was reported at around II MMI, felt by some residents and strong enough to make hanging items sway, but below levels typically associated with structural damage.

Coverage by TribunFlores, citing the same BMKG parameters, likewise described the quake as being felt at III MMI across northern Manggarai localities such as Wae Ri’i, Ruteng, Cibal, Reok and surrounding districts, consistent with light to moderate felt shaking but no serious building damage.

The 18 September event followed a magnitude 4.1 earthquake earlier the same afternoon off Ruteng, also linked by BMKG to the Flores sequence. Regional media quoting BMKG analysis said that M4.1 quake struck at 15:22:57 WIB (around 16:22 WITA) at a depth of about 3 kilometres, roughly 54 kilometres north of Ruteng, and was felt at II–III MMI in Manggarai.

In its broader update on seismic activity in East Nusa Tenggara, BMKG stated that the series of aftershocks following the major NTT earthquake in August had surpassed 15,700 events by mid-September. The agency noted that these aftershocks span magnitudes from below 1.0 to above 6.0, with nearly two hundred felt by residents, underscoring the sustained seismic unrest affecting Flores and the wider province.

BMKG’s public advisory, relayed by Pos-Kupang and other outlets, urged residents in Manggarai and Manggarai Barat to remain cautious around structures that had already suffered cracking or other damage in earlier shocks, and to follow guidance from local disaster management authorities. At the same time, the agency called on communities to stay calm, emphasising that frequent small to moderate aftershocks are a normal part of the tectonic adjustment process after a major quake.

For risk modelling and disaster preparedness along the Komodo–Labuan Bajo hinterland and northern Flores coast, the 18 September M4.7 event adds to a growing dataset of shallow offshore quakes on the Flores segment. BMKG and regional media have highlighted that the recent pattern of epicentres north of Ruteng, combined with the high number of recorded aftershocks since August, illustrates the need for continued monitoring, public education on earthquake-safe practices, and attention to building safety in the tourism and conservation areas of western Flores.

Sources

• Pos-Kupang – Gempa Magnitudo 4,7 Guncang Flores, Dirasakan di Manggarai hingga Manggarai Barat
• Katadata Databoks – Gempa Terkini 4,7 M Guncang Ruteng, Manggarai, Ini Penjelasan BMKG