1997 Fiji-Tonga earthquake

1997 Fiji-Tonga earthquake
Date 14 October 1997
Magnitude Mw 7.8
Depth 167 km
Epicenter 22°06′04″S 176°46′19″W / 22.101°S 176.772°W

The 1997 Fiji-Tonga earthquake occurred on 14 October 1997 at 09:53 UTC. The earthquake occurred in south of the Fiji Islands, about 190 km WSW of Nuku'alofa, Tonga, and 255 km SE of Ndoi Island, Fiji. This earthquake is located in the central part of the Fiji-Tonga subduction zone. 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.[1] This earthquake could be felt in Wellington, New Zealand.[2][3]

Tectonic setting

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.[4] Mantle seismicity is active in this area.[5] There is a belt of deep earthquakes in the west of the Tonga Trench.[6] There are more earthquakes with focus depth h ≥ 300 km occurring in the Tonga-Kermadec region than in all other regions combined.[7]

With a depth of 167 km, 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.[8]

References

  1. ↑ http://epsc.wustl.edu/~tibi/papers/2001JB000361.pdf
  2. ↑ http://earthquake.usgs.gov/earthquakes/eqarchives/significant/sig_1997.php
  3. ↑ http://neic.usgs.gov/neis/eq_depot/1997/eq_971014/
  4. ↑ http://www.earth.ox.ac.uk/~tony/watts/Tonga_Louisville.html
  5. ↑ Earth's Catastrophic Past and Future: A Scientific Analysis of Information Channeled by Edgar Cayce by Hutton, W. and Eagle, J. (p. 59)
  6. ↑ Plate tectonics: how it works by Cox A., Hart, R. B. (p. 29)
  7. ↑ Deep Earthquakes by Frohlich, C. (p. 384)
  8. ↑ https://netfiles.uiuc.edu/wpchen/shared/Reprints_Wang-Ping_CHEN/60_BrudzinskiChenFlatSlabJGR_BW05.pdf