1997 Fiji-Tonga earthquake

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

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]

Earthquake

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]

References

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