Vanuatu earthquakes

M6.6 earthquake 91 km S of Port-Vila, Vanuatu

A magnitude 6.6 earthquake struck 91 km S of Port-Vila, Vanuatu on Tue, Sep 29, 1987, 1:46 AM GMT+12 (13:46 UTC), 25 km (16 mi) below the surface.

Port-Vila forecast More in Vanuatu

Map

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The earthquake

Magnitude: 6.6 (Mw, moment), strong
Magnitude from: USGS National Earthquake Information Center
Local time: Tue, Sep 29, 1987, 1:46 AM GMT+12
UTC: 1987-09-28 13:46:13 UTC
Depth: 25.1 km (15.6 mi), shallow
Epicenter: 18.546° S, 168.161° E
Region: Vanuatu
Strongest shaking: IV, light shaking
Tsunami flag: No
Status: Reviewed by a seismologist

Magnitude estimates

Different scales measure different things and differ by a few tenths. The USGS marks one as preferred, and it is the one this page uses.

Mag.	Scale	Computed by	Notes
6.6	Mw, moment	USGS National Earthquake Information Center	Preferred · Reviewed
6.53	Mw, moment	ISC-GEM global catalog	Final · ±0.1
6.5	Mwc, centroid moment	Global CMT project	Preliminary
6.35	Me, energy	Choy, USGS energy magnitude	Reviewed

What happened

The USGS’s account of the effects of this earthquake.

FAULT PLANE SOLUTION: P-Waves NP1:Strike=163 Dip=73 Slip=90 NP2:Strike=343 Dip=17 Slip=90 Principal Axes: (T) Plg=62 Azm=73 (P) Plg=28 Azm=253 Comment: The focal mechanism is poorly controlled and corresponds to reverse faulting. The preferred fault plane is NP2. RADIATED ENERGY No. of sta: 6 Focal mech. M Energy 8.3+2.1*10**13 Nm MOMENT TENSOR SOLUTION Dep 27 No. of sta: 12 Moment Tensor; Scale 10**18 Nm Mrr=5.30 Mtt=-0.10 Mff=-5.20 Mrt=1.31 Mrf=-5.01 Mtf=1.04 Principal axes: (T) Val=7.41 Plg=68 Azm=73 (N) Val=0.09 Plg=2 Azm=167 (P) Val=-7.49 Plg=22 Azm=258 Best Double Couple:Mo=7.4*10**18 NP1:Strike=352 Dip=23 Slip=95 NP2:Strike=166 Dip=67 Slip=88 CENTROID, MOMENT TENSOR (HRV) Data Used: GDSN L.P.B.: 21S, 52C M.W.: 19S, 41C Centroid Location: Origin Time 13:46:25.7 0.2 Lat 18.40S 0.02 Lon 167.86E 0.02 Dep 21.8 0.9 Half-duration 7.6 Moment Tensor; Scale 10**18 Nm Mrr=5.70 0.09 Mtt=-0.39 0.07 Mff=-5.31 0.08 Mrt=2.58 0.24 Mrf=-4.21 0.31 Mtf=1.95 0.06 Principal Axes: (T) Val=7.57 Plg=69 Azm=49 (N) Val=0.17 Plg=6 Azm=156 (P) Val=-7.74 Plg=20 Azm=248 Best Double Couple:Mo=7.6*10**18 NP1:Strike=349 Dip=26 Slip=105 NP2:Strike=153 Dip=65 Slip=83

From the USGS event page for usp00038te. U.S. Geological Survey text and figures are in the public domain.

Shaking

The USGS ShakeMap: shaking estimated from seismic stations and the quake’s size, on the Modified Mercalli intensity scale.

Strongest estimated: IV, light shaking
Peak ground acceleration: 4.5% of gravity
Peak ground velocity: 1.5 cm/s
Map: Automatic

USGS ShakeMap: estimated shaking intensity around the epicenter — Estimated shaking intensity. Map: USGS ShakeMap.

Did you feel it?

No one has reported feeling this quake to the USGS.

How well it is located

Reviewed by a seismologist.

Depth from: CONSTRAINED_BY_DEPTH_PHASES

Nearest places

Distance and direction from each place to the epicenter, with its forecast.

Port-Vila, VanuatuPopulation 35,901. Forecast91 kmS

Nearby

Within 100 km, magnitude 3.6 and up: 11 in the 60 days after this one and 5 in the 30 days before it.

After

Before

Earthquakes today Vanuatu earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event usp00038te (also filed as choy19870928134613, gcmtc092887e, gcmt19870928134615, atlas19870928134616, iscgem458580). Read Sun, Oct 4, 2026, 9:37 PM UTC.