Reviewed by USGSGuam118y ago
M7.0 earthquake 98 km SSE of Inarajan Village, Guam
Thursday, December 9, 1909, 23:28:45 UTC · 12.408°N, 144.951°E
A magnitude 7.0 earthquake struck 98 km SSE of Inarajan Village, Guam on Thursday, December 9, 1909, 23:28:45 UTC, at a depth of 15.0 km (shallow). No earthquake of this size or larger appears within 300 km in the USGS catalog since 1900.
- Magnitude
- 7.0
- Major · mw
- Depth
- 15 km
- Shallow
- Felt reports
- 0
- Did You Feel It?
- Est. shaking
- —
- No ShakeMap
- PAGER alert
- None
- Not issued
- Tsunami
- No flag
- USGS feed
Outlined circle: this earthquake
In context
How big was it, and why here?
Energy released
494 kilotons of TNT
That is about 33 times the Hiroshima bomb. It released about 1,035 times the energy of a magnitude 5.0.
Tectonic setting
23 km
from the nearest mapped plate boundary, between the Mariana and Pacific plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
Depth: shallow
15 km
Shallow earthquakes (under 70 km) produce the strongest surface shaking for their size, so they are the ones most likely to cause damage near the epicenter.
Did You Feel It?
Where it was felt
No “Did You Feel It?” reports have been published for this event yet. If you felt it, you can add your report on the USGS website.
I felt it — report to USGS ↗USGS PAGER estimate
Who was exposed to shaking
USGS publishes PAGER impact estimates for significant earthquakes, usually within an hour. No PAGER estimate is available for this event.
After the main event
Aftershocks within 200 km
USGS has not published any M2.5+ earthquake within 200 km in the 30 days after this event.
Regional history
Past M5+ earthquakes within 300 km
USGS lists no earlier M5.0+ earthquakes within 300 km.
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 7 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:
- 1849M7.5
Guam
25 Jan 1849 · 252 km away · intensity IX
Severe damage ($5–24M)tsunami
- 1909M8.0
Guam
9 Dec 1909 · 12 km away · intensity VIII
Moderate damage ($1–5M)tsunami
- 1892M7.5
Guam
16 May 1892 · 252 km away · intensity VIII
Moderate damage ($1–5M)tsunami
- 1825
Ladrones Island
Apr 1825 · 252 km away · intensity VIII
Moderate damage ($1–5M)tsunami
- 1834
Agana
May 1834 · 252 km away
Moderate damage ($1–5M)
- 1903
Guam
10 Feb 1903 · 252 km away · intensity VII
Limited damage (under $1M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.