M4.7 Earthquake 45 km NNE of Ruteng, Indonesia — August 20, 2026

On August 20, 2026 at 02:24 UTC, a magnitude 4.7 shallow crustal earthquake struck 45 km NNE of Ruteng, Indonesia, at a depth of 10.0 km and coordinates -8.2293°, 120.6074°. This earthquake was detected by 20 seismic stations with good location accuracy and was assigned a USGS significance rating of 340, placing it among routine seismic activity.

Physical scale: An earthquake of magnitude 4.7 releases seismic energy equivalent to roughly 169 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 1.1 km — a useful intuition for the size of the slip patch on the fault.

Active aftershock sequence: This earthquake is the mainshock of an ongoing aftershock sequence. In the 46 hours since the mainshock, the USGS has recorded 10 aftershocks within 20 km of the epicenter, including 10 of magnitude 3.0 or greater. The strongest aftershock was a magnitude 5.7 event 1 day ago. Aftershock sequences from mainshocks of magnitude 4.7 typically continue for several days and gradually diminish over time, though occasional larger aftershocks remain possible.

The epicenter is located in Indonesia, a region characterized by the convergence of the Indo-Australian, Eurasian, and Philippine Sea plates, forming the Sunda-Banda arc system. The nearest mapped fault system is the Sunda megathrust. View all earthquakes in Indonesia.

Learn more: Magnitude scale · Aftershock sequences