PlainQuake

U.S. state profile · USGS ComCat

Earthquakes in Alaska

Alaska has catalogued 8,960 M4+ earthquakes since 2005 (ranked 1st of 39 U.S. states), with the strongest reaching magnitude M9.2.

Alaska ranks 1st of 39 U.S. states and territories by catalogued seismic activity - one of the most seismically active U.S. jurisdictions, averaging about 427 M4+ events a year alongside 756 significant M6+ earthquakes since 1900. Below: the full M6+ event history, magnitude and depth profile, and yearly trend.

8,960
M4+ events (since 2005)
756
Major M6+ (since 1900)
M9.2
Strongest
~427
M4+ per year

The verdict

Alaska is one of the world's most seismically active places, with 8,960 M4+ earthquakes logged since 2005 and 756 major M6+ events since 1900, the strongest reaching magnitude 9.2.

1957
busiest year (58 major events)
31 km
average recorded event depth
95%
of events are shallow (<70 km, the most damaging kind)

Average catalogued magnitude is 4.5 - most events are moderate tremors felt but rarely damaging.

Alaska's M4+ count vs. every tracked state

Total catalogued M4+ events since 2005, USGS ComCat

8,960 Top 3% higher than 97% of 39 states

0–100: 30 states (77%). Below this entry. 100–200: 1 states (3%). Below this entry. 200–300: 4 states (10%). Below this entry. 300–400: 0 states (0%). Below this entry. 400–500: 0 states (0%). Below this entry. 500–600: 0 states (0%). Below this entry. 600–700: 0 states (0%). Below this entry. 700–800: 0 states (0%). Below this entry. 800–900: 1 states (3%). Below this entry. 900–1,000: 0 states (0%). Below this entry. 1,000–1,100: 3 states (8%). This entry sits in this band. Alaska 0 1,000+ every tracked state, bucketed by value

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 Alaska compares to its nearest peers

Alaska ranks in the 97th percentile for M4+ frequency among all 39 tracked U.S. states and territories. Plotted here against its 10 nearest-ranked peers by how OFTEN they shake (M4+ count) against how HARD the strongest one ever hit (max recorded magnitude).

Alaska vs. its 10 nearest-ranked peer states, USGS ComCat

Alaska vs. its 10 nearest-ranked peer states, USGS ComCat 2×2 strategic matrix plotting 11 entities by M4+ events since 2005 (X) and Strongest recorded magnitude (Y), with a crosshair dividing the plot into four quadrants. Frequent and severeRare but severeFrequent, capped so farLower on both axes -2,00002,0004,0006,0008,00010,000 M5M6M7M8M9 M4+ events since 2005 Strongest recorded magnitude AlaskaNorthern Mariana IslandsGuamCaliforniaPuerto RicoOregonU.S. Virgin IslandsHawaiiNevadaOklahomaIdaho
Alaska vs. its 10 nearest-ranked peer states, USGS ComCat
Read the chart (all 11 values)
State M4+ events Strongest magnitude
Alaska (this page) 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 73 M6.5

Major (M6+) earthquakes in Alaska by year

Count of significant (magnitude 6.0+) events catalogued each year

Value

What this shows Alaska's most active year for major earthquakes was 1957 (58 M6+ events). Major-quake counts track the episodic release of tectonic stress, not a smooth trend.

Source USGS Comprehensive Earthquake Catalog (ComCat) As of 2026

Magnitude distribution of major events

Breakdown of the 756 significant (M6+) earthquakes on record for Alaska.

M8+

6

0.8%

M7.0–7.9

68

9.0%

M6.0–6.9

682

90.2%

Depth of major earthquakes

Hypocentral depth of the 756 M6+ events, shallow quakes shake the surface hardest. Average depth: 31 km.

AlaskaAlaska, Shallow (<70 km): 94.7%94.7%Alaska, Intermediate (70-300 km): 5.3%Shallow (<70 km)Intermediate (70-300 km)Deep (>300 km)
Depth distribution of Alaska's M6+ events, USGS ComCat

Shallow (<70 km)

716

95% of events

Intermediate (70–300 km)

40

5.3% 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 Alaska-specific breakdown; Alaska's own position within these tiers depends on its local geology and fault proximity.

HazardHazard, Low (PGA <0.05g): 35%35%Hazard, Moderate (0.05-0.15g): 32%32%Hazard, High (0.15-0.30g): 22%22%Hazard, Very High (>0.30g): 11%11%Low (PGA <0.05g)Moderate (0.05-0.15g)High (0.15-0.30g)Very High (>0.30g)
PGA hazard tiers (50-year design life) - National distribution, USGS National Seismic Hazard Map 2023 (USGS NSHM)

Strongest earthquakes in Alaska

The 10 most powerful events on record (USGS, since 1900).

