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Report on False Reports (Unknown) — November 1986

False Reports

Bulletin of the Global Volcanism Network, vol. 11, no. 11 (November 1986)
Managing Editor: Lindsay McClelland.

False Reports (Unknown) Kermadec Islands: Probably an earthquake in the Tonga Trench

Please cite this report as:

Global Volcanism Program, 1986. Report on False Reports (Unknown) (McClelland, L., ed.). Bulletin of the Global Volcanism Network, 11:11. Smithsonian Institution.

False Reports


Lat Unknown, Unknown; summit elev. m

All times are local (unless otherwise noted)

The 11 November submarine explosion is now believed to have been an earthquake. To persons on board the yacht Nutra, the event sounded like a dynamite blast followed by a pair of echoes with a total duration of 1 second. Intensities of the blast and echoes were estimated by crewmen at 100, 90, and 80 decibels. No pumice, ash, or water discoloration were observed.

P and S waves, apparently from this event, were recorded at Rarotonga, Cook Islands, and Mangahao, New Zealand; local magnitude was about 4.5-5. The yacht's position at the time of the event, over the W side of the Tonga Trench, was determined by satellite navigation, accurate to within ~1.5 km.

Geological Summary. False or otherwise incorrect reports of volcanic activity.

Information Contacts: J. Latter, DSIR Geophysics Division, Wellington; P. Black, Univ of Auckland, Auckland.