U.S. state profile · USGS ComCat
Earthquakes in Alaska
Alaska has catalogued 8,996 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 428 M4+ events a year alongside 756 significant M6+ earthquakes since 1900. Below: the full M6+ event history, magnitude and depth profile, and yearly trend.
- 8,996
- M4+ events (since 2005)
- 756
- Major M6+ (since 1900)
- M9.2
- Strongest
- ~428
- M4+ per year
The verdict
Alaska is one of the world's most seismically active places, with 8,996 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 tops the tracked set; the next step down is Northern Mariana Islands at 3,345 M4+ events.
USGS ComCat event tape
Event tape AK · Alaska M4+ · 1st/39
Alaska · 8,996 M4+ · max M9.2 · 756 M6+
- M6 8,996
- DEPTH 1st/39
- PHOTO M9.2
- BUSY 756
- SHAL near Northern Mariana Islands
- PCT 95% 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 Alaska
USGS recorded Modified Mercalli Intensity (MMI) for 157 events in this catalogued record; their average observed intensity was MMI 5.8. These are only events with an observation, not an estimate of future shaking or a safety rating.
- MMI observations
- 157
- Average observed MMI
- 5.8
- PAGER alerts / tsunami flags
- 72 / 64
Source: USGS Comprehensive Earthquake Catalog (ComCat) GeoJSON impact fields. Missing MMI, alert, and tsunami values remain unreported rather than being treated as zero.
Where Alaska sits in the catalog
Rank 1st of 39 tracked U.S. states and territories (97th percentile by M4+ count since 2005). Alaska tops the tracked set; the next step down is Northern Mariana Islands at 3,345 M4+ events.
- Northern Mariana Islands - next less active (3,345 M4+)
Alaska's M4+ count vs. every tracked state
Total catalogued M4+ events since 2005, USGS ComCat
8,996 Top 3% higher than 97% 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
Major (M6+) earthquakes in Alaska by year
Count of significant (magnitude 6.0+) events catalogued each year
- 2015
2015: 5 major (M6+) events
5
- 2016
2016: 4 major (M6+) events
4
- 2017
2017: 6 major (M6+) events
6
- 2018
2018: 7 major (M6+) events
7
- 2019
2019: 4 major (M6+) events
4
- 2020
2020: 7 major (M6+) events
7
- 2021
2021: 6 major (M6+) events
6
- 2022
2022: 5 major (M6+) events
5
- 2023
2023: 3 major (M6+) events
3
- 2024
2024: 5 major (M6+) events
5
- 2025
2025: 4 major (M6+) events
4
- 2026
2026: 3 major (M6+) events
3
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.
How Alaska earthquake activity changed recently
| Year | M4+ events | YoY change | Global YoY |
|---|---|---|---|
| 2026 | 3 | -25.0% | -43.9% |
| 2025 | 4 | -20.0% | +29.3% |
| 2024 | 5 | +66.7% | -12.6% |
| 2023 | 3 | -40.0% | +3.0% |
| 2022 | 5 | -16.7% | -8.9% |
Alaska's M4+ activity rose faster than the global average in 2026: -25.0% locally vs -43.9% globally, a 18.9-point gap.
Source: USGS Comprehensive Earthquake Catalog (ComCat). M4+ = magnitude 4.0 or greater. YoY = year-on-year change. Global column uses the worldwide total from the same catalog.
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.
Shallow (<70 km)
716
95% of events
Intermediate (70–300 km)
40
5.3% 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. Alaska's latest M4+ catalog entry is dated Aug 26, 2026. For the national PGA design-basis tiers, see the seismic risk maps guide or the USGS National Seismic Hazard Model.