Mag Location Depth
9.2 The 1964 Prince William Sound, Alaska Earthquake 25.0 km
8.6 1957 Atka, Alaska Earthquake 25.0 km
8.6 1946 Unimak Island, Alaska Earthquake 15.0 km
8.2 1938 Semidi Islands, Alaska Earthquake 35.0 km
8.2 2021 Chignik, Alaska Earthquake 35.0 km
8.0 1986 Atka, Alaska Earthquake 33.0 km
7.9 261 km SE of Chiniak, Alaska 14.1 km
7.9 Rat Islands, Aleutian Islands, Alaska 109.0 km
7.9 2002 Denali Fault, Alaska Earthquake 4.2 km
7.9 77 km WSW of Adak, Alaska 33.0 km

Significant earthquake record (756 events)

Every catalogued magnitude-6.0-and-above earthquake in Alaska since 1900, most recent first.

Mag Location Depth
6.1 Rat Islands, Aleutian Islands, Alaska 16.3 km
6.4 223 km ESE of Attu Station, Alaska 10.0 km
6.0 96 km SW of Nikolski, Alaska 14.0 km
6.0 12 km WNW of Susitna, Alaska 69.4 km
6.2 91 km SSE of Sand Point, Alaska 40.0 km
7.3 2025 Sand Point, Alaska Earthquake 38.0 km
6.2 88 km SSE of Adak, Alaska 17.0 km
6.1 126 km SSW of Adak, Alaska 10.0 km
6.3 104 km SSW of Adak, Alaska 19.0 km
6.3 108 km SSW of Adak, Alaska 18.0 km
6.0 168 km SW of Nikolski, Alaska 41.0 km
6.0 169 km SW of Nikolski, Alaska 28.0 km
6.1 116 km SE of Adak, Alaska 20.0 km
6.4 78 km NNW of Adak, Alaska 174.0 km
7.2 2023 Sand Point, Alaska Earthquake 25.0 km
6.3 Rat Islands, Aleutian Islands, Alaska 73.0 km
6.3 Rat Islands, Aleutian Islands, Alaska 105.0 km
6.2 71 km S of Unalaska, Alaska 29.0 km
6.6 53 km SE of Nikolski, Alaska 19.0 km
6.8 100 km SE of Nikolski, Alaska 20.0 km
6.9 112 km E of Chignik, Alaska 51.6 km
6.1 187 km WSW of Adak, Alaska 18.0 km
6.9 125 km SE of Perryville, Alaska 20.7 km
8.2 2021 Chignik, Alaska Earthquake 35.0 km
6.1 73 km N of Chickaloon, Alaska 44.0 km
6.1 230 km WSW of Adak, Alaska 21.0 km
6.4 46 km ESE of Nikolski, Alaska 23.0 km
7.6 2020 Sand Point, Alaska Earthquake 28.4 km
6.1 75 km SW of Sand Point, Alaska 35.1 km
6.1 101 km ESE of Sand Point, Alaska 16.5 km
7.8 2020 Perryville, Alaska Earthquake 28.0 km
6.1 240 km WSW of Adak, Alaska 17.0 km
6.2 84 km W of Adak, Alaska 10.0 km
6.0 127 km SW of Adak, Alaska 28.0 km
6.3 95 km SE of Adak, Alaska 20.0 km
6.0 127 km WSW of Adak, Alaska 30.0 km
6.4 Rat Islands, Aleutian Islands, Alaska 8.0 km
6.0 87 km SE of King Cove, Alaska 31.0 km
7.1 1 km SE of Point MacKenzie, Alaska 46.7 km
6.3 97 km SW of Adak, Alaska 20.0 km
6.5 108 km WSW of Adak, Alaska 33.9 km
6.0 73 km SSW of Kaktovik, Alaska 16.2 km
6.4 89 km SW of Kaktovik, Alaska 15.8 km
7.9 261 km SE of Chiniak, Alaska 14.1 km
6.5 247 km ESE of Attu Station, Alaska 119.0 km
6.8 200 km NW of Attu Station, Alaska 5.0 km
6.2 135 km W of Adak, Alaska 13.0 km
6.3 48 km NW of Mosquito Lake, Alaska 2.5 km
6.2 47 km NW of Mosquito Lake, Alaska 10.0 km
6.2 63 km W of Attu Station, Alaska 20.0 km
6.2 42 km E of Port Heiden, Alaska 11.4 km
6.0 75 km S of Atka, Alaska 17.0 km
6.3 72 km SSE of Atka, Alaska 19.0 km
7.1 47 km ESE of Pedro Bay, Alaska 125.6 km
6.5 99 km SE of Atka, Alaska 15.0 km
6.0 104 km SSW of Nikolski, Alaska 20.0 km
6.4 52 km ENE of Pedro Bay, Alaska 119.3 km
6.9 Fox Islands, Aleutian Islands, Alaska 29.0 km
6.8 117 km SSE of Ugashik, Alaska 72.6 km
6.2 22 km WSW of Skwentna, Alaska 108.9 km
6.0 40 km WNW of Elfin Cove, Alaska 10.0 km
6.0 90 km NNW of Yakutat, Alaska 10.0 km
6.3 248 km ESE of Attu Station, Alaska 4.0 km
6.0 Rat Islands, Aleutian Islands, Alaska 106.6 km
6.0 Rat Islands, Aleutian Islands, Alaska 101.9 km
6.0 Rat Islands, Aleutian Islands, Alaska 102.8 km
7.9 Rat Islands, Aleutian Islands, Alaska 109.0 km
6.1 210 km WNW of Nikolski, Alaska 265.0 km
6.1 77 km SSW of Atka, Alaska 24.0 km
6.0 82 km SSW of Atka, Alaska 17.0 km
6.5 81 km SSW of Atka, Alaska 20.0 km
6.0 118 km SSW of Atka, Alaska 18.0 km
7.0 101 km SW of Atka, Alaska 29.0 km
7.5 110 km SW of Edna Bay, Alaska 8.7 km
6.0 83 km SE of Attu Station, Alaska 26.0 km
6.3 266 km SW of Yakutat, Alaska 9.0 km
6.4 118 km WSW of Adak, Alaska 16.0 km
6.2 102 km ESE of Nikolski, Alaska 13.0 km
6.0 119 km WNW of Attu Station, Alaska 14.0 km
6.0 32 km NNW of Attu Station, Alaska 15.0 km
6.9 170 km E of Atka, Alaska 32.0 km
6.1 72 km ESE of King Cove, Alaska 36.0 km
7.3 Fox Islands, Aleutian Islands, Alaska 52.0 km
6.4 139 km WNW of Attu Station, Alaska 18.0 km
6.0 120 km ESE of Adak, Alaska 27.7 km
6.4 104 km ESE of Adak, Alaska 19.0 km
6.5 70 km SE of Adak, Alaska 23.5 km
6.4 148 km WSW of Adak, Alaska 27.0 km
6.0 59 km WSW of Nikolski, Alaska 10.0 km
6.7 66 km W of Nikolski, Alaska 14.0 km
6.4 123 km ESE of Nikolski, Alaska 14.0 km
6.5 127 km E of Nikolski, Alaska 24.0 km
6.1 Rat Islands, Aleutian Islands, Alaska 22.0 km
6.1 72 km S of Atka, Alaska 36.0 km
6.0 122 km SSE of Akhiok, Alaska 20.0 km
6.3 Rat Islands, Aleutian Islands, Alaska 27.0 km
6.6 61 km W of Adak, Alaska 14.0 km
6.6 174 km W of Adak, Alaska 13.0 km
6.4 187 km W of Adak, Alaska 11.0 km
6.2 146 km WNW of Adak, Alaska 132.0 km

