M4.4 Earthquake in the Izu Islands, Japan region — July 23, 2021
2021-07-23 21:55:49 UTC (2021-07-23) · approx. 6:55 AM UTC+9 local
On July 23, 2021 at 21:55 UTC, a magnitude 4.4 intermediate depth earthquake struck in the Izu Islands, Japan region, at a depth of 151.7 km and coordinates 31.7581°, 139.6253°.
Physical scale: An earthquake of magnitude 4.4 releases seismic energy equivalent to roughly 60 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 655 m — a useful intuition for the size of the slip patch on the fault.
Did You Feel It? — community-reported shaking
Aggregated felt-report intensity from 1 citizen response 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
139.6253°E
Technical Information
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Common Questions
How strong was the magnitude 4.4 earthquake in the Izu Islands, Japan region?
The magnitude 4.4 earthquake that struck in the Izu Islands, Japan region on July 23, 2021 at 21:55 UTC had a depth of 151.7 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 4.4 earthquakes can continue for several days and gradually diminish over time.
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Understanding This Data
Magnitude 4.4 earthquakes are often felt but rarely cause damage.
Authoritative source: USGS event page (event ID: us6000eyip). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, July 23, 2021). M4.4 Earthquake in the Izu Islands, Japan region — July 23, 2021. Retrieved October 3, 2021 from https://www.earthquaketracker.org/earthquakes/event/us6000eyip/