Strongest earthquakes in Alaska
The 10 most powerful events on record (USGS, since 1900).
| Mag | Location | Depth | Date |
|---|---|---|---|
| 9.2 | The 1964 Prince William Sound, Alaska Earthquake | 25.0 km | Mar 28, 1964 |
| 8.6 | 1957 Atka, Alaska Earthquake | 25.0 km | Mar 9, 1957 |
| 8.6 | The 1946 Unimak Island, Alaska Earthquake | 15.0 km | Apr 1, 1946 |
| 8.2 | 1938 Semidi Islands, Alaska Earthquake | 35.0 km | Nov 10, 1938 |
| 8.2 | 2021 Chignik, Alaska Earthquake | 35.0 km | Jul 29, 2021 |
| 8.0 | 1986 Atka, Alaska Earthquake | 33.0 km | May 7, 1986 |
| 7.9 | 261 km SE of Chiniak, Alaska | 14.1 km | Jan 23, 2018 |
| 7.9 | Rat Islands, Aleutian Islands, Alaska | 109.0 km | Jun 23, 2014 |
| 7.9 | 2002 Denali Fault, Alaska Earthquake | 4.2 km | Nov 3, 2002 |
| 7.9 | 77 km WSW of Adak, Alaska | 33.0 km | Jun 10, 1996 |
Significant earthquake record (756 events)
Every catalogued magnitude-6.0-and-above earthquake in Alaska since 1900, most recent first.
| Mag | Location | Depth | Date |
|---|---|---|---|
| 6.1 | Rat Islands, Aleutian Islands, Alaska | 16.3 km | May 9, 2026 |
| 6.4 | 223 km ESE of Attu Station, Alaska | 10.0 km | Mar 4, 2026 |
| 6.0 | 96 km SW of Nikolski, Alaska | 14.0 km | Feb 23, 2026 |
| 6.0 | 12 km WNW of Susitna, Alaska | 69.4 km | Nov 27, 2025 |
| 6.2 | 91 km SSE of Sand Point, Alaska | 40.0 km | Jul 20, 2025 |
| 7.3 | 2025 Sand Point, Alaska Earthquake | 38.0 km | Jul 16, 2025 |
| 6.2 | 88 km SSE of Adak, Alaska | 17.0 km | Mar 21, 2025 |
| 6.1 | 126 km SSW of Adak, Alaska | 10.0 km | Dec 9, 2024 |
| 6.3 | 104 km SSW of Adak, Alaska | 19.0 km | Dec 9, 2024 |
| 6.3 | 108 km SSW of Adak, Alaska | 18.0 km | Dec 8, 2024 |
| 6.0 | 168 km SW of Nikolski, Alaska | 41.0 km | Jul 19, 2024 |
| 6.0 | 169 km SW of Nikolski, Alaska | 28.0 km | May 19, 2024 |
| 6.1 | 116 km SE of Adak, Alaska | 20.0 km | Dec 21, 2023 |
| 6.4 | 78 km NNW of Adak, Alaska | 174.0 km | Oct 16, 2023 |
| 7.2 | 2023 Sand Point, Alaska Earthquake | 25.0 km | Jul 16, 2023 |
| 6.3 | Rat Islands, Aleutian Islands, Alaska | 73.0 km | Dec 14, 2022 |
| 6.3 | Rat Islands, Aleutian Islands, Alaska | 105.0 km | Jun 4, 2022 |
| 6.2 | 71 km S of Unalaska, Alaska | 29.0 km | Jan 22, 2022 |
| 6.6 | 53 km SE of Nikolski, Alaska | 19.0 km | Jan 11, 2022 |
| 6.8 | 100 km SE of Nikolski, Alaska | 20.0 km | Jan 11, 2022 |
| 6.9 | 112 km E of Chignik, Alaska | 51.6 km | Oct 11, 2021 |
| 6.1 | 187 km WSW of Adak, Alaska | 18.0 km | Sep 24, 2021 |
| 6.9 | 125 km SE of Perryville, Alaska | 20.7 km | Aug 14, 2021 |
| 8.2 | 2021 Chignik, Alaska Earthquake | 35.0 km | Jul 29, 2021 |
