Reviewed by USGSNew Caledonia18y ago
M4.6 earthquake in Loyalty Islands, New Caledonia
Monday, August 4, 2008, 21:46:53 UTC · 21.471°S, 168.416°E
A magnitude 4.6 earthquake struck in Loyalty Islands, New Caledonia on Monday, August 4, 2008, 21:46:53 UTC, at a depth of 36.1 km (shallow). It is the strongest earthquake within 300 km since an M4.8 on July 26, 2008.
- Magnitude
- 4.6
- Light · mb
- Depth
- 36 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 earthquakeDashed circle: 50 km aftershock search area
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
53 km
from the nearest mapped plate boundary, between the New Hebrides and Australian plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
Depth: shallow
36 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 lists 1 M2.5+ earthquake within 50 km in the following 30 days; the largest was M4.5 on August 10, 2008. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 1,083 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.11920 Vanuatu EarthquakeSeptember 20, 1920 · 166 km N of this epicenter
- 7.828 km ESE of Isangel, VanuatuJune 16, 1910 · 239 km NE of this epicenter
- 7.7249 km E of Vao, New CaledoniaMay 16, 1995 · 229 km SE of this epicenter
- 7.663 km NW of Isangel, VanuatuOctober 14, 1913 · 271 km N of this epicenter
- 7.6274 km ESE of Tadine, New CaledoniaMarch 16, 1928 · 227 km SE of this epicenter
- 7.5southeast of the Loyalty IslandsJanuary 4, 1998 · 273 km E of this epicenter
- 7.447 km NW of Isangel, VanuatuOctober 11, 1992 · 253 km N of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 22 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 26 recorded deaths. The most severe:
- 1875M8.1
Loyalty Islands: Lifou Island
28 Mar 1875 · 164 km away
26 deathsSevere damage ($5–24M)tsunami
- 1901M7.9
Loyalty Islands
9 Aug 1901 · 174 km away
Moderate damage ($1–5M)tsunami
- 1920M8.1
Loyalty Islands
20 Sep 1920 · 166 km away
Limited damage (under $1M)tsunami
- 1878M7.5
Tanna Island
10 Jan 1878 · 275 km away
Limited damage (under $1M)tsunami
- 1913M8.1
Vanuatu Islands
14 Oct 1913 · 227 km away
- 1878M8.0
Vanuatu Islands
11 Feb 1878 · 275 km away
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.