M5.5 Earthquake: 75 km S of Yonakuni, Japan

Updated 09:06 UTC · 29 Oct 2026

A magnitude 5.5 earthquake struck 75 km S of Yonakuni, Japan at 05:00 UTC on 30 Sep 2026, at a depth of 10 km, reported by USGS. USGS PAGER issued a green alert: little or no damage and a low chance of deaths. USGS did not set a tsunami flag for this quake. So far 2 aftershocks of M2.5+ have been recorded within 50 km, the largest a M4.5.

M5.5

Magnitude (USGS)

mww

10 km

Depth

shallow

GREEN

USGS PAGER impact alert

estimated impact

Aftershocks M2.5+ so far

within 50 km

[ fig. 1 ] M5.5 EPICENTRE, AFTERSHOCKS AND PAST QUAKESThis quakeAftershock M5+AftershockPast M6+

USGS · updated 09:06 UTC 2026-10-29Tap a point for details · pinch or ctrl + scroll to zoomTrack this live in the app ›

Nearest places

Yonakuni, Okinawa, Japan76 km from the epicentre · quake was S of here · population 1,68476 KM
Hualien City, Taiwan, Taiwan134 km from the epicentre · quake was E of here · population 350,468134 KM
Ishigaki, Okinawa, Japan142 km from the epicentre · quake was WSW of here · population 44,802142 KM
Yilan, Taiwan, Taiwan158 km from the epicentre · quake was SE of here · population 94,188158 KM
Zhongxing New Village, Taiwan, Taiwan226 km from the epicentre · quake was E of here · population 25,549226 KM
Keelung, Taiwan190 km from the epicentre · quake was SE of here · population 362,000190 KM
Xizhi, Taiwan190 km from the epicentre · quake was SE of here · population 205,000190 KM
Neihu, Taiwan195 km from the epicentre · quake was SE of here · population 275,000195 KM
Taipei, Taiwan197 km from the epicentre · quake was SE of here · population 7,872,000197 KM

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Strongest aftershocks so far

Key context

Tectonic setting

Taiwan collision zone. Taiwan is being built by the collision of the Philippine Sea Plate with the edge of the Eurasian Plate at about 8 cm per year. The east coast near Hualien is the most active part; the M7.7 Chi-Chi quake of 1999 and the M7.4 Hualien quake of 3 April 2024 were the largest recent events.

The USGS moment tensor shows strike-slip faulting: the two sides of the fault slid sideways past each other.

At 10 km it was a very shallow quake: shallow quakes shake the ground above them hardest, so local damage depends on how close towns are.

Shaking and impact

USGS PAGER estimates the impact from the shaking and the number of people exposed. For this quake it issued a green alert: little or no damage and a low chance of deaths (fatality alert: green, economic loss alert: green). PAGER is an early estimate and can change as reports come in.

The USGS ShakeMap estimates the strongest shaking at intensity IV on the Modified Mercalli scale (light).

11 people sent a "Did You Feel It?" report to USGS, with the strongest reported intensity IV (light).

Aftershocks

This page counts quakes of M2.5 or more within 50 km after the main shock, from the USGS catalog (last checked 09:06 UTC, 29 Oct 2026): 2 aftershocks so far.

Aftershocks are normal after a quake of this size. They usually become less frequent over days and weeks, but a strong aftershock can still happen, and in a few sequences a later quake is larger. No one can predict their exact time or size; follow the official agency for your area.

Earthquake history within 250 km

Since 1976, USGS lists 912 quakes of M5 or more within 250 km of this epicentre, about 18 a year. Since 1900 the same circle had 587 quakes of M5.5 or larger.

Largest earlier quakes within 250 km, USGS catalog since 1900 (M6+).
Magnitude	Place (USGS)	Date	Depth
M8.2	1920 Hualien, Taiwan Earthquake	1920-06-05	20 km
M7.8	Taiwan	1951-11-24	30 km
M7.7	21 km S of Puli, Taiwan	1999-09-20	33 km
M7.7	50 km SSE of Yilan, Taiwan	1922-09-01	20 km
M7.5	38 km SW of Yonakuni, Japan	1966-03-12	25 km
M7.5	58 km SSW of Hualien City, Taiwan	1951-10-21	25 km
M7.4	15 km S of Hualien City, Taiwan	2024-04-02	40 km
M7.4	85 km ENE of Hengchun, Taiwan	1978-07-23	17 km

Official information

Japan Meteorological Agency (JMA)
EMSC (European-Mediterranean Seismological Centre)
USGS event page for this quake (ShakeMap, PAGER, felt reports)
tsunami.gov for US tsunami bulletins

Data status

USGS review status: reviewed. Magnitude type: mww. USGS last updated this event on 20 Oct 2026 at 07:06 UTC. Magnitude, depth and location can still be revised; this page keeps the same address if they change.

Questions and answers

How strong was the earthquake near Yonakuni, Japan?

USGS measured it at magnitude 5.5 (mww), 10 km deep. The strongest estimated shaking was intensity IV (light). Quakes of M5 to 5.9 are classed as moderate.

Was there a tsunami?

USGS did not set a tsunami flag for this quake. If you are on a coast and feel strong or long shaking, move to high ground anyway, and follow local officials.

Was the earthquake felt?

Yes. 11 people reported it to USGS "Did You Feel It?", with reports up to intensity IV.

Will there be more aftershocks?

Aftershocks are likely to continue for days to weeks, becoming less frequent over time. So far 2 aftershocks of M2.5+ have been listed. Most sequences do not produce a larger quake, but some do. No one can predict the time or size of the next one; follow Japan Meteorological Agency (JMA).

What should I do after a strong earthquake?

Expect aftershocks: Drop, Cover and Hold On when shaking starts again. Check for injuries and damage, stay out of damaged buildings, and use text messages instead of calls so emergency lines stay free. On a coast, move to high ground after strong shaking. Follow your local officials.

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Sources

USGS event page: magnitude, location, ShakeMap, PAGER and Did You Feel It? data for this event. Public domain. Credit: U.S. Geological Survey.
USGS ComCat (FDSN event web service): the USGS earthquake catalog, used for the 30-year counts, history and aftershocks. Public domain. Credit: U.S. Geological Survey.
USGS Geoserve: nearest places to the epicentre.
GeoNames: large-city coordinates, CC BY 4.0.

Page built 09:06 UTC, 2026-10-29. Full list: data sources and method.