Largest Earthquakes in US History — and the Biggest in Every State (Mapped)

What is the largest earthquake in US history? The magnitude 9.2 Great Alaska earthquake of March 27, 1964, centred in Prince William Sound (03:36 UTC on March 28). It is the second-largest earthquake ever recorded anywhere, after Chile's M9.5 in 1960. Nine of the ten largest US earthquakes struck Alaska, so this page also ranks the largest outside Alaska, in California and in each of the 50 states, all from the USGS Comprehensive Catalog (ComCat).

The 10 Largest Earthquakes in US History

How we rank. Magnitude is ComCat's preferred magnitude for each event. An earthquake counts as "US" if its epicentre is inside a state, or offshore within 370 km (200 nautical miles) of a state and closer to the US than to any other country. Puerto Rico is listed separately; other territories are not ranked. Ties share a rank. Dates are UTC.

Source: USGS ComCat (earthquake.usgs.gov), queried 2026-10-09.

Three of the ten predate seismographs: Cascadia and the two Yakutat Bay shocks. Cascadia (1700) is known from geology along the Northwest coast and from an "orphan" tsunami recorded in Japan with no felt earthquake; the USGS study of that tsunami (Professional Paper 1707) dates the earthquake to the evening of January 26, 1700, local time. ComCat lists it at M9.0, within PP1707's estimate of M8.7–9.2; the Yakutat Bay magnitudes of September 1899 are also estimates. The newest entry is the 2021 Chignik earthquake (M8.2), the largest US earthquake since 1965.

The Largest Earthquakes Outside Alaska

Same rule as above, excluding events whose nearest state is Alaska. Source: USGS ComCat.

Just below the cut are the 1838 San Andreas Fault and 1872 Owens Valley earthquakes (both M7.4), then the 1992 Landers earthquake and the January 1812 New Madrid shock (both M7.3).

New Madrid, 1811–12. Three great shocks hit the central Mississippi Valley: M7.5 on December 16, 1811, M7.3 on January 23 and M7.5 on February 7, 1812 (ComCat). ComCat places them in northeastern Arkansas, north of New Madrid, Missouri, and western Tennessee; USGS's summary places them in northeast Arkansas, Missouri, and along the Reelfoot fault in Missouri and Tennessee, and we follow USGS for states. These are estimates from historical accounts, and catalogs differ: NOAA's NCEI database locates the February shock at New Madrid, Missouri, lists Charleston, 1886 at M7.3 (ComCat 7.03), and puts the December 8, 1812 California shock at M6.9 (San Juan Capistrano), not M7.5. Treat every pre-1900 magnitude here as an estimate.

The Biggest Earthquakes in California History

What is the biggest earthquake in California history? The 1857 Fort Tejon earthquake, M7.9 (7.93 in ComCat), which ruptured the San Andreas Fault on the morning of January 9, 1857. The 1906 San Francisco earthquake is level at M7.9. Ranking: epicentre in California, or offshore within 100 km with California the nearest state.

Source: USGS ComCat, queried 2026-10-09.

The most destructive modern California earthquakes are not on the list. Loma Prieta (M6.9, 5:04 pm local on October 17, 1989) caused 63 deaths and an estimated $6 billion in property damage (USGS). Northridge (M6.7, 4:30 am local on January 17, 1994) killed 57 people according to NOAA's NCEI database, and is the costliest for insurers (below). The largest within the list's footprint since 1952 is Landers (M7.3, 1992). The most recent M7s are Ridgecrest (M7.1, July 2019) and the December 2024 offshore Cape Mendocino earthquake (M7.0). Further offshore, a 1922 M7.41 event lay 121 km west of Big Lagoon, just beyond the 100 km rule.

The Largest Earthquake in Every State

Rule: the largest ComCat event whose epicentre lies inside the state boundary (US Census cartographic boundaries). Where a larger event lies just offshore, nearest to that state and within 100 km, we show it and give the largest on land in the notes. Ties are shown. "Pre-1900 estimate" marks events before 1900; "felt-report estimate" marks later magnitudes derived from felt area or intensity rather than seismographs. For the 1811–12 New Madrid shocks we follow USGS's own state attribution, because ComCat's rounded epicentres sit on state lines.

