Shallow M5.6 AFTERSHOCK struck on Monday Afternoon in the North Pacific Ocean 181km from Morioka (Japan).

Written by Earthquakelist.org on April 20th, 2026.

A shallow and significant Magnitude 5.6 aftershock struck in the North Pacific Ocean 181 kilometer from Morioka, Japan in the late afternoon of Monday April 20th, 2026. Shaking may have been felt by a total of 2.3 million people.

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Earthquake Summary

This earthquake hit under water in the North Pacific Ocean, 133 kilometers (82 mi) off the coast of Japan, 181 kilometer east of Morioka in Iwate. The center of this earthquake had a very shallow depth of 25 km. Shallow earthquakes usually have a larger impact than earthquakes deep in the earth.

Date and Time:	Apr 20, 2026 17:32 (Tokyo Time) - Apr 20, 2026 08:32 Universal Time.
Location:	181 km east of Morioka, Iwate, Japan. Coordinates 39°38'21"N 143°15'33"E.
Map:	Map of area around epicenter. Click to open in Google Maps.
Magnitude:	MAG 5.6 Detected by 39 stations. Maximum Error Range ±0.095 .
Depth:	25 km (15 mi) A very 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 2.3 million people exposed to shaking

An estimated 2.3 million have been exposed to shaking (An MMI or Modified Mercalli Intensity level II or higher) as a result of this earthquake according scientific estimates published by the USGS.

Weak shaking and probably no damage may have been experienced by an estimated 2,028,000 people. At III, it is the highest MMI level this earthquake has caused. All exposure to shaking was within the borders of Japan .

Nearby towns and cities

This earthquake may have been felt in Japan . Miyako in Iwate, Japan is the nearest significant place from the epicenter. The earthquake occurred 113 kilometer (70 mi) east of Miyako. Miyako experienced an earthquake intensity (MMI Scale) of roughly III. That level implies weak shaking and probably no damage.

Multiple major population centers exist within 300km of the earthquake that struck today. Sendai is located 257 km to the southwest (intensity unknown, possibly low). Morioka is located 181 km to the west and experienced an intensity of III (weak shaking, probably no damage). Hachinohe is located 178 km to the northwest and experienced an intensity of III (weak shaking, probably no damage).

A complete list of nearby places is included below. Estimated intensity data (MMI) sourced from a shake-map published by the US Geographic Survey is shown where available (cities without data probably experienced little impact).

Overview of nearby places

Earthquake Intensity Map

The intensity in shaking and damage by this earthquake is illustrated through the map below. The highest intensity measured for this earthquake is III.

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 1 person

People that feel an earthquake may report their experience to the US Geographic Survey. Currently, 1 person has reported shaking in one place in 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:

• Hamamatsu, Shizuoka, Japan: 1 person.

This is likely an aftershock

This earthquake was an aftershock. A larger mag. 7.4 earthquake struck 39 km (24 mi) northwest in advance of this 5.6 earthquake around 40 mins earlier.

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 happen often in the region

Earthquakes of this strength are very common in the region. In total, 50 earthquakes with a magnitude of 5.6 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 2 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 20/04/26 09:28 (). This article is automatically generated based on available data. We keep checking multiple sources for additional information. This article gets updated as new details on this earthquake become available.

1. US Geographic Society (USGS): Earthquake us6000srih
2. European-Mediterranean Seismological Centre (EMSC): Earthquake 20260420_0000125
3. Geonames.org: World Cities Database
4. Google Maps: Static API
5. Earthquakelist.org: Historic Earthquakes Database

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