Reviewed by USGSTonga20y ago
M4.5 earthquake 158 km NW of Neiafu, Tonga
Sunday, August 6, 2006, 20:53:06 UTC · 17.624°S, 175.030°W
A magnitude 4.5 earthquake struck 158 km NW of Neiafu, Tonga on Sunday, August 6, 2006, 20:53:06 UTC, at a depth of 35.0 km (shallow). It is the strongest earthquake within 300 km since an M5.2 on August 2, 2006.
- Magnitude
- 4.5
- Light · mb
- 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
85 tons of TNT
That is about 1/178 of the Hiroshima bomb. A magnitude 5.0 releases about 6 times more energy.
Tectonic setting
46 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 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 1,300 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 · 285 km E of this epicenter
- 8.0TongaJanuary 4, 1903 · 264 km S of this epicenter
- 7.8159 km W of Pangai, TongaDecember 14, 1950 · 248 km S of this epicenter
- 7.4103 km ESE of Neiafu, TongaFebruary 27, 1921 · 254 km SE of this epicenter
- 7.385 km ESE of Neiafu, TongaJanuary 2, 1907 · 243 km SE of this epicenter
- 7.3201 km ENE of Neiafu, TongaOctober 6, 1987 · 299 km E of this epicenter
- 7.2108 km SE of Neiafu, TongaDecember 19, 1906 · 266 km SE of this epicenter
- 7.2Fiji regionMarch 31, 1907 · 210 km W of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 9 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:
- 1919M8.1
Tonga Islands
30 Apr 1919 · 278 km away
Limited damage (under $1M)tsunami
- 1865M8.0
Tonga Islands
18 Nov 1865 · 264 km away
Limited damage (under $1M)tsunami
- 1903M8.0
Tonga Islands
4 Jan 1903 · 264 km away
- 1902M7.8
Tonga Islands
9 Feb 1902 · 286 km away
- 1950M7.7
Tonga Islands
14 Dec 1950 · 232 km away · intensity VI
- 1913M7.6
Tonga Islands
26 Jun 1913 · 286 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.