M4.7 Earthquake 34 km WNW of Sibolga, Indonesia — August 23, 2021
2021-08-23 20:59:53 UTC (2021-08-23) · approx. 3:59 AM UTC+7 local
On August 23, 2021 at 20:59 UTC, a magnitude 4.7 intermediate depth earthquake struck 34 km WNW of Sibolga, Indonesia, at a depth of 80.9 km and coordinates 1.9037°, 98.5161°.
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.
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
Earthquake Details
98.5161°E
Technical Information
Common Questions
How strong was the magnitude 4.7 earthquake near Sibolga, Indonesia?
The magnitude 4.7 earthquake that struck 34 km WNW of Sibolga, Indonesia on August 23, 2021 at 20:59 UTC had a depth of 80.9 km. For context, this was a light earthquake commonly felt near the epicenter.
Where did the earthquake occur?
The earthquake epicenter was located at 1.9037°, 98.5161°, which is 34 km WNW of Sibolga, Indonesia. View all earthquakes in Indonesia.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.7 earthquakes can continue for several days and gradually diminish over time.
Has Indonesia had earthquakes this big before?
The largest recorded earthquake in Indonesia was the M9.1 Indian Ocean earthquake of December 26, 2004. Today's magnitude 4.7 event is significantly smaller than that historical record.
Authoritative source: USGS event page (event ID: us7000f2si). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, August 23, 2021). M4.7 Earthquake 34 km WNW of Sibolga, Indonesia — August 23, 2021. Retrieved November 2, 2021 from https://www.earthquaketracker.org/earthquakes/event/us7000f2si/