Strong M6.1 Earthquake struck on Friday Evening in the North Pacific Ocean near Chiba (Japan).

Written by Earthquakelist.org on May 26th, 2023. Last updated July 25th, 2023.

In the North Pacific Ocean 38 kilometer from Chiba, Japan, a strong Magnitude 6.1 earthquake occurred in the evening of Friday May 26th, 2023. The earthquake struck near a very densely populated region. Shaking may have been felt by a total of 46 million people.

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Earthquake Summary

This earthquake hit under water in the North Pacific Ocean, right off the coast of Japan (3 mi offshore), 38 kilometer east of Chiba. The center of this earthquake had a quite shallow depth of 42 km. Shallow earthquakes usually have a larger impact than earthquakes deep in the earth.

Date and Time:	May 26, 2023 19:03 (Tokyo Time) - May 26, 2023 10:03 Universal Time.
Location:	38 km east of Chiba, Japan. Coordinates 35°31'46"N 140°31'41"E.
Map:	Map of area around epicenter. Click to open in Google Maps.
Magnitude:	MAG 6.1 Detected by 66 stations. Maximum Error Range ±0.038 .
Depth:	42 km (26 mi) A quite shallow depth.
Max. Intensity:	V Moderate 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

The US Geographic Survey (USGS) describes the impact of this earthquake as follows:

One house damaged at Asahi.

Based on scientific estimates by the USGS, the risk of high fatalities for this earthquake is classified at level GREEN (low). They expect an 65% likelyhood of between 0 and 1 fatalities, and a 96% chance that the number of fatalities falls no higher than 10.

The USGS classifies the economic impact of this earthquake at level GREEN (low). They expect an 65% likelyhood of between 0 and 1 million US Dollars in economic damage and impact, and a 96% chance that the economic impact of this earthquake falls no higher than 10 million USD.

Roughly 46 million people exposed to shaking

This earthquake may have been felt by around 46 million people. That is the expected population size of the area exposed to a level of shaking of II or higher on the Modified Mercalli scale according to the USGS.

Moderate shaking and very light damage may have been experienced by an estimated 230,800 people. At V, it is the highest MMI level this earthquake has caused. The majority of people (roughly 27 million) live in an area exposed to level IV, where light shaking and likely no damage is expected. All exposure to shaking was within the borders of Japan .

Nearby towns and cities

This earthquake may have been felt in Japan . Located 13 kilometer (8 mi) south-east of the epicenter of this earthquake, Narutō (Chiba, Japan) is the nearest significant population center. The intensity of shaking and damage in Narutō is estimated to be around level V on the Modified Mercalli Intensity scale (moderate shaking, very light damage).

Multiple major population centers exist within 300km of the earthquake that struck today. Tokyo is located 78 km to the west-northwest and experienced an intensity of III (weak shaking, probably no damage). Yokohama is located 80 km to the west and experienced an intensity of IV (light shaking, likely no damage). Chiba is located 38 km to the west and experienced an intensity of IV (light shaking, likely no damage).

An overview of nearby towns and cities is available in the overview below. If places don't have intensity data available, it likely means the experienced impact in those places was fairly small.

Overview of nearby places

Earthquake Intensity Map

The maximum intensity (MMI Scale) caused by this earthquake is V. 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 188 people

People that feel an earthquake may report their experience to the US Geographic Survey. Currently, 188 people have reported shaking in 71 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: 53 people.
• Yokohama, Kanagawa, Japan: 8 people.
• Kawasaki, Kanagawa, Japan: 8 people.
• Sōka, Saitama, Japan: 5 people.
• Chiba, Chiba, Japan: 5 people.
• Narashino, Chiba, Japan: 5 people.
• Urayasu, Chiba, Japan: 5 people.
• Komae, Tokio, Japan: 5 people.
• Kawaguchi, Saitama, Japan: 4 people.
• Saitama, Saitama, Japan: 4 people.

8 Aftershocks detected

Since this main shock, 8 smaller aftershocks were detected. A 4.6 magnitude earthquake hit 3 days later 34 km (21 mi) east-northeast of this earthquake.

In the days before this main shock, 1 smaller foreshock was detected. Nearby this earthquake a foreshock struck 1 day earlier. It measured a magnitude of 4.3

Overview of foreshocks and aftershocks

More earthquakes coming?

The risk of aftershocks decreases rapidly over time. Usually, aftershocks are at least one order of magnitude lower than a main shock.

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 are common in the region

Earthquakes of this strength occur quite regularly in the region. This is the strongest earthquake to hit since March 16th, 2022, when a 7.3 magnitude earthquake hit 260 km (162 mi) further north-northeast. That was also the heaviest earthquake to hit the region in the past 10 years.

In total, 7 earthquakes with a magnitude of 6.1 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 year.

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 25/07/23 00:57 (). This article contains currently available information about the earthquake and is automatically composed. We continue to update this article up to a few days after the earthquake occurred.

1. US Geographic Society (USGS): Earthquake us7000k46f
2. European-Mediterranean Seismological Centre (EMSC): Earthquake 20230526_0000090
3. Geonames.org: World Cities Database
4. Google Maps: Static API
5. Earthquakelist.org: Historic Earthquakes Database

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