U.S. state profile · USGS ComCat
Earthquakes in Idaho
Idaho has catalogued 73 M4+ earthquakes since 2005 (ranked 11th of 39 U.S. states), with the strongest reaching magnitude M6.9.
Idaho ranks 11th of 39 U.S. states and territories by catalogued seismic activity - a moderately active state, averaging about 3 M4+ events a year alongside 2 significant M6+ earthquakes since 1900. Below: the full M6+ event history, magnitude and depth profile, and yearly trend.
- 73
- M4+ events (since 2005)
- 2
- Major M6+ (since 1900)
- M6.9
- Strongest
- ~3
- M4+ per year
The verdict
Idaho is moderately seismically active, above the global median, with 73 M4+ earthquakes logged since 2005 and 2 major M6+ events since 1900, the strongest reaching magnitude 6.9.
- 1983
- busiest year (1 major events)
- 11 km
- average recorded event depth
- 100%
- of events are shallow (<70 km, the most damaging kind)
Average catalogued magnitude is 4.3 - most events are moderate tremors felt but rarely damaging. On the M4+ activity ladder Oklahoma sits immediately above at 97 events and Georgia sits immediately below at 67.
ComCat magnitude tape
Event tape ID · Idaho M4+ · 11th/39
Idaho · 73 M4+ · max M6.9 · 2 M6+
- VS-PEER 73
- COMCAT 11th/39
- TAPE M6.9
- EPIC 2
- YOY near Oklahoma
- BAND 100% shallow
Stamps derive from this jurisdiction's USGS ComCat row (M4+ book, rank, peak magnitude, M6+ record, ladder neighbour, depth/peak year), not a hazard forecast. PlainQuake is informational only - not professional advice and not a substitute for official USGS guidance. See our disclaimer. Verify with USGS ComCat → · Read with methodology → · How earthquakes are measured → · Most active U.S. regions → · All state catalog rows → · States ranked →
Observed impact record
What ComCat observed after earthquakes in Idaho
USGS recorded Modified Mercalli Intensity (MMI) for 2 events in this catalogued record; their average observed intensity was MMI 8.4. These are only events with an observation, not an estimate of future shaking or a safety rating.
- MMI observations
- 2
- Average observed MMI
- 8.4
- PAGER alerts / tsunami flags
- 1 / 0
Source: USGS Comprehensive Earthquake Catalog (ComCat) GeoJSON impact fields. Missing MMI, alert, and tsunami values remain unreported rather than being treated as zero.
Where Idaho sits in the catalog
Rank 11th of 39 tracked U.S. states and territories (72th percentile by M4+ count since 2005). On the M4+ activity ladder Oklahoma sits immediately above at 97 events and Georgia sits immediately below at 67.
Idaho's M4+ count vs. every tracked state
Total catalogued M4+ events since 2005, USGS ComCat
73 Top 28% higher than 72% of 39 states
Each bar is a 100-wide band; taller bars hold more states. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.
Source USGS Comprehensive Earthquake Catalog (ComCat) · 2005-present
Magnitude distribution of major events
Breakdown of the 2 significant (M6+) earthquakes on record for Idaho.
M6.0–6.9
2
100.0%
Depth of major earthquakes
Hypocentral depth of the 2 M6+ events, shallow quakes shake the surface hardest. Average depth: 11 km.
Shallow (<70 km)
2
100% of events
Intermediate (70–300 km)
0
0.0% of events
Deep (>300 km)
0
0.0% of events
Seismic hazard context
Catalogued counts on this page are history, not a building-code hazard map. Idaho's latest M4+ catalog entry is dated Jun 8, 2025. For the national PGA design-basis tiers, see the seismic risk maps guide or the USGS National Seismic Hazard Model.
Strongest earthquakes in Idaho
The 2 most powerful events on record (USGS, since 1900).
| Mag | Location | Depth | Date |
|---|---|---|---|
| 6.9 | The 1983 Borah Peak Earthquake, Idaho | 10.0 km | Oct 28, 1983 |
| 6.5 | Stanley, Idaho | 12.1 km | Mar 31, 2020 |
Significant earthquake record (2 events)
Every catalogued magnitude-6.0-and-above earthquake in Idaho since 1900, most recent first.
| Mag | Location | Depth | Date |
|---|---|---|---|
| 6.5 | Stanley, Idaho | 12.1 km | Mar 31, 2020 |
| 6.9 | The 1983 Borah Peak Earthquake, Idaho | 10.0 km | Oct 28, 1983 |
Other states in this catalog sample
A Idaho-keyed shuffle of the full 38-state roster (not the six nearest by count), so adjacent quiet states do not share the same comparison set.
Peak-magnitude sample from the same roster
A second Idaho-keyed shuffle of states with a recorded max magnitude (independent order from the frequency sample above).
According to the US Geological Survey Earthquake Hazards Program, PlainQuake's figures are rendered directly from 317,293 recorded M4+ earthquakes and 14,444 significant M6+ events (USGS ComCat, 2005-present) -- no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 2026-08-26.