7.4 Earthquake struck Kermadec Islands Region – Oct 21, 2011

A massive 7.4 earthquake struck the Kermadec trench area. The closest island at several hundred km was Raoul Island

Earthquakes 6+

From September 22. 2011 to October 21, 2011 (17 Quakes)

6.2 Alaska on  Sept. 14 / 6.0 Cuba , 6.1 Nw. Zealand , 6.2 Japan , 7.3 Fiji all on Sept. 15 / 6.6 Japan , 6.0 Japan both on Sept.16 / 6.9 India on Sept. 18 / 6.4 Tonga on Sept. 22 / 6.2 Argentina on Oct. 6 / 6.1 Kermadec Islands on Oct. 7/6.8 Bali on Oct.13/6.7 Papua Nw. Guinea, 6.1 Amurskaya Russia both on Oct.14/6.3 Papua Nw. Guinea on Oct.18/ 6.1 Hokkaido Japan Region on Oct.21 / 7.4 Kermadec Islands Region on Oct. 21/

Magnitude 7.4
Date-Time
Location 28.998°S, 176.183°W
Depth 32.9 km (20.4 miles)
Region KERMADEC ISLANDS REGION
Distances 169 km (105 miles) E of Raoul Island, Kermadec Islands
375 km (233 miles) NE of L’Esperance Rock, Kermadec Islands
877 km (544 miles) S of NUKU`ALOFA, Tonga
1215 km (754 miles) NE of Auckland, New Zealand
Location Uncertainty horizontal +/- 14.1 km (8.8 miles); depth +/- 2.7 km (1.7 miles)
Parameters NST=741, Nph=742, Dmin=172.5 km, Rmss=0.68 sec, Gp= 11°,
M-type=”moment” magnitude from initial P wave (tsuboi method) (Mi/Mwp), Version=8
Source
  • Magnitude: USGS NEIC (WDCS-D)
    Location: USGS NEIC (WDCS-D)
Event ID usb0006b6p

*

TSUNAMI BULLETIN NUMBER 002

PACIFIC TSUNAMI WARNING CENTER/NOAA/NWS

ISSUED AT 1844Z 21 OCT 2011

EVALUATION

SEA LEVEL READINGS INDICATE A TSUNAMI WAS GENERATED.

IT MAY HAVE BEEN DESTRUCTIVE ALONG COASTS NEAR THE

EARTHQUAKE EPICENTER. FORTHOSE AREAS –

WHEN NO MAJOR WAVES ARE OBSERVED FOR TWO HOURS

AFTER THE ESTIMATED TIME OF ARRIVAL OR DAMAGING WAVES

HAVE NOT OCCURRED FOR AT LEAST TWO HOURS THEN LOCAL

AUTHORITIES CAN ASSUME THE THREAT IS PASSED. DANGER TO

BOATS AND COASTAL STRUCTURES CAN CONTINUE FOR SEVERAL HOURS

DUE TO THE CONTINUING SEA LEVEL CHANGES AND RAPID CURRENTS.

AS LOCAL CONDITIONS CAN CAUSE A WIDE VARIATION IN TSUNAMI WAVE

ACTION THE ALL CLEAR DETERMINATION MUST BE MADE BY

LOCAL AUTHORITIES.

NO TSUNAMI THREAT EXISTS FOR OTHER COASTAL AREAS IN THE PACIFIC

ALTHOUGH SOME OTHER AREAS MAY EXPERIENCE SMALL NON-DESTRUCTIVE

SEA LEVEL CHANGES LASTING UP TO SEVERAL HOURS.

Source and author: earthquake.usgs.gov * ptwc.weather.gov

5 responses to “7.4 Earthquake struck Kermadec Islands Region – Oct 21, 2011

  1. 7.4 is huge! I am surprised there was no mention of any damage!

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  2. There was no damage reported because the Kermadec Islands are quite some distance from the NZ Mainland. Not much to damage on Raoul Island either.

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  3. So after a lull in magnitude 6 on the ritcher scales we then had the sixes plus just lately …NOW THE SEVENS HAVE STARTED !!!???

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