Reviewed by USGSTonga20y ago
M4.7 earthquake 115 km SSE of Pangai, Tonga
Sunday, August 6, 2006, 12:04:35 UTC · 20.773°S, 173.908°W
A magnitude 4.7 earthquake struck 115 km SSE of Pangai, Tonga on Sunday, August 6, 2006, 12:04:35 UTC, at a depth of 10.0 km (shallow). It is the strongest earthquake within 300 km since an M5.2 on August 1, 2006.
- Magnitude
- 4.7
- Light · mb
- Depth
- 10 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
169 tons of TNT
That is about 1/89 of the Hiroshima bomb. A magnitude 5.0 releases about 3 times more energy.
Tectonic setting
39 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: shallow
10 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 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 1,108 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.0TongaJanuary 4, 1903 · 143 km NW of this epicenter
- 8.02006 Tonga EarthquakeMay 3, 2006 · 69 km N of this epicenter
- 7.8159 km W of Pangai, TongaDecember 14, 1950 · 237 km NW of this epicenter
- 7.8111 km SSE of Pangai, TongaJune 26, 1913 · 15 km NE of this epicenter
- 7.5110 km E of ‘Ohonua, TongaSeptember 8, 1948 · 50 km S of this epicenter
- 7.4103 km ESE of Neiafu, TongaFebruary 27, 1921 · 227 km NE of this epicenter
- 7.385 km ESE of Neiafu, TongaJanuary 2, 1907 · 199 km N of this epicenter
- 7.2108 km SE of Neiafu, TongaDecember 19, 1906 · 189 km NE of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 11 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:
- 1865M8.0
Tonga Islands
18 Nov 1865 · 148 km away
Limited damage (under $1M)tsunami
- 2006M7.9
Tonga Islands
3 May 2006 · 69 km away · intensity VII
Limited damage (under $1M)tsunami
- 1903M8.0
Tonga Islands
4 Jan 1903 · 143 km away
- 1948M7.9
Tonga Islands
8 Sep 1948 · 27 km away
tsunami
- 1902M7.8
Tonga Islands
9 Feb 1902 · 86 km away
- 1950M7.7
Tonga Islands
14 Dec 1950 · 260 km away · intensity VI
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.