Magnitude 6.9 - KERMADEC ISLANDS REGION

2009 February 18 21:53:44 UTC

Versión en Español

Earthquake Details

Magnitude6.9
Date-Time
Location27.464°S, 176.324°W
Depth25 km (15.5 miles) set by location program
RegionKERMADEC ISLANDS REGION
Distances250 km (155 miles) NE of Raoul Island, Kermadec Islands
510 km (315 miles) NNE of L'Esperance Rock, Kermadec Islands
1335 km (830 miles) NE of Auckland, New Zealand
1740 km (1080 miles) NNE of WELLINGTON, New Zealand
Location Uncertaintyhorizontal +/- 6.8 km (4.2 miles); depth fixed by location program
ParametersNST=222, Nph=222, Dmin=>999 km, Rmss=1.02 sec, Gp= 25°,
M-type=regional moment magnitude (Mw), Version=7
Source
  • USGS NEIC (WDCS-D)
Event IDus2009dfch
  • This event has been reviewed by a seismologist.
  • Did you feel it? Report shaking and damage at your location. You can also view a map displaying accumulated data from your report and others.

Earthquake Summary

Small globe showing earthquakeSmall map showing earthquake

Earthquake Summary Poster

Felt Reports

Felt at Wellington.

Tectonic Summary

The February 18, 2009, M6.9 earthquake occurred in the Tonga - Kermadec subduction zone. The subduction zone extends north-northeast from the North Island of New Zealand for over 2500 km through Tonga to within 100 km of Western Samoa. At a broad scale, tectonics of the subduction zone reflect the motion of the Pacific plate westward with respect to the interior of the Australia plate at a velocity of about 60 mm/y in the epicentral region of the earthquake. The Pacific plate subducts beneath the Australia plate at the Tonga and Kermadec trenches, and dips to the west. In detail, the eastern edge of the broad Australia plate may itself be viewed as a collection of small plates or microplates that move with respect to each other and with respect to the Pacific plate and the Australia plate interior. The location and focal-mechanism of the earthquake are consistent with it occurring as thrust faulting on the interface between the subducting Pacific plate and the overriding Australia plate (in detail, the overriding Kermadec microplate).

The interaction between the Pacific and Australia plate creates one of the most active tectonic environments in the world, with a high level of associated earthquake activity. Since 1976, a 200-km long section of the Tonga - Kermadec subduction zone that includes the epicenter of the February 18 earthquake has produced over 50 earthquakes of magnitude 6 or larger, with the largest having magnitude 7.9.

Tsunami Information Tsunami Information