U.S. state profile · USGS ComCat
Earthquakes in Guam
Guam ranks 3rd of 38 U.S. states and territories by catalogued seismic activity - one of the most seismically active U.S. jurisdictions. Below: the full M6+ event history, magnitude and depth profile, and yearly trend.
- 2,453
- M4+ events (since 2005)
- 42
- Major M6+ (since 1900)
- M7.8
- Strongest
- ~117
- M4+ per year
The verdict
Guam has logged 2,453 M4+ earthquakes since 2005 and 42 major M6+ events since 1900, the strongest reaching magnitude 7.8.
- #3
- of 38 U.S. states by M4+ activity
- 2,453
- catalogued M4+ events (2005–present)
- M7.8
- strongest earthquake on record
- 42
- major M6+ events since 1900
Average catalogued magnitude is 4.5 - most events are moderate tremors felt but rarely damaging.
Major (M6+) earthquakes in Guam by year
Count of significant (magnitude 6.0+) events catalogued each year
- 1997
1997: 2 major (M6+) events
2
- 1998
1998: 2 major (M6+) events
2
- 1999
1999: 1 major (M6+) events
1
- 2000
2000: 2 major (M6+) events
2
- 2001
2001: 1 major (M6+) events
1
- 2002
2002: 1 major (M6+) events
1
- 2005
2005: 1 major (M6+) events
1
- 2008
2008: 1 major (M6+) events
1
- 2010
2010: 1 major (M6+) events
1
- 2014
2014: 1 major (M6+) events
1
- 2022
2022: 1 major (M6+) events
1
- 2025
2025: 1 major (M6+) events
1
What this shows Guam's most active year for major earthquakes was 1917 (3 M6+ events). Major-quake counts track the episodic release of tectonic stress, not a smooth trend.
Magnitude distribution of major events
Breakdown of the 42 significant (M6+) earthquakes on record for Guam.
M7.0–7.9
7
16.7%
M6.0–6.9
35
83.3%
Depth of major earthquakes
Hypocentral depth of the 42 M6+ events, shallow quakes shake the surface hardest. Average depth: 53 km.
Shallow (<70 km)
30
71% of events
Intermediate (70–300 km)
12
28.6% 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) - Guam - National Seismic Hazard Map 2023 (USGS NSHM)
Strongest earthquakes in Guam
The 10 most powerful events on record (USGS, since 1900).
| Mag | Location | Depth | Date |
|---|---|---|---|
| 7.8 | 32 km S of Inarajan Village, Guam | 59.3 km | Aug 8, 1993 |
| 7.2 | 265 km S of Merizo Village, Guam | 15.0 km | Jan 28, 1931 |
| 7.1 | 261 km S of Merizo Village, Guam | 15.0 km | May 9, 1917 |
| 7.1 | 20 km SSW of Merizo Village, Guam | 85.7 km | Apr 26, 2002 |
| 7.0 | 98 km SSE of Inarajan Village, Guam | 15.0 km | Dec 9, 1909 |
| 7.0 | 69 km SSE of Inarajan Village, Guam | 37.0 km | Oct 12, 2001 |
| 7.0 | 32 km NNE of Yigo Village, Guam | 180.0 km | Oct 26, 1912 |
| 6.8 | 181 km WSW of Merizo Village, Guam | 76.0 km | May 9, 2008 |
| 6.7 | 43 km NW of Piti Village, Guam | 130.0 km | Sep 17, 2014 |
| 6.5 | 276 km SW of Merizo Village, Guam | 22.9 km | Oct 23, 1971 |
Significant earthquake record (42 events)
Every catalogued magnitude-6.0-and-above earthquake in Guam since 1900, most recent first.
