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SeismoAtlas

M3.8 earthquake near Honmachi, Kumamoto, Japan

A magnitude 3.8 earthquake struck near Honmachi, Kumamoto, Japan at 23:21 local time (14:21 UTC) on 7 Sept 2026, at a depth of 10 km, according to JMA. The solution is preliminary and may be revised.

Data: JMA · updated 2026-09-07 14:25 UTC · automatic solution

Magnitude
3.8minor
JMA magnitude (Mj)
Depth
10 km
Status
Automatic
Origin time
2026-09-07 14:21:00 UTC
Local: 7 Sept 2026, 23:21:00 (Asia/Tokyo)
Epicentre
32.500° N, 130.600° 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
HonmachiKumamoto, Japan · pop. 123,0670 kmIVLight
WakasuKumamoto, Japan · pop. 11,09412 kmIVLight
UkiKumamoto, Japan · pop. 59,92814 kmIIIWeak
MatsubaseKumamoto, Japan · pop. 26,16318 kmIIIWeak
Ōyanomachi-noboritateKumamoto, Japan · pop. 24,56319 kmIIIWeak
KotōKumamoto, Japan · pop. 543,73034 kmIIIWeak
KumamotoJapan · pop. 738,90735 kmIIWeak
NagasakiJapan · pop. 409,11873 kmIIWeak

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. Likely felt out to about 34 km.

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 Mj10 km32.50° N, 130.60° 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 10 km this was a shallow earthquake, which is felt more strongly at the surface than a deeper one of the same size.

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

40 later earthquakes within 30 km; the largest was M4.0 14 days ago. 15 in the 7 days before. Aftershock rates usually fall off roughly in proportion to 1/time.

Aftershocks

Mainshock M3.8

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

Aftershocks
Time after mainshock (hours)MagnitudeDepth (km)
14.553.510
21.683.310
24.322.610
29.972.810
39.102.910
39.623.010
56.902.90
58.982.510
65.903.10
73.522.310
74.802.510
82.772.810
93.302.610
139.932.310
164.254.00
175.883.010
196.552.610
214.231.00
235.052.30
238.523.210
239.322.910
242.722.520
261.222.310
266.632.810
271.622.510
272.452.510
278.722.710
329.932.310
333.282.00
338.303.50
345.103.010
358.502.510
370.103.310
407.283.010
407.422.710
425.722.00
449.732.10
452.352.60
456.552.20
487.132.810
  1. 4.011 km S of Honmachi, Kumamoto, Japan09-14 10:36
  2. 3.59 km W of Honmachi, Kumamoto, Japan09-08 04:54
  3. 3.54 km ESE of Uki, Kumamoto, Japan09-21 16:39
  4. 3.3Near Honmachi, Kumamoto, Japan09-08 12:02
  5. 3.34 km NE of Uto, Kumamoto, Japan09-23 00:27
  6. 3.24 km W of Wakasu, Kumamoto, Japan09-17 12:52
  7. 3.1Near Honmachi, Kumamoto, Japan09-10 08:15
  8. 3.09 km W of Honmachi, Kumamoto, Japan09-09 05:58
  9. 3.0Near Honmachi, Kumamoto, Japan09-14 22:14
  10. 3.0Near Honmachi, Kumamoto, Japan09-21 23:27
  11. 3.0Near Honmachi, Kumamoto, Japan09-24 13:38
  12. 2.9Near Sashiki, Kumamoto, Japan09-09 05:27
  13. 2.9Near Honmachi, Kumamoto, Japan09-09 23:15
  14. 2.94 km NE of Uto, Kumamoto, Japan09-17 13:40
  15. 2.8Near Honmachi, Kumamoto, Japan09-08 20:19
  16. 2.8Near Mifune, Kumamoto, Japan09-11 01:07
  17. 2.84 km ESE of Uki, Kumamoto, Japan09-18 16:59
  18. 2.89 km W of Honmachi, Kumamoto, Japan09-27 21:29
  19. 2.74 km NE of Uto, Kumamoto, Japan09-19 05:04
  20. 2.74 km NE of Uto, Kumamoto, Japan09-24 13:46
  21. 2.615 km NW of Sashiki, Kumamoto, Japan09-08 14:40
  22. 2.611 km N of Sashiki, Kumamoto, Japan09-11 11:39
  23. 2.6Near Honmachi, Kumamoto, Japan09-15 18:54
  24. 2.6Near Honmachi, Kumamoto, Japan09-26 10:42
  25. 2.5Near Honmachi, Kumamoto, Japan09-10 01:20

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 jma20260907232129. First recorded here 28 Sept 2026, 17:32:06 UTC. Solutions: JMA (jma:20260907232129). Cite as: SeismoAtlas, “M3.8 earthquake near Honmachi, Kumamoto, Japan”, https://seismoatlas.com/earthquake/jma20260907232129-m3-8-earthquake-near-honmachi-kumamoto-japan, data from JMA.

JSON: /api/v1/events/jma20260907232129. SeismoAtlas is not an official warning service.