1997 Fiji-Tonga earthquake

From Wikipedia, the free encyclopedia
Jump to: navigation, search
1997 Fiji-Tonga earthquake
1997 Fiji-Tonga earthquake is located in Oceania
1997 Fiji-Tonga earthquake
Date 14 October 1997
Magnitude Mw 7.8
Depth 167 km (104 mi)
Epicenter 22°06′04″S 176°46′19″W / 22.101°S 176.772°W / -22.101; -176.772

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).[1] This earthquake could be felt in Wellington, New Zealand.[2][3]

Tectonic setting[edit]

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 (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.[8]


  1. ^ http://epsc.wustl.edu/~tibi/papers/2001JB000361.pdf
  2. ^ "Archived copy". Archived from the original on 7 June 2011. Retrieved 2015-02-15. 
  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