Source: USGS ComCat (FDSN event service), queried 2026-10-09; state boundaries US Census Bureau cb_2023.

Every state has a catalogued earthquake, from Rhode Island's M3.5 to Alaska's M9.2. In 28 states the record, or one half of a tied record, predates 1900 or rests on felt reports. Several modern records are recent: Oklahoma's M5.8 Pawnee earthquake (2016), Delaware's M4.1 (2017) and Louisiana's M4.9 in Red River Parish on March 5, 2026, which displaced a 1930 M4.2.

Map: Epicentres and ShakeMap Shaking

The map plots every ranked earthquake above, Puerto Rico included; six of California's top 10 appear only when you switch that list on. Shaded areas, on at load, are USGS ShakeMap intensity (Modified Mercalli, MMI IV+) for every mapped quake with a ShakeMap: 44 of the 92 dots, plus Northridge, Loma Prieta and 2002 Denali Fault (shaded, no dot). Stronger shaking shows on top. Most quakes before 1970 have none. Black lines are ShakeMap MMI contours (V to VIII) for 1964 Alaska, Northridge and Ridgecrest. Click any dot for its magnitude, date and ComCat link.

Open map full screen ↗

Explore the map: switch on more layers with the layers icon at the bottom right of the map: California's top 10; fault traces from USGS's Quaternary fault database; tsunami observations (NCEI) for 1964 Alaska and the other top-10 Alaska quakes, and the 1700 Cascadia tsunami's records in Japan; aftershocks in the first 7 days for 9 quakes; felt reports for 28; and USGS slip and ground-failure models.

What the map can show, by era. Every quake has a ComCat epicentre. ShakeMaps cover modern quakes and some big historical ones, reconstructed long after the event (1886, 1906, 1964). Their intensity blends recordings, felt reports and models (MODELED); measured magnitudes OBSERVED, pre-1900 and felt-report ones estimates. Tsunami records span 1700–2021, felt reports are mostly from 1999 on and slip models from 2002; the popups add PAGER (2011 on).

In the DisasterAWARE Archive Since 2014

The DisasterAWARE historical hazard archive holds 73,969 earthquake records (queried October 9, 2026), and 12,820 of them carry a USGS ShakeMap block with peak intensity, peak acceleration contours, the USGS PAGER alert level and, where NOAA's NCEI has them, deaths and damage. One earthquake can have several records; merged by earthquake, it holds all 12 of the M7+ US earthquakes in ComCat since 2014:

Source: DisasterAWARE Historical Hazards API, queried 2026-10-09; magnitudes and peak MMI from each record's USGS ShakeMap block; PAGER level from the record's impact block. Alert = the DisasterAWARE alert level issued (ALERT); MMI is MODELED.

Ranked by peak ShakeMap intensity on land instead of magnitude, the strongest shaking among M5+ US earthquakes in the archive since 2014 came from Ridgecrest (M7.1, MMI 8.7), Hubbard Glacier (M7.0, 8.4), the Ridgecrest M6.4 foreshock (8.4), the 2018 Kīlauea M6.9 (8.3), South Napa 2014 (M6.0, 8.2), Stanley, Idaho, 2020 (M6.5, 8.2), the 2014 Rat Islands M7.9 (8.1), Monte Cristo Range, Nevada, 2020 (M6.5, 8.1), offshore Cape Mendocino 2024 (M7.0, 8.1) and Ferndale 2022 (M6.4, 7.9). A shallow M6 under a city can shake harder than an M8 far offshore: the M7.9 in the Gulf of Alaska in 2018 peaked at MMI 4.3.

Our record geocodes the 2025 Hubbard Glacier earthquake to Yukon; USGS places the epicentre in Alaska, a few kilometres from the border, and we follow USGS.

For Insurers and Reinsurers: Magnitude Is Not Loss

The costliest US earthquakes are not the largest. In the Insurance Information Institute's table (from Aon data, as of January 2025), Northridge leads at $15.3 billion insured when it occurred, $33.0 billion in 2024 dollars. Next come 1906 San Francisco ($235 million then, $8.5 billion in 2024 dollars) and Loma Prieta ($960 million, $2.4 billion). Nisqually 2001 ($315 million), South Napa 2014 ($200 million) and Anchorage 2018 ($150 million) also make the top ten. None of the Alaska megathrust earthquakes in our top ten does. Economic losses run far higher than insured ones: USGS put Northridge's losses at about $20 billion, and NCEI's database records $40 billion.

