1997 Fiji-Tonga earthquake
|Date||14 October 1997|
|Depth||167 km (104 mi)|
The 1997 Fiji-Tonga earthquake occurred south of the Fiji Islands (about 190 km WSW of Nuku'alofa, Tonga, and 255 km SE of Ndoi Island) on 14 October at 09:53 UTC. This earthquake was located in the central part of the Fiji-Tonga subduction zone and it had a magnitude of Mw 7.8. The rupture area was about ~50 km × 25 km, and the average slip was estimated to be 6 m (20 ft). This earthquake could be felt in Wellington, New Zealand.
The Pacific Plate is subducting beneath the Australian Plate in the Fiji-Tonga subduction zone. The Tonga Trench is linear, fast converging, and seismically active. Mantle seismicity is active in this area. There is a belt of deep earthquakes in the west of the Tonga Trench. There are more earthquakes with focus depth h ≥ 300 km occurring in the Tonga-Kermadec region than in all other regions combined.
With a depth of 167 km (104 mi), this was an intermediate depth earthquake. Thermo-petrologic models suggest that water may have an important role in the generating process for earthquakes of intermediate depths, as hydrous minerals may exist where intermediate depth seismicity is abundant.
- "Archived copy". Archived from the original on 7 June 2011. Retrieved 2015-02-15.
- Earth's Catastrophic Past and Future: A Scientific Analysis of Information Channeled by Edgar Cayce by Hutton, W. and Eagle, J. (p. 59)
- Plate tectonics: how it works by Cox A., Hart, R. B. (p. 29)
- Deep Earthquakes by Frohlich, C. (p. 384)