Earthquakes in Vanuatu are frequent and are sometimes accompanied by tsunami, though these events are not often destructive. The archipelago, which was formerly known as New Hebrides, lies atop a complex and active plate boundary in the southwestern Pacific Ocean.
Overall, the population in this region resides in structures that are highly vulnerable to earthquake shaking, though some resistant structures exist. Most buildings in Vanuatu are constructed with lumber.[1]
The primary tectonic feature of the 1200km (700miles) island chain is the New Hebrides Trench, the convergent boundary of the Australian and Pacific Plates. Along the Wadati–Benioff zone, earthquake activity has been observed as shallow, intermediate, and deep-focus events at depths of up to 700km (400miles). Volcanic activity is also present along this north-northwest trending and northeast-dipping oceanic trench.
While much of the island arc experiences intermediate-depth earthquakes along a Wadati–Benioff zone that dips steeply at 70°, the area adjacent to the d'Entrecasteaux Ridge does not. There is a corresponding gap in seismicity that occurs below 50km (30miles) where it intrudes into the subduction zone from the west. According to the NUVEL-1 global relative plate motion model, convergence is occurring at roughly 8cm (03inches) per year. The uncertainty, which also affects the Tonga arc, is due to the influence of spreading at the North Fiji Basin. Of the 58 M7 or greater events that occurred between 1909 and 2001, few were studied.[2]
| Date | Region | MMI | Deaths | Injuries | Comments | Ref | ||
|---|---|---|---|---|---|---|---|---|
| 2023-01-08 | Espiritu Santo | 7.0 | VII | Major damage | [3] [4] | |||
| 2018-12-16 | Ambrym | 5.5 | VI | Several houses destroyed | [5] [6] | |||
| 2018-08-21 | Pentecost | 6.5 | VII | 1 | Minor damage | [7] | ||
| 2010-12-25 | Tafea | 7.3 | V | 4 | Minor damage/tsunami | [8] [9] | ||
| 2010-08-10 | Shefa | 7.3 | VII | Buildings damaged/Power outages | [10] [11] | |||
| 2009-10-07 | Torba | 7.4 | VIII | |||||
| 2009-10-07 | Torba | 7.8 | VII | Tsunami | ||||
| 2009-10-07 | Torba | 7.7 | IX | |||||
| 2009-06-03 | 6.3 | VI | 4 | Landslides | [12] | |||
| 2009-05-29 | 5.7 | VI | 10 | Landslides / damage | [13] | |||
| 2007-08-01 | Sanma | 7.2 | VII | 1 | Many buildings damaged | [14] [15] | ||
| 2002-11-28 | 5.9 | VII | 3 | Landslides / damage | [16] | |||
| 2002-01-03 | 7.2 | X | Several | Rockslides / damage | [17] | |||
| 7.4 | VIII | 5–10 | 40–100 | Landslides / damage / five killed by tsunami | ||||
| 1999-08-22 | Ambrym | 6.6 | IX[18] | Foreshock / landslides | [19] | |||
| 1997-04-21 | 7.7 | VII | Some damage / tsunami | [20] | ||||
| 1992-10-11 | Tanna | 7.4 | VIII | [21] | ||||
| 1990-07-27 | 7.2 | VII | 2 | Moderate damage | [22] | |||
| 1973-12-29 | 7.2 | VIII | Moderate damage | |||||
| 1973-12-29 | 7.5 | VIII | Moderate damage | |||||
| 1971-10-27 | 6.8 | VI | 1 | Some | Severe damage | [23] | ||
| 1965-08-11 | 7.6 | IX | Moderate damage / tsunami | |||||
| 1910-11-10 | 7.3 | VI | Moderate damage / tsunami | |||||
| 1909-07-08 | Moderate damage / tsunami | |||||||
| Note: The inclusion criteria for adding events are based on WikiProject Earthquakes' notability guideline that was developed for stand alone articles. The principles described also apply to lists. In summary, only damaging, injurious, or deadly events should be recorded. | ||||||||
Sources