M 8.0 earthquake – The 1917 Samoa-Tonga Earthquake
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Local time: Jun 25, 1917 · 18:19 (UTC-11:30)
GreatShallow · 15 km
Reviewed by a seismologist
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- Magnitude
- 8.0moment magnitude (mw)
- Depth
- 15 kmShallow earthquake
- Epicenter
- -14.996, -173.270207 km from Apia
- Energy released
- 15 megatons of TNTabout 1,005 × Hiroshima
- Felt reports
- —"Did You Feel It?" responses
- Shaking intensity
- —not estimated
- Aftershocks
- 2M2.5+ within 286 km, up to 60 days
- Significance
- 985USGS score, 0–1,000+
The strongest within 300 km on record
No earthquake this strong has been recorded this close since our catalog begins in 1900.
How strong was it?
Great earthquake. It released 15 megatons of TNT, 31,623 times the energy of a magnitude 5.0. Bars use the magnitude scale: every step is about 32 times more energy.
Aftershocks
2 earthquakes of M2.5+ within 286 km in the 60 days after.
The strongest earthquakes within 300 km
Since 1900, around Samoa.
- 8.1 2009 Samoa Earthquake Sep 29, 2009
- 7.8 146 km ESE of Hihifo, Tonga Dec 26, 1975
- 7.7 133 km NE of Hihifo, Tonga Sep 1, 1981
- 7.6 82 km WNW of Hihifo, Tonga May 10, 2023
- 7.6 199 km ESE of Hihifo, Tonga Apr 2, 1977
- 7.4 88 km NNE of Hihifo, Tonga Apr 7, 1995
- 7.2 117 km SSW of Hihifo, Tonga Jan 8, 2000
- 7.2 19 km ENE of Hihifo, Tonga Oct 15, 1984