BMKG Manado Reports 1,770 Aftershocks After M7.6 Molucca Sea Quake

Manado — The Manado Geophysical Station of Indonesia’s Meteorology, Climatology and Geophysics Agency (BMKG) has recorded 1,770 aftershocks following the magnitude 7.6 earthquake that struck the Molucca Sea between North Sulawesi and North Maluku on 2 April 2026, according to a report by Republika quoting station officials.

The sequence is associated with the major quake off Pulau Batang Dua, Ternate, which BMKG located in the Molucca Sea and classified as a tectonic event. The station’s data coordinator for information and data, Muhammad Zulkifli, said the continued aftershock activity showed that seismicity in the area remained significant.

According to the Manado station, 36 of the recorded aftershocks were felt by residents in Batang Dua, North Maluku. The aftershocks ranged from magnitude 1.7 to 5.8, and 18 events had magnitudes of at least 5.0. BMKG assessments cited by other outlets also describe the largest aftershock in the wider sequence as having a magnitude of 6.2.

BMKG’s monitoring data

Republika reports that the Manado station’s count of 1,770 aftershocks covers earthquakes associated with the 2 April mainshock in the Molucca Sea, and notes that seismic activity in the area remained intense as of the latest monitoring time. An Indonesian-language summary of the 2026 Molucca Sea earthquake similarly states that BMKG recorded at least 1,770 aftershocks after the main event.

Earlier BMKG bulletins documented the rapid growth of the sequence. A BMKG press release on 2 April said that 11 aftershocks had been detected by 06:50 WIB, with the largest measuring magnitude 5.5. Another BMKG communication later the same day reported 93 aftershocks by 12:00 WIB, with magnitudes between 2.8 and 5.8 and seven events being felt. Subsequent media coverage cited BMKG figures of 484 aftershocks by 3 April, 960 aftershocks by 6 April, and 48 felt aftershocks by 3 April.

These progressive counts indicate a sustained aftershock sequence over at least several weeks. A later economic and regional analysis article, drawing on BMKG data, stated that by the end of April 2026 there were 1,958 aftershocks linked to the Batang Dua mainshock, suggesting that the 1,770 figure reported by the Manado station reflects an intermediate stage in the sequence rather than its final total.

Reporting cut-off and timing

Republika attributes the 1,770-aftershock figure to BMKG data compiled "until Monday, 20 April 2026 at 06:00 WIB," while publishing its story on 23 April 2026. The cut-off time corresponds to 07:00 WITA in Manado and 07:00 WIT in Ternate, but the report does not explain whether the count was updated after that time or whether later observations were excluded from that specific total.

Other sources describe the main earthquake as occurring in the morning of 2 April 2026, with magnitudes reported as 7.6 by BMKG and 7.4 by international agencies, and a focal depth revised by BMKG to 18–33 km depending on the bulletin. BMKG initially issued a tsunami warning for parts of North Maluku and North Sulawesi and later declared the warning ended after monitoring sea-level changes and aftershock activity.

Impact and ongoing monitoring

Coverage of the main earthquake and its aftermath reports casualties and damage in several areas of North Sulawesi and North Maluku, but the April 23 Manado station update on 1,770 aftershocks focuses on seismic data and does not detail specific impacts from individual aftershocks. According to BMKG and media summaries, many of the stronger aftershocks were felt in Manado, Bitung, Ternate and surrounding districts with varying Modified Mercalli intensities, but most did not generate tsunami warnings.

BMKG statements cited by national outlets emphasize that aftershocks are expected following a major tectonic earthquake and that residents in affected areas should remain cautious, check building structures and follow official guidance on earthquake and tsunami preparedness. The Manado station’s reporting of 1,770 aftershocks, including 36 felt events and 18 of magnitude 5.0 or higher, underscores the scale of the sequence that followed the 2 April 2026 Molucca Sea earthquake.

Sources

• Republika
• Indonesian-language encyclopedic summary of the 2026 Molucca Sea earthquake
• BMKG press releases on the 2 April 2026 Batang Dua earthquake and its aftershocks
• Detik.com and RRI reports citing BMKG aftershock monitoring
• Warta Ekonomi regional analysis on North Sulawesi seismic activity in April 2026
• Suara.com and RRI English-language report quoting BMKG tsunami bulletin