Reviewed by USGSVanuatu15y ago
M4.9 earthquake 99 km W of Isangel, Vanuatu
Saturday, March 19, 2011, 05:23:14 UTC · 19.399°S, 168.349°E
A magnitude 4.9 earthquake struck 99 km W of Isangel, Vanuatu on Saturday, March 19, 2011, 05:23:14 UTC, at a depth of 73.8 km (intermediate). It is the strongest earthquake within 300 km since an M5.0 on March 17, 2011.
- Magnitude
- 4.9
- Light · mb
- Depth
- 74 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: 50 km aftershock search area
In context
How big was it, and why here?
Energy released
338 tons of TNT
That is about 1/45 of the Hiroshima bomb. A magnitude 5.0 releases about 1 times more energy.
Tectonic setting
50 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: intermediate
74 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 lists 2 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M5.2 on March 19, 2011. 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 1,354 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 · 66 km S of this epicenter
- 7.999 km SW of Port-Vila, VanuatuDecember 2, 1950 · 136 km NW of this epicenter
- 7.828 km ESE of Isangel, VanuatuJune 16, 1910 · 128 km E of this epicenter
- 7.663 km NW of Isangel, VanuatuOctober 14, 1913 · 69 km NE of this epicenter
- 7.447 km NW of Isangel, VanuatuOctober 11, 1992 · 65 km E of this epicenter
- 7.363 km S of Port-Vila, VanuatuJuly 23, 1961 · 122 km N of this epicenter
- 7.3141 km W of Isangel, VanuatuDecember 25, 2010 · 54 km SW of this epicenter
- 7.371 km SW of Isangel, VanuatuApril 9, 2008 · 94 km SE of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 38 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 · 69 km away
26 deathsSevere damage ($5–24M)tsunami
- 1920M8.1
Loyalty Islands
20 Sep 1920 · 66 km away
Limited damage (under $1M)tsunami
- 1878M7.5
Tanna Island
10 Jan 1878 · 47 km away
Limited damage (under $1M)tsunami
- 1961M7.3
Vanuatu Islands
23 Jul 1961 · 109 km away · intensity VI
Limited damage (under $1M)tsunami
- 2010M7.3
Vanuatu Islands
25 Dec 2010 · 54 km away
Limited damage (under $1M)tsunami
- 2002M7.2
Efate, Port Vila
2 Jan 2002 · 207 km away
Limited damage (under $1M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.