| 6.1 | 73 km N of Chickaloon, Alaska | 44.0 km | May 31, 2021 |
| 6.1 | 230 km WSW of Adak, Alaska | 21.0 km | Jan 3, 2021 |
| 6.4 | 46 km ESE of Nikolski, Alaska | 23.0 km | Dec 1, 2020 |
| 7.6 | 2020 Sand Point, Alaska Earthquake | 28.4 km | Oct 19, 2020 |
| 6.1 | 75 km SW of Sand Point, Alaska | 35.1 km | Jul 28, 2020 |
| 6.1 | 101 km ESE of Sand Point, Alaska | 16.5 km | Jul 22, 2020 |
| 7.8 | 2020 Perryville, Alaska Earthquake | 28.0 km | Jul 22, 2020 |
| 6.1 | 240 km WSW of Adak, Alaska | 17.0 km | Jan 26, 2020 |
| 6.2 | 84 km W of Adak, Alaska | 10.0 km | Jan 23, 2020 |
| 6.0 | 127 km SW of Adak, Alaska | 28.0 km | Dec 2, 2019 |
| 6.3 | 95 km SE of Adak, Alaska | 20.0 km | Nov 24, 2019 |
| 6.0 | 127 km WSW of Adak, Alaska | 30.0 km | May 23, 2019 |
| 6.4 | Rat Islands, Aleutian Islands, Alaska | 8.0 km | Apr 2, 2019 |
| 6.0 | 87 km SE of King Cove, Alaska | 31.0 km | Dec 31, 2018 |
| 7.1 | 1 km SE of Point MacKenzie, Alaska | 46.7 km | Nov 30, 2018 |
| 6.3 | 97 km SW of Adak, Alaska | 20.0 km | Aug 23, 2018 |
| 6.5 | 108 km WSW of Adak, Alaska | 33.9 km | Aug 15, 2018 |
| 6.0 | 73 km SSW of Kaktovik, Alaska | 16.2 km | Aug 12, 2018 |
| 6.4 | 89 km SW of Kaktovik, Alaska | 15.8 km | Aug 12, 2018 |
| 7.9 | 261 km SE of Chiniak, Alaska | 14.1 km | Jan 23, 2018 |
| 6.5 | 247 km ESE of Attu Station, Alaska | 119.0 km | Oct 8, 2017 |
| 6.8 | 200 km NW of Attu Station, Alaska | 5.0 km | Jun 2, 2017 |
| 6.2 | 135 km W of Adak, Alaska | 13.0 km | May 8, 2017 |
| 6.3 | 48 km NW of Mosquito Lake, Alaska | 2.5 km | May 1, 2017 |
| 6.2 | 47 km NW of Mosquito Lake, Alaska | 10.0 km | May 1, 2017 |
| 6.2 | 63 km W of Attu Station, Alaska | 20.0 km | Mar 27, 2017 |
| 6.2 | 42 km E of Port Heiden, Alaska | 11.4 km | Apr 2, 2016 |
| 6.0 | 75 km S of Atka, Alaska | 17.0 km | Mar 19, 2016 |
| 6.3 | 72 km SSE of Atka, Alaska | 19.0 km | Mar 12, 2016 |
| 7.1 | 47 km ESE of Pedro Bay, Alaska | 125.6 km | Jan 24, 2016 |
| 6.5 | 99 km SE of Atka, Alaska | 15.0 km | Nov 9, 2015 |
| 6.0 | 104 km SSW of Nikolski, Alaska | 20.0 km | Sep 10, 2015 |
| 6.4 | 52 km ENE of Pedro Bay, Alaska | 119.3 km | Jul 29, 2015 |
| 6.9 | Fox Islands, Aleutian Islands, Alaska | 29.0 km | Jul 27, 2015 |
| 6.8 | 117 km SSE of Ugashik, Alaska | 72.6 km | May 29, 2015 |
| 6.2 | 22 km WSW of Skwentna, Alaska | 108.9 km | Sep 25, 2014 |
| 6.0 | 40 km WNW of Elfin Cove, Alaska | 10.0 km | Jul 25, 2014 |
| 6.0 | 90 km NNW of Yakutat, Alaska | 10.0 km | Jul 17, 2014 |
| 6.3 | 248 km ESE of Attu Station, Alaska | 4.0 km | Jun 24, 2014 |
