On Friday Evening a Significant M5.4 Earthquake struck in the North Pacific Ocean 186km from Yokosuka (Japan).

Written by Earthquakelist.org on August 21st, 2026.

In the North Pacific Ocean 186 kilometer from Yokosuka, Japan, a significant MAG-5.4 earthquake occurred in the evening of Friday August 21st, 2026. Around 8 million people have been exposed to shaking.

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Earthquake Summary

This earthquake hit under water in the North Pacific Ocean, 141 kilometers (87 mi) off the coast of Japan, 186 kilometer south of Yokosuka in Kanagawa. The center of this earthquake had a quite shallow depth of 62 km. Shallow earthquakes usually have a larger impact than earthquakes deep in the earth.

Date and Time:	Aug 21, 2026 21:02 (Tokyo Time) - Aug 21, 2026 12:02 Universal Time.
Location:	186 km south of Yokosuka, Kanagawa, Japan. Coordinates 33°43'2"N 140°22'49"E.
Map:	Map of area around epicenter. Click to open in Google Maps.
Magnitude:	MAG 5.4 Detected by 21 stations. Maximum Error Range ±0.068 .
Depth:	62 km (38 mi) A quite shallow depth.
Max. Intensity:	IV Light On the Modified Mercalli Scale.
Tsunami Risk:	Low tsunami risk Earthquakes under MAG-6.5 do not usually cause tsunami's. Always stay cautious - More info here.

Minimal impact predicted

Based on scientific estimates by the US Geographic Survey (USGS), the risk of high fatalities for this earthquake is classified at level GREEN (low). They expect an 90% likelyhood of between 0 and 1 fatalities.

The USGS classifies the economic impact of this earthquake at level GREEN (low). They expect an 90% likelyhood of between 0 and 1 million US Dollars in economic damage and impact.

Roughly 8 million people exposed to shaking

The USGS has published a report estimating the number of people exposed to this earthquake. Acoording to their analysis, roughly 8 million have been exposed to shaking at an MMI level of II or higher.

An estimated 7,760 people were exposed to level IV. At this level, light shaking and likely no damage can be expected. Intensity level III was experienced by the majority of people (around 8 million). In their region, weak shaking and probably no damage can be expected. All exposure to shaking was within the borders of Japan .

Nearby towns and cities

This earthquake may have been felt in Japan . The closest significant population center near the earthquake is Tateyama in Chiba, Japan. Tateyama is located 148 kilometer (92 mi) south of the epicenter. The intensity of shaking and damage in Tateyama is estimated to be around level III on the Modified Mercalli Intensity scale (weak shaking, probably no damage).

Multiple major population centers exist within 300km of the earthquake that struck today. Tokyo is located 228 km to the north (intensity unknown, possibly low). Yokohama is located 202 km to the north and experienced an intensity of III (weak shaking, probably no damage). Kawasaki is located 210 km to the north (intensity unknown, possibly low).

The table below provides an overview of all places in proximity of today's earthquake. Where available, the estimated intensity on the Modified Mercalli Intensity Scale in each place is included. Places where this information is omitted likely experienced little impact.

Overview of nearby places

Earthquake Intensity Map

The maximum intensity (MMI Scale) caused by this earthquake is IV. The map below shows in which areas this earthquake was the most and least impactful. It is based on data from the US Geographic Survey.

I Not felt

II Weak

III Weak

IV Light

V Moderate

VI Strong

VII Very Strong

VIII Severe

IX Violent

X Extreme

Shaking reported by 8 people

People that feel an earthquake may report their experience to the US Geographic Survey. Currently, 8 people have reported shaking in 5 places, all within Japan.We keep updating this article as more ground reports become available. You may report that you felt this earthquake here.

Places with most reports:

• Tokyo, Tokio, Japan: 3 people.
• Yokosuka, Kanagawa, Japan: 2 people.
• Kamakura, Kanagawa, Japan: 1 person.
• Zushi, Kanagawa, Japan: 1 person.
• Kawasaki, Kanagawa, Japan: 1 person.

Risk of aftershocks?

We have not yet detected any foreshocks or aftershocks (MAG-2.5 or higher) within 100km (62 mi) of this earthquake.

Earthquakes can create aftershocks. These are generally at least 1 magnitude lower than any main shock, and as time passes the chance and strength of aftershocks decreases.

The chance that a significant earthquake like this one is followed by an even larger earthquake is not so large. On average, scientists estimate a 94% chance that a major earthquake will not be followed by an even larger one. It is still adviced to be aware of this risk

Earthquakes like this happen often in the region

Earthquakes of this strength are very common in the region. This is the strongest earthquake to hit since June 26th, 2026, when a 5.8 magnitude earthquake hit 220 km (137 mi) further north. An even stronger magnitude 6.3 earthquake struck on July 27th, 2019.

In total, 41 earthquakes with a magnitude of 5.4 or higher have been registered within 300km (186 mi) of this epicenter in the past 10 years. This comes down to an average of once every 3 months.

Low tsunami risk

Based on early data it appears this earthquake was not strong enough (lower than MAG-6.5) to be likely to cause destructive tsunami's. However this earthquake appeared to have hit at a shallow depth under sea, so stay cautious and monitor advice from local authorities.

Tsunami Risk Factors

Sources

Last updated 21/08/26 19:58 (). As more information on this earthquake becomes available this article will be updated. This article is automatically composed based on data originating from multiple sources.

1. US Geographic Society (USGS): Earthquake us6000tmfe
2. European-Mediterranean Seismological Centre (EMSC): Earthquake 20260821_0000261
3. Geonames.org: World Cities Database
4. Google Maps: Static API
5. Earthquakelist.org: Historic Earthquakes Database

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