Strong M6.9 earthquake hits North Sumatra, Indonesia

The epicenter was located 15 km (9 miles) NNW of Pematangsiantar (population 268 254), 20 km (12 miles) W of Pekan Bahapal (population 40 000), 30 km (19 miles) SSW of Tebingtinggi (population 117 530), 50 km (31 miles) N of Parapat (population 10 000), and 70 km (43 miles) SE of Medan (population 2 435 252), North Sumatra, Indonesia.

11.6 million people are estimated to have felt moderate shaking, 4.7 million light, and 24 000 weak.

There is no tsunami threat from this earthquake.

The USGS issued a Green alert for shaking-related fatalities and economic losses. There is a low likelihood of casualties and damage.

Overall, the population in this region resides in structures that are vulnerable to earthquake shaking, though resistant structures exist. The predominant vulnerable building types are informal (metal, timber, GI etc.) and heavy wood frame construction.

Recent earthquakes in this area have caused secondary hazards such as landslides that might have contributed to losses.

Liquefaction triggered by this earthquake is estimated to have affected a significant area, with significant population exposed. Landsliding is estimated to have affected little or no area, with little or no population exposed.

This is the third M6+ earthquake to hit Indonesia in 24 hours, following the deadly M7.7 at 21:58 UTC on August 14 and its M6.1 (USGS) / M6.2 (BMKG) aftershock.

Estimated population exposure to earthquake shaking

Selected cities exposed

Regional seismicity

References:

¹ M6.9 earthquake northern Sumatra, Indonesia – USGS – August 15, 2026

² M6.9 earthquake northern Sumatra, Indonesia – EMSC – August 15, 2026