Reported by USGS today.
It is the only one we have recorded within 20 km of this point since 5 September 2026.
What the source measured
USGS reported: 20 km E of Castle Rock, Washington
USGS recorded magnitude 3.9 at a depth of 17 km.
The seismic region given by the source is 20 km E of Castle Rock, Washington.
This is the highest magnitude we have recorded at this point, over 12 readings since 5 September 2026 — the previous range was 3.83 to 3.94.
How we know
One source: USGS. Not yet confirmed by a second, independent source.
Our own score for this event is 0 out of 100, at 50 % confidence.
The score is ours, computed from intensity, exposed population and local history — not the source’s.
Computed under scoring rules v4. Rows carrying other versions were judged by different rules and are not directly comparable.
Event Data
| Type | Earthquakes |
| Severity | Low |
| Calamity Score (ours) | 0 / 100 |
| Our confidence | 50% |
| Coordinates | 46.2450, -122.6448 |
| Nearest City | Longview (26 km) |
| Impact Tier | minor |
| Timestamp | 2026-09-05T11:09:28.290Z |
| Source | https://earthquake.usgs.gov/earthquakes/eventpage/uw714095342 |
Score Breakdown
Technical Details
| Mag | 3.94 |
| Depth | 17.18 |
| Sig | 415 |
| Tsunami | false |
| Region | 20 km E of Castle Rock, Washington |
| Usgs Mag | 3.94 |
| Usgs Depth | 17.18 |
| Usgs Tsunami | false |
| Usgs Felt | 453 |
| Usgs Mmi | 3.6 |
| Usgs Sig | 415 |
| Usgs Dyfi Mag | 3.94 |
| Usgs Dyfi Depth | 17.18 |
| Usgs Dyfi Felt | 453 |
| Usgs Dyfi Cdi | 3.9 |
| Usgs Dyfi CdiDescription | Weak |
| Usgs Dyfi Mmi | 3.6 |
| Usgs Dyfi Sig | 415 |
| Usgs Dyfi Tsunami | false |
| Usgs Dyfi Place | 20 km E of Castle Rock, Washington |
Safety Information
If you feel shaking: Drop, Cover, and Hold On. Move away from windows, heavy objects, and exterior walls. After shaking stops, check for injuries and structural damage. Be prepared for aftershocks, which can occur minutes to months after the mainshock. Follow instructions from local emergency management authorities.
Series begins 8 March 2026. Comparisons refer to that period only. Collection gap: 14-26 August 2026.
This data is aggregated algorithmically from scientific sources. Not a replacement for official emergency warnings.
Want to know when something happens near Longview?
Calamity.live data shows a earthquake event with CalamityScore 0/100, near Longview (United States), based on data from usgs_canada. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.