Reviewed by USGSVanuatu23y ago
M5.1 earthquake 177 km SSE of Isangel, Vanuatu
Tuesday, January 20, 2004, 11:22:23 UTC · 21.021°S, 169.943°E
A magnitude 5.1 earthquake struck 177 km SSE of Isangel, Vanuatu on Tuesday, January 20, 2004, 11:22:23 UTC, at a depth of 102.4 km (intermediate). It is the strongest earthquake within 300 km since an M5.8 on January 12, 2004.
- Magnitude
- 5.1
- Moderate · mwc
- Depth
- 102 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 earthquakeDashed circle: 75 km aftershock search area
In context
How big was it, and why here?
Energy released
674 tons of TNT
That is about 1/22 of the Hiroshima bomb. It released about 1 times the energy of a magnitude 5.0.
Tectonic setting
107 km
from the nearest mapped plate boundary, between the New Hebrides and Australian plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.
Depth: intermediate
102 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 75 km
USGS lists 1 M2.5+ earthquake within 75 km in the following 30 days; the largest was M5.2 on February 15, 2004. 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 1,049 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 · 191 km NW of this epicenter
- 7.828 km ESE of Isangel, VanuatuJune 16, 1910 · 163 km N of this epicenter
- 7.7249 km E of Vao, New CaledoniaMay 16, 1995 · 221 km S of this epicenter
- 7.663 km NW of Isangel, VanuatuOctober 14, 1913 · 241 km NW of this epicenter
- 7.6274 km ESE of Tadine, New CaledoniaMarch 16, 1928 · 156 km S of this epicenter
- 7.5southeast of the Loyalty IslandsJanuary 4, 1998 · 174 km SE of this epicenter
- 7.447 km NW of Isangel, VanuatuOctober 11, 1992 · 223 km NW of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 21 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 · 188 km away
26 deathsSevere damage ($5–24M)tsunami
- 1901M7.9
Loyalty Islands
9 Aug 1901 · 109 km away
Moderate damage ($1–5M)tsunami
- 1920M8.1
Loyalty Islands
20 Sep 1920 · 191 km away
Limited damage (under $1M)tsunami
- 1878M7.5
Tanna Island
10 Jan 1878 · 271 km away
Limited damage (under $1M)tsunami
- 1913M8.1
Vanuatu Islands
14 Oct 1913 · 196 km away
- 1878M8.0
Vanuatu Islands
11 Feb 1878 · 271 km away
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.