NORTH SUMATRA / RankWire.AI / – On Tuesday, an offshore earthquake measuring 6.1 in magnitude impacted the waters near Indonesia’s North Sumatra province, causing tremors felt across various parts of Sumatra. The seismic event occurred at 1:02:23 p.m. western Indonesian time, which corresponds to 06:02:23 UTC. Its epicenter was located approximately 147 kilometers southeast of South Nias Regency. Officials determined the earthquake’s depth to be 29 kilometers beneath the waters west of Sumatra.

The BMKG, Indonesia’s Meteorology, Climatology and Geophysics Agency, identified the epicenter at 0.65 degrees south latitude and 98.32 degrees east longitude. The agency reported the most intense shaking at intensity IV in North Tapanuli. Several other areas in West Sumatra also experienced tremors, with Padang, Padang Pariaman, Pariaman, West Pasaman, and Agam reporting shaking between intensity III and IV.
Communities located farther from the epicenter experienced lower levels of shaking. Padang Sidempuan, Subulussalam, and South Nias reported intensity III. Meanwhile, Padang Panjang and Central Tapanuli experienced shaking at levels II to III, and Gunungsitoli recorded intensity II. The National Disaster Mitigation Agency, known as BNPB, confirmed that the earthquake was not capable of triggering a tsunami. Authorities are actively assessing the affected communities following the seismic event.
No tsunami warning issued following the quake
In South Nias, residents described the tremors as weak, lasting approximately three to five seconds. Local disaster response teams began monitoring the situation and coordinating inspections in areas where the quake was felt. Initial official reports did not indicate any fatalities, injuries, or property damage. Officials are still gathering reports from local authorities as part of the standard procedure after offshore seismic activity.
The earthquake impacted a large area, with tremors felt across multiple parts of western Indonesia. The intensity varied by location, with stronger shaking observed nearer to parts of North Sumatra and West Sumatra. No tsunami warning followed the magnitude 6.1 event. Subsequent official updates confirmed the earthquake’s magnitude, depth, and offshore location remained consistent with initial measurements.
Response teams continue assessments in affected zones
The earthquake near South Nias is among the significant seismic events recorded in Indonesia on August 18. Its offshore epicenter kept the main shock away from densely populated areas, though residents across several districts still reported feeling the tremors. Monitoring efforts persisted in zones that experienced moderate shaking, with authorities prioritizing the collection of verified data regarding local impacts, reaffirming the assessment that no tsunami threat was present.
Indonesia regularly encounters earthquakes due to its position atop multiple active tectonic boundaries. The event on Tuesday struck west of Sumatra, a region with a history of seismic activity. Confirmed by authorities at magnitude 6.1 with a depth of 29 kilometers, the earthquake’s epicenter was identified as 147 kilometers southeast of South Nias, and official assessments indicated there was no tsunami risk associated with this offshore seismic event.