M4.2 earthquake 40 km NE of Shizunai-furukawachō, Hokkaido, Japan
A magnitude 4.2 earthquake struck 40 km NE of Shizunai-furukawachō, Hokkaido, Japan at 23:41 local time (14:41 UTC) on 21 Oct 2026, at a depth of 100 km, according to JMA and USGS. The solution is preliminary and may be revised.
Reported by 2 agencies
Data: JMA, USGS · updated 2026-11-04 21:14 UTC · automatic solution
- Magnitude
- 4.2light
JMA magnitude (Mj) - Depth
- 100 km
- Status
- Automatic
- Origin time
- 2026-10-21 14:41:00 UTC
- Local: 21 Oct 2026, 23:41:00 (Asia/Tokyo)
- Epicentre
- 42.600° N, 142.700° 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
| Place | Distance | Est. shaking |
|---|---|---|
| Shizunai-furukawachōHokkaido, Japan · pop. 22,436 | 40 km | IIWeak |
| NiikappuHokkaido, Japan · pop. 5,696 | 42 km | IIWeak |
| ObihiroHokkaido, Japan · pop. 166,536 | 54 km | IIWeak |
| OtofukeHokkaido, Japan · pop. 44,235 | 60 km | INot felt |
| SarubetsuHokkaido, Japan · pop. 25,766 | 60 km | INot felt |
| SapporoHokkaido, Japan · pop. 1,973,832 | 122 km | INot felt |
| AsahikawaHokkaido, Japan · pop. 333,530 | 133 km | INot felt |
| HakodateHokkaido, Japan · pop. 275,730 | 185 km | INot 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.
How big was it?
Widely felt near the epicentre: rattling windows and objects. Significant damage is unlikely.
It released roughly the energy of 30 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 100 km this was a intermediate-depth earthquake, which spreads shaking over a wider area but less intensely.
M4.2 releases about 32× the energy of M3.2, and its waves are about 10× taller on a seismogram. Energy: 30 t of TNT vs 951 kg of TNT.
Each square is the energy of one M3.2. Energy from log₁₀E = 1.5M + 4.8.
Aftershocks and nearby activity
No later earthquakes have been recorded within 30 km so far. 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 close 14 days after an earthquake.
Reports on SeismoAtlas
No reports yet.
Event id jma20261021234104. First recorded here 21 Oct 2026, 14:46:18 UTC. Solutions: JMA (jma:20261021234104); USGS (usgs:us6000u3uc). Cite as: SeismoAtlas, “M4.2 earthquake 40 km NE of Shizunai-furukawachō, Hokkaido, Japan”, https://seismoatlas.com/earthquake/jma20261021234104-m4-2-earthquake-40-km-ne-of-shizunai-furukawacho-hokkaido-japan, data from JMA, USGS.
JSON: /api/v1/events/jma20261021234104. SeismoAtlas is not an official warning service.