Showing the first 100 of 756 significant events.

States with similar seismic activity

Comparable catalogued earthquake frequency to Alaska.

Northern Mariana Islands

3,328 M4+ events · strongest M7.7

M7.7

Guam

2,456 M4+ events · strongest M6.8

M6.8

California

883 M4+ events · strongest M7.2

M7.2

Puerto Rico

296 M4+ events · strongest M6.4

M6.4

Oregon

263 M4+ events · strongest M6.3

M6.3

U.S. Virgin Islands

221 M4+ events · strongest M6.1

M6.1

States with a similarly strong peak event

Closest all-time strongest catalogued magnitude to Alaska's M9.2.

Northern Mariana Islands

3,328 M4+ events

M7.7

California

883 M4+ events

M7.2

Hawaii

204 M4+ events

M6.9

Guam

2,456 M4+ events

M6.8

Idaho

73 M4+ events

M6.5

Nevada

170 M4+ events

M6.5

Frequently asked questions

How many earthquakes hit Alaska? ▼
The USGS catalog records 8,960 magnitude-4-and-above earthquakes in Alaska since 2005, about 427 per year, plus 756 major (M6+) events catalogued back to 1900.
What was the largest earthquake in Alaska? ▼
The strongest catalogued earthquake in Alaska measured magnitude 9.2. The average magnitude across the M4+ catalog is 4.5.
How does Alaska rank for earthquakes? ▼
Among U.S. states and territories, Alaska ranks 1st of 39 by catalogued M4+ activity - one of the most seismically active U.S. jurisdictions.
Where does this data come from? ▼
All figures come from the USGS Comprehensive Earthquake Catalog (ComCat). M4+ counts cover 2005 onward; the significant-event series covers M6+ back to 1900.

Understand the data

How earthquakes are measured

Magnitude scales, seismographs, and depth.

Most active U.S. regions

How the states rank for seismicity.

State rankings

Every state by M4+ activity.

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 Alaska's numbers mean

Alaska ranks 1st of 39 U.S. states and territories - one of the most seismically active U.S. jurisdictions.

  • See Alaska's computed risk level alongside every other state, using the same USGS-derived methodology. Open the risk calculator
  • 95% of Alaska'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 Alaska 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.