M4.0 Earthquake 67 km NNE of Ruteng, Indonesia — August 21, 2026
2026-08-21 20:00:51 UTC (2026-08-21) · approx. 4:00 AM UTC+8 local
On August 21, 2026 at 20:00 UTC, a magnitude 4.0 shallow crustal earthquake struck 67 km NNE of Ruteng, Indonesia, at a depth of 10.0 km and coordinates -8.0562°, 120.7237°.
Physical scale: An earthquake of magnitude 4.0 releases seismic energy equivalent to roughly 15 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 347 m — a useful intuition for the size of the slip patch on the fault.
This earthquake is part of an ongoing aftershock sequence following the magnitude 5.1 mainshock that occurred 20 hours ago 67 km NE of Ruteng, Indonesia. Since the mainshock, the USGS has recorded 5 aftershocks in this area. Aftershock activity is expected to continue for days to weeks as stresses on surrounding faults redistribute.
Earthquake Details
120.7237°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 4.0 earthquake near Ruteng, Indonesia?
The magnitude 4.0 earthquake that struck 67 km NNE of Ruteng, Indonesia on August 21, 2026 at 20:00 UTC had a depth of 10.0 km. For context, this was a light earthquake commonly felt near the epicenter.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.0 earthquakes can continue for several days and gradually diminish over time.
Is this the same earthquake as the M5.1 one earlier?
No. This magnitude 4.0 earthquake is an aftershock of the larger magnitude 5.1 mainshock that occurred earlier 67 km NE of Ruteng, Indonesia. Aftershocks are smaller earthquakes triggered by stress changes from the mainshock.
Actions
Understanding This Data
Magnitude 4.0 earthquakes are often felt but rarely cause damage.
Authoritative source: USGS event page (event ID: us7000tcbf). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2026, August 21, 2026). M4.0 Earthquake 67 km NNE of Ruteng, Indonesia — August 21, 2026. Retrieved September 16, 2026 from https://www.earthquaketracker.org/earthquakes/event/us7000tcbf/