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.
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
How Idaho compares to its nearest peers
Idaho ranks in the 72th percentile for M4+ frequency among all 39 tracked U.S. states and territories. Plotted here against its 20 nearest-ranked peers by how OFTEN they shake (M4+ count) against how HARD the strongest one ever hit (max recorded magnitude).
Idaho vs. its 20 nearest-ranked peer states, USGS ComCat
Read the chart (all 21 values)
| State | M4+ events | Strongest magnitude |
|---|---|---|
| Alaska | 8,960 | M8.2 |
| Northern Mariana Islands | 3,328 | M7.7 |
| Guam | 2,456 | M6.8 |
| California | 883 | M7.2 |
| Puerto Rico | 296 | M6.4 |
| Oregon | 263 | M6.3 |
| U.S. Virgin Islands | 221 | M6.1 |
| Hawaii | 204 | M6.9 |
| Nevada | 170 | M6.5 |
| Oklahoma | 97 | M5.8 |
| Idaho (this page) | 73 | M6.5 |
| Georgia | 67 | M6.0 |
| Texas | 52 | M5.4 |
| New Mexico | 37 | M5.4 |
| Montana | 28 | M5.8 |
| Utah | 25 | M5.7 |
| American Samoa | 24 | M5.8 |
| Washington | 17 | M4.7 |
| Wyoming | 13 | M4.8 |
| Colorado | 12 | M5.3 |
| Kansas | 12 | M4.9 |
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
USGS seismic hazard context
PGA hazard tiers from the USGS National Seismic Hazard Map, the design-basis shaking used in building codes. These are the national distribution of hazard tiers across all US land area, not an Idaho-specific breakdown; Idaho's own position within these tiers depends on its local geology and fault proximity.
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 |
States with similar seismic activity
Comparable catalogued earthquake frequency to Idaho.
States with a similarly strong peak event
Closest all-time strongest catalogued magnitude to Idaho's M6.9.
Frequently asked questions
How many earthquakes hit Idaho? ▼
What was the largest earthquake in Idaho? ▼
How does Idaho rank for earthquakes? ▼
Where does this data come from? ▼
Understand the data
About this data
Every figure on this page is computed directly from the USGS Comprehensive Earthquake Catalog (ComCat), the public-domain record maintained by the USGS Earthquake Hazards Program. State assignment uses USGS place-name geocoding. Two series are combined: a worldwide catalog of magnitude-4.0-and-above events from 2005 onward - the period over which the global seismograph network reliably detects and locates earthquakes everywhere, and a historical series of significant magnitude-6.0-and-above events stretching back to 1900. Magnitudes use the moment-magnitude scale (Mw), the modern standard that supersedes the older Richter scale; because the scale is logarithmic, each whole step represents roughly thirty-two times more energy released. Depth is measured in kilometres from the surface, and shallow earthquakes generally produce stronger surface shaking than deep ones of the same magnitude. Counts reflect what instruments recorded, not every tremor that occurred, and recent events can be revised as seismologists refine the catalog.
Source: USGS ComCat, verify with USGS → · See our methodology for the full pipeline.
Disclaimer: PlainQuake is an informational reference for informational purposes only, not an emergency or early-warning service, and not professional engineering or safety advice. For official alerts and guidance, consult the USGS and your local emergency authorities. See our full disclaimer.
What Idaho's numbers mean
Idaho ranks 11th of 39 U.S. states and territories - a moderately active state.
- See Idaho's computed risk level alongside every other state, using the same USGS-derived methodology. Open the risk calculator
- 100% of Idaho's catalogued major earthquakes are shallow (under 70km) - shallow events generally produce stronger surface shaking than deep ones of the same magnitude. How depth affects shaking
- Compare Idaho against every other U.S. state by count and maximum magnitude. See the full state ranking
Figures reflect the USGS ComCat catalog (M4+ since 2005, M6+ significant events since 1900) - not a real-time hazard assessment. For official guidance, see the USGS Earthquake Hazards Program.
According to the US Geological Survey Earthquake Hazards Program, PlainQuake's figures are rendered directly from 315,341 recorded M4+ earthquakes and 14,428 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 2026-07-19.