Reviewed by USGSTonga115y ago
M6.9 earthquake 127 km S of Hihifo, Tonga
Thursday, May 8, 1913, 18:35:20 UTC · 17.090°S, 173.985°W
A magnitude 6.9 earthquake struck 127 km S of Hihifo, Tonga on Thursday, May 8, 1913, 18:35:20 UTC, at a depth of 170.0 km (intermediate). It is the strongest earthquake within 300 km since an M7.3 on January 2, 1907.
- Magnitude
- 6.9
- Strong · mB
- Depth
- 170 km
- Intermediate
- 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
338 kilotons of TNT
That is about 22 times the Hiroshima bomb. It released about 708 times the energy of a magnitude 5.0.
Tectonic setting
57 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: intermediate
170 km
Intermediate-depth earthquakes usually break inside a plate that is sinking into the mantle. Shaking spreads over a wide area but is gentler at the epicenter than a shallow quake of the same size.
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 2 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 1 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:
- 1865M8.0
Tonga Islands
18 Nov 1865 · 273 km away
Limited damage (under $1M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.