Right now
The most recent data we hold from USGS arrived 20 hours ago, and this point is in it.
Nothing else has been detected within 20 km in the last 24 hours.
Reported by USGS yesterday.
It is the only one we have recorded within 20 km of this point since 18 September 2026.
What the source measured
USGS reported: 5 km NW of Black Eagle, Montana
USGS recorded magnitude 3.6 at a depth of 28 km.
The seismic region given by the source is 5 km NW of Black Eagle, Montana.
Urban PEI: 33,253 within a heuristic 15 km radius; not unique people.
How we know
One source: USGS. Not yet confirmed by a second, independent source.
Our own score for this event is 12 out of 100.
This is our versioned heuristic index, not source severity or a calibrated probability. Urban PEI does not count unique people.
Computed under scoring rules v5. Rows carrying other versions were judged by different rules and are not directly comparable.
Event Data
| Type | Earthquakes |
| Severity | Low |
| Calamity Score (ours) | 12 / 100 |
| Legacy data-support index | 0.70/1 |
| Coordinates | 47.5572, -111.3244 |
| Nearest City | Great Falls (7 km) |
| Urban exposure index (PEI) | 33.3K within 15 km |
| Impact Tier | minor |
| Timestamp | 2026-09-18T13:40:42.979Z |
| Source | https://earthquake.usgs.gov/earthquakes/eventpage/us7000tiax |
Physical priority index · v5. Heuristic priority, not calibrated probability, predictive accuracy or damage. The legacy data-support index combines assigned source support and field availability. Urban PEI is distance-weighted and does not count unique people; zero does not establish that nobody is present. Model cards.
Source and revision timeline
Source: usgs_canada. Occurrence: 2026-09-18T13:40:42.979Z.
First archived: 2026-09-18T13:53:56.829Z. Material modification: not recorded.
Retained revisions are prospective; earlier versions may be unavailable. No revision entry does not prove that a record never changed.
2026-09-19T01:35:45.460Z · data_change
Index 12 → 12; severity low → low; version 5 → 5.
2026-09-19T01:25:05.513Z · data_change
Index 12 → 12; severity low → low; version 5 → 5.
2026-09-19T01:14:23.968Z · data_change
Index 12 → 12; severity low → low; version 5 → 5.
2026-09-19T00:58:23.786Z · data_change
Index 12 → 12; severity low → low; version 5 → 5.
2026-09-19T00:42:20.451Z · data_change
Index 12 → 12; severity low → low; version 5 → 5.
2026-09-19T00:26:16.807Z · data_change
Index 12 → 12; severity low → low; version 5 → 5.
2026-09-19T00:15:25.587Z · data_change
Index 12 → 12; severity low → low; version 5 → 5.
2026-09-18T23:32:03.459Z · data_change
Index 12 → 12; severity low → low; version 5 → 5.
Score Breakdown
Technical Details
| Mag | 3.6 |
| Depth | 27.73 |
| Sig | 258 |
| Tsunami | false |
| Region | 5 km NW of Black Eagle, Montana |
| Usgs Mag | 3.6 |
| Usgs Depth | 27.73 |
| Usgs Tsunami | false |
| Usgs Felt | 171 |
| Usgs Mmi | 3.32 |
| Usgs Sig | 258 |
| Usgs Dyfi Mag | 3.6 |
| Usgs Dyfi Depth | 27.73 |
| Usgs Dyfi Felt | 170 |
| Usgs Dyfi Cdi | 3.4 |
| Usgs Dyfi CdiDescription | Weak |
| Usgs Dyfi Mmi | 3.32 |
| Usgs Dyfi Sig | 257 |
| Usgs Dyfi Tsunami | false |
| Usgs Dyfi Place | 5 km NW of Black Eagle, Montana |
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.
Review the area, threshold and delivery channel in your account.
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