What drives loss is shaking intensity over exposure: Northridge's M6.7 struck beneath the San Fernando Valley, while Chignik's M8.2 struck off a thinly populated coast and peaked on land at ShakeMap MMI 7.4. That is why earthquake probable maximum loss (PML) is built from footprints, not magnitudes: historical or scenario ShakeMaps are laid over insured locations, intensity is turned into damage, and losses are ranked by return period. The same footprints can anchor parametric covers that pay on site intensity.

NOAA's billion-dollar disasters database covers only weather and climate, so earthquake loss history has to come from insurer, USGS and NCEI sources. DisasterAWARE's earthquake data attaches the USGS ShakeMap summary, PGA contours and NCEI impact fields to each enhanced earthquake record, the event-level detail needed to back-test a PML or a parametric trigger. Historical Event Intelligence licenses the archive across every hazard, and a free Chile 2015 earthquake sample shows the record format with no signup.

Frequently Asked Questions

What is the largest earthquake ever recorded in the United States? The M9.2 Great Alaska earthquake of March 27, 1964 (local time) in Prince William Sound, the second-largest ever recorded worldwide. NOAA's NCEI database records 139 deaths including secondary effects such as the tsunamis, 15 of them attributed to the earthquake itself.

What are the top 10 earthquakes in US history? By ComCat magnitude: 1964 Alaska (M9.2), 1700 Cascadia (M9.0), 1965 Rat Islands (M8.7), 1946 Unimak Island and 1957 Atka (M8.6), 1906 Rat Islands (M8.3), 1938 Semidi Islands (M8.23), 2021 Chignik (M8.2), and the two Yakutat Bay shocks of 1899 (M8.16). Every one is in Alaska except Cascadia, off Oregon, Washington and northern California.

What is the biggest earthquake in California history? The 1857 Fort Tejon earthquake on the San Andreas Fault, M7.9 (7.93 in ComCat), just ahead of the 1906 San Francisco earthquake at M7.9. The largest since 1952 is Landers (M7.3, 1992).

What was the worst earthquake in US history? By deaths, the 1906 San Francisco earthquake and fire: NOAA's NCEI database records 700 deaths, more than any other US earthquake it lists, and later research cited by USGS puts the toll at more than 3,000. By insured loss, Northridge (1994): $15.3 billion at the time, $33.0 billion in 2024 dollars (Insurance Information Institute, from Aon).

Which states have had a magnitude 7 earthquake? On land or just offshore, by ComCat: Alaska, California, Hawaii, Arkansas (New Madrid, December 1811), Missouri and Tennessee (New Madrid, 1812), Montana, Nevada, South Carolina (Charleston, 1886, M7.03), and Oregon (Cascadia, offshore). Puerto Rico has had two offshore.

Related Reading

• Biggest Earthquakes of 2026 So Far
• Earthquake Data: ShakeMap, PGA Contours and Impact
• Earthquake Risk in Los Angeles, CA
• Earthquake Risk in San Francisco, CA
• Earthquake Risk in Seattle, WA
• Earthquake Risk in Memphis, TN
• Secondary Perils and Insurance Risk

Sources: USGS ComCat (FDSN event service) and USGS ShakeMap / ShakeMap Atlas products, queried 2026-10-09; USGS Professional Paper 1707, The Orphan Tsunami of 1700; USGS, Summary of 1811-1812 New Madrid Earthquakes Sequence; USGS, Casualties and damage after the 1906 Earthquake; USGS, M6.9 Loma Prieta earthquake page; USGS Open-File Report 96-263 (Northridge); NOAA NCEI Significant Earthquake Database; Insurance Information Institute, Facts + Statistics: Earthquakes and tsunamis (Aon data, January 2025); US Census Bureau cartographic boundary files (2023); DisasterAWARE Historical Hazards API (queried 2026-10-09).