Reviewed by USGSTonga110y ago
M6.5 earthquake 77 km SSW of Pangai, Tonga
Sunday, June 24, 1917, 19:48:48 UTC · 20.437°S, 174.703°W
A magnitude 6.5 earthquake struck 77 km SSW of Pangai, Tonga on Sunday, June 24, 1917, 19:48:48 UTC, at a depth of 35.0 km (shallow). It is the strongest earthquake within 300 km since an M7.8 on June 26, 1913.
- Magnitude
- 6.5
- Strong · mw
- Depth
- 35 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
97 kilotons of TNT
That is about 6 times the Hiroshima bomb. It released about 204 times the energy of a magnitude 5.0.
Tectonic setting
97 km
from the nearest mapped plate boundary, between the Tonga and Niuafo'ou plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
Depth: shallow
35 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 100 km
USGS has not published any M2.5+ earthquake within 100 km in the 30 days after this event.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 9 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.0TongaJanuary 4, 1903 · 58 km NW of this epicenter
- 7.8111 km SSE of Pangai, TongaJune 26, 1913 · 97 km E of this epicenter
- 7.385 km ESE of Neiafu, TongaJanuary 2, 1907 · 211 km NE of this epicenter
- 7.2108 km SE of Neiafu, TongaDecember 19, 1906 · 210 km NE of this epicenter
- 7.2241 km WNW of Houma, TongaAugust 21, 1911 · 272 km W of this epicenter
- 7.0254 km WNW of Houma, TongaApril 20, 1910 · 297 km W of this epicenter
- 6.915 km WSW of Pangai, TongaFebruary 27, 1905 · 67 km N of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 6 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:
- 1865M8.0
Tonga Islands
18 Nov 1865 · 163 km away
Limited damage (under $1M)tsunami
- 1903M8.0
Tonga Islands
4 Jan 1903 · 58 km away
- 1902M7.8
Tonga Islands
9 Feb 1902 · 88 km away
- 1913M7.6
Tonga Islands
26 Jun 1913 · 88 km away
- 1853
Tonga Trench
24 Dec 1853 · 94 km away
tsunami
- 1907
S Of Tonga
1907 · 134 km away
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.