M4.6 Earthquake 8 km ENE of Omigawa, Japan — July 28, 2020
2020-07-28 20:33:26 UTC (2020-07-28) · approx. 5:33 AM UTC+9 local
Felt by 7 people across nearby locations. Aftershock of the M5.3 mainshock.
On July 28, 2020 at 20:33 UTC, a magnitude 4.6 shallow crustal earthquake struck 8 km ENE of Omigawa, Japan, at a depth of 34.1 km and coordinates 35.8750°, 140.7072°.
Physical scale: An earthquake of magnitude 4.6 releases seismic energy equivalent to roughly 120 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 899 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 5.3 mainshock that occurred 9 days ago 0 km NNE of Yōkaichiba, Japan. Since the mainshock, the USGS has recorded 1 aftershocks in this area. Aftershock activity is expected to continue for days to weeks as stresses on surrounding faults redistribute.
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
140.7072°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 4.6 earthquake near Omigawa, Japan?
The magnitude 4.6 earthquake that struck 8 km ENE of Omigawa, Japan on July 28, 2020 at 20:33 UTC had a depth of 34.1 km. For context, this was a light earthquake commonly felt near the epicenter.
Where did the earthquake occur?
The earthquake epicenter was located at 35.8750°, 140.7072°, which is 8 km ENE of Omigawa, Japan. View all earthquakes in Japan.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.6 earthquakes can continue for several days and gradually diminish over time.
Is this the same earthquake as the M5.3 one earlier?
No. This magnitude 4.6 earthquake is an aftershock of the larger magnitude 5.3 mainshock that occurred earlier 0 km NNE of Yōkaichiba, Japan. Aftershocks are smaller earthquakes triggered by stress changes from the mainshock.
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 4.6 event is significantly smaller than that historical record.
Actions
Location
Authoritative source: USGS event page (event ID: us6000b5lm). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2020, July 28, 2020). M4.6 Earthquake 8 km ENE of Omigawa, Japan — July 28, 2020. Retrieved October 3, 2020 from https://www.earthquaketracker.org/earthquakes/event/us6000b5lm/