| Mag | Location | Depth | Date |
|---|---|---|---|
| 6.0 | 191 km WSW of Merizo Village, Guam | 65.0 km | Nov 4, 2025 |
| 6.0 | 168 km SSW of Merizo Village, Guam | 15.0 km | Feb 13, 2022 |
| 6.7 | 43 km NW of Piti Village, Guam | 130.0 km | Sep 17, 2014 |
| 6.3 | 272 km SSE of Inarajan Village, Guam | 13.0 km | Jul 10, 2010 |
| 6.8 | 181 km WSW of Merizo Village, Guam | 76.0 km | May 9, 2008 |
| 6.3 | 63 km NNW of Yigo Village, Guam | 158.7 km | Feb 2, 2005 |
| 7.1 | 20 km SSW of Merizo Village, Guam | 85.7 km | Apr 26, 2002 |
| 7.0 | 69 km SSE of Inarajan Village, Guam | 37.0 km | Oct 12, 2001 |
| 6.2 | 166 km S of Merizo Village, Guam | 33.0 km | Dec 19, 2000 |
| 6.2 | 30 km NNW of Yigo Village, Guam | 132.2 km | Feb 26, 2000 |
| 6.0 | 45 km SSW of Merizo Village, Guam | 50.9 km | Dec 19, 1999 |
| 6.0 | 229 km SW of Merizo Village, Guam | 9.2 km | Sep 22, 1998 |
| 6.0 | 71 km N of Yigo Village, Guam | 154.1 km | May 15, 1998 |
| 6.0 | 8 km SSE of Merizo Village, Guam | 29.0 km | May 9, 1997 |
| 6.5 | 49 km N of Yigo Village, Guam | 100.8 km | Apr 23, 1997 |
| 6.0 | 41 km SE of Inarajan Village, Guam | 18.3 km | Aug 16, 1993 |
| 6.2 | 91 km ESE of Yigo Village, Guam | 21.6 km | Aug 11, 1993 |
| 7.8 | 32 km S of Inarajan Village, Guam | 59.3 km | Aug 8, 1993 |
| 6.0 | 54 km NNW of Yigo Village, Guam | 155.7 km | Feb 10, 1991 |
| 6.0 | 120 km SSW of Merizo Village, Guam | 31.9 km | May 31, 1985 |
| 6.1 | 61 km ENE of Yigo Village, Guam | 98.0 km | Sep 22, 1984 |
| 6.1 | 235 km SW of Merizo Village, Guam | 33.0 km | Sep 17, 1977 |
| 6.1 | 36 km NNW of Yigo Village, Guam | 113.0 km | Nov 1, 1975 |
| 6.2 | 294 km WSW of Merizo Village, Guam | 20.0 km | Oct 24, 1971 |
| 6.5 | 293 km WSW of Merizo Village, Guam | 15.0 km | Oct 24, 1971 |
| 6.5 | 276 km SW of Merizo Village, Guam | 22.9 km | Oct 23, 1971 |
| 6.0 | 20 km SW of Merizo Village, Guam | 30.0 km | Sep 16, 1970 |
| 6.2 | 148 km SW of Merizo Village, Guam | 17.9 km | Mar 4, 1970 |
| 6.0 | 134 km E of Yigo Village, Guam | 15.0 km | Jan 13, 1959 |
| 6.2 | 283 km SW of Merizo Village, Guam | 15.0 km | Aug 2, 1950 |
| 6.2 | 121 km SSW of Merizo Village, Guam | 25.0 km | Jun 12, 1946 |
| 6.0 | 70 km SE of Inarajan Village, Guam | 35.0 km | Jan 30, 1937 |
| 6.2 | 40 km E of Yigo Village, Guam | 35.0 km | Dec 13, 1936 |
| 6.4 | 46 km ENE of Yigo Village, Guam | 70.0 km | Oct 29, 1936 |
| 6.2 | 254 km S of Merizo Village, Guam | 15.0 km | Mar 15, 1932 |
| 7.2 | 265 km S of Merizo Village, Guam | 15.0 km | Jan 28, 1931 |
| 6.0 | 206 km SW of Merizo Village, Guam | 20.0 km | May 1, 1929 |
| 6.3 | 146 km WSW of Merizo Village, Guam | 15.0 km | Nov 24, 1917 |
| 7.1 | 261 km S of Merizo Village, Guam | 15.0 km | May 9, 1917 |
| 6.4 | 279 km S of Merizo Village, Guam | 15.0 km | May 6, 1917 |
| 7.0 | 32 km NNE of Yigo Village, Guam | 180.0 km | Oct 26, 1912 |
| 7.0 | 98 km SSE of Inarajan Village, Guam | 15.0 km | Dec 9, 1909 |
States with similar seismic activity
Comparable catalogued earthquake frequency to Guam.
Northern Mariana Islands
3,322 M4+ events · strongest M7.7
California
877 M4+ events · strongest M7.2
Puerto Rico
296 M4+ events · strongest M6.4
Oregon
263 M4+ events · strongest M6.3
U.S. Virgin Islands
220 M4+ events · strongest M6.1
Hawaii
203 M4+ events · strongest M6.9
Frequently asked questions
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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.
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