M4.9 Earthquake 75 km ESE of Iwaki, Japan — July 20, 2024
2024-07-20 11:15:50 UTC (2024-07-20) · approx. 8:15 PM UTC+9 local
Felt by 7 people across nearby locations.
On July 20, 2024 at 11:15 UTC, a magnitude 4.9 shallow crustal earthquake struck 75 km ESE of Iwaki, Japan, at a depth of 23.6 km and coordinates 36.7116°, 141.6138°. This earthquake was detected by 85 seismic stations with good location accuracy and was assigned a USGS significance rating of 371, placing it among routine seismic activity.
Physical scale: An earthquake of magnitude 4.9 releases seismic energy equivalent to roughly 338 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 1.4 km — a useful intuition for the size of the slip patch on the fault.
The epicenter is located in Japan, a region characterized by the intersection of four tectonic plates — Pacific, Philippine Sea, Eurasian, and North American — creating multiple subduction zones. The nearest mapped fault system is the Japan Trench. View all earthquakes in Japan.
Learn more: Magnitude scale · Aftershock sequences
Did You Feel It? — community-reported shaking
Aggregated felt-report intensity from 7 citizen responses to the USGS Did You Feel It? system. Each colored zone represents the average MMI from reports in that area.
Source: U.S. Geological Survey Did You Feel It?. View on USGS · submit your own report
Earthquake Details
141.6138°E
Technical Information
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Common Questions
How strong was the magnitude 4.9 earthquake near Iwaki, Japan?
The magnitude 4.9 earthquake that struck 75 km ESE of Iwaki, Japan on July 20, 2024 at 11:15 UTC had a depth of 23.6 km. For context, this was a light earthquake commonly felt near the epicenter.
Where did the earthquake occur?
The earthquake epicenter was located at 36.7116°, 141.6138°, which is 75 km ESE of Iwaki, Japan. View all earthquakes in Japan.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.9 earthquakes can continue for several days and gradually diminish over time.
Has Japan had earthquakes this big before?
The largest recorded earthquake in Japan was the M9.1 Tohoku earthquake of March 11, 2011. Today's magnitude 4.9 event is significantly smaller than that historical record.
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Location
Authoritative source: USGS event page (event ID: us7000n0gi). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2024, July 20, 2024). M4.9 Earthquake 75 km ESE of Iwaki, Japan — July 20, 2024. Retrieved September 13, 2025 from https://www.earthquaketracker.org/earthquakes/event/us7000n0gi/