U.S. state profile · USGS ComCat
Earthquakes in American Samoa
American Samoa ranks 17th of 38 U.S. states and territories by catalogued seismic activity - a state with limited seismic activity. Below: the full M6+ event history, magnitude and depth profile, and yearly trend.
- 24
- M4+ events (since 2005)
- 4
- Major M6+ (since 1900)
- M6.4
- Strongest
- ~1
- M4+ per year
The verdict
American Samoa has logged 24 M4+ earthquakes since 2005 and 4 major M6+ events since 1900, the strongest reaching magnitude 6.4.
- #17
- of 38 U.S. states by M4+ activity
- 24
- catalogued M4+ events (2005–present)
- M6.4
- strongest earthquake on record
- 4
- major M6+ events since 1900
Average catalogued magnitude is 4.7 - most events are moderate tremors felt but rarely damaging.
Major (M6+) earthquakes in American Samoa by year
Count of significant (magnitude 6.0+) events catalogued each year
- 1917
1917: 1 major (M6+) events
1
- 1925
1925: 1 major (M6+) events
1
- 1944
1944: 1 major (M6+) events
1
- 2003
2003: 1 major (M6+) events
1
What this shows American Samoa's most active year for major earthquakes was 1917 (1 M6+ events). Major-quake counts track the episodic release of tectonic stress, not a smooth trend.
Magnitude distribution of major events
Breakdown of the 4 significant (M6+) earthquakes on record for American Samoa.
M6.0–6.9
4
100.0%
Depth of major earthquakes
Hypocentral depth of the 4 M6+ events, shallow quakes shake the surface hardest. Average depth: 14 km.
Shallow (<70 km)
4
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.
PGA hazard tiers (50-year design life) - American Samoa - National Seismic Hazard Map 2023 (USGS NSHM)
Strongest earthquakes in American Samoa
The 4 most powerful events on record (USGS, since 1900).
| Mag | Location | Depth | Date |
|---|---|---|---|
| 6.4 | 188 km SW of Vailoatai, American Samoa | 15.0 km | Oct 11, 1944 |
| 6.3 | 171 km S of Vailoatai, American Samoa | 15.0 km | Jun 19, 1925 |
| 6.2 | 246 km SSE of Vaitogi, American Samoa | 10.0 km | Oct 7, 2003 |
| 6.2 | 211 km SSW of Vailoatai, American Samoa | 15.0 km | Jun 28, 1917 |
Significant earthquake record (4 events)
Every catalogued magnitude-6.0-and-above earthquake in American Samoa since 1900, most recent first.
| Mag | Location | Depth | Date |
|---|---|---|---|
| 6.2 | 246 km SSE of Vaitogi, American Samoa | 10.0 km | Oct 7, 2003 |
| 6.4 | 188 km SW of Vailoatai, American Samoa | 15.0 km | Oct 11, 1944 |
| 6.3 | 171 km S of Vailoatai, American Samoa | 15.0 km | Jun 19, 1925 |
| 6.2 | 211 km SSW of Vailoatai, American Samoa | 15.0 km | Jun 28, 1917 |
States with similar seismic activity
Comparable catalogued earthquake frequency to American Samoa.
Frequently asked questions
How many earthquakes hit American Samoa? ▼
What was the largest earthquake in American Samoa? ▼
How does American Samoa 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.