M4.5 Earthquake 91 km ENE of Amahai, Indonesia — October 17, 2021
2021-10-17 22:04:31 UTC (2021-10-17) · approx. 7:04 AM UTC+9 local
On October 17, 2021 at 22:04 UTC, a magnitude 4.5 shallow crustal earthquake struck 91 km ENE of Amahai, Indonesia, at a depth of 10.0 km and coordinates -2.9323°, 129.6368°.
Physical scale: An earthquake of magnitude 4.5 releases seismic energy equivalent to roughly 85 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 767 m — 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
129.6368°E
Technical Information
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Common Questions
How strong was the magnitude 4.5 earthquake near Amahai, Indonesia?
The magnitude 4.5 earthquake that struck 91 km ENE of Amahai, Indonesia on October 17, 2021 at 22:04 UTC had a depth of 10.0 km. For context, this was a light earthquake commonly felt near the epicenter.
Where did the earthquake occur?
The earthquake epicenter was located at -2.9323°, 129.6368°, which is 91 km ENE of Amahai, Indonesia. View all earthquakes in Indonesia.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.5 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 4.5 event is significantly smaller than that historical record.
Authoritative source: USGS event page (event ID: us6000fwgu). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, October 17, 2021). M4.5 Earthquake 91 km ENE of Amahai, Indonesia — October 17, 2021. Retrieved December 25, 2021 from https://www.earthquaketracker.org/earthquakes/event/us6000fwgu/