PlainQuake

Interactive tool

Earthquake Risk Calculator

Select a US state to assess its earthquake risk from 20 years of USGS ComCat data, historical counts, maximum magnitude, yearly frequency, and a computed risk level.

Alaska

Very High Risk

Alaska has extremely high seismic activity with 8,929 recorded M4+ events and 111 significant (M6+) earthquakes. Active fault systems pose ongoing risk.

Total Earthquakes

8,929

Max Magnitude

7.9

Significant (M6+)

111

Avg Magnitude

4.5

Strongest Recorded Earthquakes

Magnitude Location
M7.9 261 km SE of Chiniak, Alaska
M7.9 Rat Islands, Aleutian Islands, Alaska
M7.9 77 km WSW of Adak, Alaska
M7.9 200 km WSW of Yakutat, Alaska
M7.9 93 km NW of Attu Station, Alaska

Earthquake Frequency by Year

Year Events Max Mag
2026 3 6.4
2025 3 6.2
2024 5 6.3
2023 2 6.4
2022 5 6.8
2021 5 6.9
2020 5 6.4
2019 4 6.4
2018 7 7.9
2017 6 6.8
2016 4 7.1
2015 5 6.9
2014 9 7.9
2013 6 7.5
2012 5 6.4
2011 4 7.3
2010 7 6.7
2009 3 6.5
2008 7 6.6
2007 10 7.2
2006 5 6.6
2005 2 6.8
2004 3 6.8
2003 7 7.8
2002 4 6.6
2001 6 6.9
2000 3 6.5
1999 7 7.0
1998 3 6.3
1997 6 6.7
1996 6 7.9
1995 5 6.5
1994 1 6.2
1993 6 6.9
1992 11 6.9
1991 5 7.0
1990 6 7.1
1989 9 7.0
1988 7 7.8
1987 11 7.9
1986 10 6.8
1985 10 6.6
1983 4 6.6
1982 3 6.4
1981 1 7.0
1980 2 6.9
1979 6 7.1
1978 2 6.7
1977 7 6.7
1975 4 7.6
1974 5 6.5
1973 5 6.7
1972 5 7.6
1971 7 7.0
1970 9 7.1
1969 3 6.9
1968 8 6.6
1967 4 6.8
1966 6 6.9
1965 20 7.8
1964 29 6.9
1963 5 6.6
1962 7 6.5
1961 9 6.5
1960 7 6.8
1959 4 6.3
1958 12 7.8
1957 57 7.2
1956 9 6.5
1955 12 6.8
1954 4 6.8
1953 4 7.0
1952 6 6.5
1951 3 6.9
1950 6 6.4
1949 2 6.6
1948 9 7.1
1947 3 7.1
1946 12 6.8
1945 6 6.2
1944 3 6.6
1943 2 6.9
1942 7 6.3
1941 5 6.5
1940 16 7.0
1939 6 7.2
1938 5 6.9
1937 3 7.1
1936 3 6.8
1935 3 6.9
1934 6 6.8
1933 12 6.8
1932 8 6.8
1931 4 6.3
1930 7 6.7
1929 14 7.9
1928 1 7.0
1927 10 7.2
1926 7 6.9
1925 3 6.6
1924 4 6.4
1923 5 7.0
1922 2 6.8
1921 1 6.2
1920 3 6.3
1919 2 6.2
1918 4 6.2
1917 7 7.4
1916 5 7.4
1915 2 6.4
1914 1 6.5
1913 4 6.9
1912 7 7.2
1911 4 6.9
1910 2 7.0
1909 2 7.0
1908 2 6.7
1907 3 7.4
1906 4 7.0
1905 4 7.6
1904 1 7.3
1903 2 7.0
1902 1 7.0
1901 2 7.1
1900 1 7.9

Events in 125 of 21 monitoring years (595% frequency).

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Frequently Asked Questions

How is earthquake risk level determined? ▼
Risk levels (Low, Moderate, High, Very High) are determined by combining total earthquake count, maximum recorded magnitude, number of significant events (M6+), and the frequency of seismic activity across the 2005-2025 monitoring period.
What data does this calculator use? ▼
The calculator uses the USGS Comprehensive Earthquake Catalog (ComCat), covering earthquakes of magnitude 4.0 and above worldwide since 2005, over 310,000 events. US state figures are aggregated from that same global M4+ record.
Does low risk mean no earthquake danger? ▼
No. Low risk means fewer recorded events in the USGS dataset, but earthquakes can occur in any state. Areas with low historical activity can still experience damaging events. Always follow FEMA and USGS preparedness guidelines regardless of risk level.
What counts as a significant earthquake? ▼
For this calculator, significant earthquakes are those with magnitude 6.0 or greater. These events can cause substantial damage to buildings and infrastructure, especially in areas without seismic building codes.
How often is the data updated? ▼
The database covers USGS ComCat records from 2005 through 2025. Historical data is stable; new events are added periodically.

Data: USGS Comprehensive Earthquake Catalog (ComCat), magnitude 4.0+ worldwide since 2005. Risk levels are computed assessments and should not replace official USGS or FEMA hazard maps.