M4.3 earthquake 14 km SSE of Asahi, Chiba, Japan
A magnitude 4.3 earthquake struck 14 km SSE of Asahi, Chiba, Japan at 01:24 local time (16:24 UTC) on 12 Oct 2026, at a depth of 50 km, according to JMA and USGS. The solution is preliminary and may be revised.
Reported by 2 agencies
Data: JMA, USGS · updated 2026-10-11 18:05 UTC · automatic solution
- Magnitude
- 4.3light
JMA magnitude (Mj) - Depth
- 50 km
- Status
- Automatic
- Origin time
- 2026-10-11 16:24:00 UTC
- Local: 12 Oct 2026, 01:24:00 (Asia/Tokyo)
- Epicentre
- 35.600° N, 140.700° E
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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
| Place | Distance | Est. shaking |
|---|---|---|
| AsahiChiba, Japan · pop. 64,690 | 14 km | IIIWeak |
| YōkaichibaChiba, Japan · pop. 32,651 | 18 km | IIIWeak |
| ChoshiChiba, Japan · pop. 58,431 | 19 km | IIIWeak |
| HasakiChiba, Japan · pop. 39,209 | 19 km | IIIWeak |
| ChibaJapan · pop. 979,768 | 52 km | IIWeak |
| IchiharaChiba, Japan · pop. 283,531 | 57 km | IIWeak |
| KashiwaChiba, Japan · pop. 433,436 | 71 km | IIWeak |
| MatsudoChiba, Japan · pop. 498,575 | 75 km | IIWeak |
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 33 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.
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How big was it?
Widely felt near the epicentre: rattling windows and objects. Significant damage is unlikely.
It released roughly the energy of 43 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 50 km this was a shallow earthquake, which is felt more strongly at the surface than a deeper one of the same size.
M4.3 releases about 32× the energy of M3.3, and its waves are about 10× taller on a seismogram. Energy: 43 t of TNT vs 1.3 t of TNT.
Each square is the energy of one M3.3. Energy from log₁₀E = 1.5M + 4.8.
Aftershocks and nearby activity
No later earthquakes have been recorded within 30 km so far. 3 in the 7 days before. Aftershock rates usually fall off roughly in proportion to 1/time.
Did you feel it?
Reports from people help show where shaking was strong. They are anonymous and shown here in aggregate.
Reports on SeismoAtlas
No reports yet.
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Event id jma20261012012430. First recorded here 11 Oct 2026, 16:29:01 UTC. Solutions: JMA (jma:20261012012430); USGS (usgs:us6000u1l7). Cite as: SeismoAtlas, “M4.3 earthquake 14 km SSE of Asahi, Chiba, Japan”, https://seismoatlas.com/earthquake/jma20261012012430-m4-3-earthquake-14-km-sse-of-asahi-chiba-japan, data from JMA, USGS.
JSON: /api/v1/events/jma20261012012430. SeismoAtlas is not an official warning service.