Reviewed by USGSTonga20y ago
M4.6 earthquake 60 km ENE of Pangai, Tonga
Thursday, August 31, 2006, 08:18:57 UTC · 19.663°S, 173.798°W
A magnitude 4.6 earthquake struck 60 km ENE of Pangai, Tonga on Thursday, August 31, 2006, 08:18:57 UTC, at a depth of 91.6 km (intermediate). It is the strongest earthquake within 300 km since an M4.8 on August 25, 2006.
- Magnitude
- 4.6
- Light · mb
- Depth
- 92 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
120 tons of TNT
That is about 1/126 of the Hiroshima bomb. A magnitude 5.0 releases about 4 times more energy.
Tectonic setting
78 km
from the nearest mapped plate boundary, between the Tonga and Pacific plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
Depth: intermediate
92 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 50 km
USGS has not published any M2.5+ earthquake within 50 km in the 30 days after this event.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 1,201 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.11919 Tonga EarthquakeApril 30, 1919 · 206 km NE of this epicenter
- 8.0TongaJanuary 4, 1903 · 131 km W of this epicenter
- 8.02006 Tonga EarthquakeMay 3, 2006 · 67 km SW of this epicenter
- 7.8159 km W of Pangai, TongaDecember 14, 1950 · 217 km W of this epicenter
- 7.8111 km SSE of Pangai, TongaJune 26, 1913 · 113 km S of this epicenter
- 7.5110 km E of ‘Ohonua, TongaSeptember 8, 1948 · 174 km S of this epicenter
- 7.4103 km ESE of Neiafu, TongaFebruary 27, 1921 · 116 km NE of this epicenter
- 7.385 km ESE of Neiafu, TongaJanuary 2, 1907 · 84 km NE of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 13 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:
- 1919M8.1
Tonga Islands
30 Apr 1919 · 199 km away
Limited damage (under $1M)tsunami
- 1865M8.0
Tonga Islands
18 Nov 1865 · 36 km away
Limited damage (under $1M)tsunami
- 2006M7.9
Tonga Islands
3 May 2006 · 67 km away · intensity VII
Limited damage (under $1M)tsunami
- 1903M8.0
Tonga Islands
4 Jan 1903 · 131 km away
- 1948M7.9
Tonga Islands
8 Sep 1948 · 150 km away
tsunami
- 1902M7.8
Tonga Islands
9 Feb 1902 · 43 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.