| 6.0 | Rat Islands, Aleutian Islands, Alaska | 106.6 km | Jun 23, 2014 |
| 6.0 | Rat Islands, Aleutian Islands, Alaska | 101.9 km | Jun 23, 2014 |
| 6.0 | Rat Islands, Aleutian Islands, Alaska | 102.8 km | Jun 23, 2014 |
| 7.9 | Rat Islands, Aleutian Islands, Alaska | 109.0 km | Jun 23, 2014 |
| 6.1 | 210 km WNW of Nikolski, Alaska | 265.0 km | Feb 26, 2014 |
| 6.1 | 77 km SSW of Atka, Alaska | 24.0 km | Sep 15, 2013 |
| 6.0 | 82 km SSW of Atka, Alaska | 17.0 km | Sep 4, 2013 |
| 6.5 | 81 km SSW of Atka, Alaska | 20.0 km | Sep 4, 2013 |
| 6.0 | 118 km SSW of Atka, Alaska | 18.0 km | Aug 31, 2013 |
| 7.0 | 101 km SW of Atka, Alaska | 29.0 km | Aug 30, 2013 |
| 7.5 | 110 km SW of Edna Bay, Alaska | 8.7 km | Jan 5, 2013 |
| 6.0 | 83 km SE of Attu Station, Alaska | 26.0 km | Dec 15, 2012 |
| 6.3 | 266 km SW of Yakutat, Alaska | 9.0 km | Nov 12, 2012 |
| 6.4 | 118 km WSW of Adak, Alaska | 16.0 km | Sep 26, 2012 |
| 6.2 | 102 km ESE of Nikolski, Alaska | 13.0 km | Aug 10, 2012 |
| 6.0 | 119 km WNW of Attu Station, Alaska | 14.0 km | Jun 19, 2012 |
| 6.0 | 32 km NNW of Attu Station, Alaska | 15.0 km | Sep 14, 2011 |
| 6.9 | 170 km E of Atka, Alaska | 32.0 km | Sep 2, 2011 |
| 6.1 | 72 km ESE of King Cove, Alaska | 36.0 km | Jul 16, 2011 |
| 7.3 | Fox Islands, Aleutian Islands, Alaska | 52.0 km | Jun 24, 2011 |
| 6.4 | 139 km WNW of Attu Station, Alaska | 18.0 km | Dec 23, 2010 |
| 6.0 | 120 km ESE of Adak, Alaska | 27.7 km | Oct 8, 2010 |
| 6.4 | 104 km ESE of Adak, Alaska | 19.0 km | Oct 8, 2010 |
| 6.5 | 70 km SE of Adak, Alaska | 23.5 km | Sep 3, 2010 |
| 6.4 | 148 km WSW of Adak, Alaska | 27.0 km | Aug 4, 2010 |
| 6.0 | 59 km WSW of Nikolski, Alaska | 10.0 km | Jul 18, 2010 |
| 6.7 | 66 km W of Nikolski, Alaska | 14.0 km | Jul 18, 2010 |
| 6.4 | 123 km ESE of Nikolski, Alaska | 14.0 km | Oct 13, 2009 |
| 6.5 | 127 km E of Nikolski, Alaska | 24.0 km | Oct 13, 2009 |
| 6.1 | Rat Islands, Aleutian Islands, Alaska | 22.0 km | Jul 6, 2009 |
| 6.1 | 72 km S of Atka, Alaska | 36.0 km | Nov 2, 2008 |
| 6.0 | 122 km SSE of Akhiok, Alaska | 20.0 km | May 25, 2008 |
| 6.3 | Rat Islands, Aleutian Islands, Alaska | 27.0 km | May 20, 2008 |
| 6.6 | 61 km W of Adak, Alaska | 14.0 km | May 2, 2008 |
| 6.6 | 174 km W of Adak, Alaska | 13.0 km | Apr 16, 2008 |
| 6.4 | 187 km W of Adak, Alaska | 11.0 km | Apr 15, 2008 |
| 6.2 | 146 km WNW of Adak, Alaska | 132.0 km | Mar 22, 2008 |
Showing the first 100 of 756 significant events.
Other states in this catalog sample
A Alaska-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 Alaska-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.