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M3.8 earthquake 15 km SE of Kesennuma, Miyagi, Japan

A magnitude 3.8 earthquake struck 15 km SE of Kesennuma, Miyagi, Japan at 21:10 local time (12:10 UTC) on 4 Sept 2026, at a depth of 70 km, according to JMA. The solution is preliminary and may be revised.

Data: JMA · updated 2026-09-04 12:12 UTC · automatic solution

Magnitude
3.8minor
JMA magnitude (Mj)
Depth
70 km
Status
Automatic
Origin time
2026-09-04 12:10:00 UTC
Local: 4 Sept 2026, 21:10:00 (Asia/Tokyo)
Epicentre
38.800° N, 141.700° E

Circles show this event and others within 30 km from 7 days before to 30 days after. Lines: plate boundaries and GEM active faults. Open on the live map

Nearby places

Distance and estimated shaking at nearby places
PlaceDistanceEst. shaking
KesennumaMiyagi, Japan · pop. 61,14715 kmIIWeak
Rikuzen-TakataIwate, Japan · pop. 18,26225 kmIIWeak
ŌfunatoIwate, Japan · pop. 35,45230 kmINot felt
TomeMiyagi, Japan · pop. 77,89748 kmINot felt
IchinosekiIwate, Japan · pop. 114,47651 kmINot felt
SendaiMiyagi, Japan · pop. 1,096,70493 kmINot felt
MoriokaIwate, Japan · pop. 290,700111 kmINot felt
FukushimaJapan · pop. 294,237159 kmINot felt

Shaking is an estimate from the intensity prediction equation of Allen, Wald & Worden (2012), not an observation. Local ground and buildings can change it by a level or more.

Every agency's solution

Agencies locate earthquakes with their own stations and methods, so their numbers differ. We match reports of the same event by time, distance and magnitude and show them side by side. The headline uses JMA.

AgencyMagnitudeDepthEpicentreTime offsetStatus
JMAheadlineJMA via Japan Meteorological Agency3.8 Mj70 km38.80° N, 141.70° E–Automatic

How big was it?

Often felt by people at rest close to the epicentre, rarely causes damage.

It released roughly the energy of 7.6 t of TNT. Magnitude is logarithmic: each whole step means about 32 times more energy and 10 times larger waves on a seismogram. Depth matters too: at 70 km this was a intermediate-depth earthquake, which spreads shaking over a wider area but less intensely.

M3.8 releases about 32× the energy of M2.8, and its waves are about 10× taller on a seismogram. Energy: 7.6 t of TNT vs 239 kg of TNT.

Each square is the energy of one M2.8. Energy from log₁₀E = 1.5M + 4.8.

Aftershocks and nearby activity

4 later earthquakes within 30 km; the largest was M3.6 20 days ago. Aftershock rates usually fall off roughly in proportion to 1/time.

Aftershocks

Mainshock M3.8

4 later earthquakes nearby. Aftershock rates typically fall off roughly as 1/time (Omori's law).

Aftershocks
Time after mainshock (hours)MagnitudeDepth (km)
68.623.360
91.153.650
208.723.450
575.903.550
  1. 3.631 km SE of Ōfunato, Iwate, Japan09-08 07:19
  2. 3.531 km SE of Ōfunato, Iwate, Japan09-28 12:04
  3. 3.438 km ESE of Kesennuma, Miyagi, Japan09-13 04:53
  4. 3.310 km SE of Ōfunato, Iwate, Japan09-07 08:47

Did you feel it?

Reports from people help show where shaking was strong. They are anonymous and shown here in aggregate.

Reports close 14 days after an earthquake.

Reports on SeismoAtlas

No reports yet.

Event id jma20260904211003. First recorded here 28 Sept 2026, 17:32:06 UTC. Solutions: JMA (jma:20260904211003). Cite as: SeismoAtlas, “M3.8 earthquake 15 km SE of Kesennuma, Miyagi, Japan”, https://seismoatlas.com/earthquake/jma20260904211003-m3-8-earthquake-15-km-se-of-kesennuma-miyagi-japan, data from JMA.

JSON: /api/v1/events/jma20260904211003. SeismoAtlas is not an official warning service.