Open AccessThe earthquake and tsunami of 1865 November 17: evidence for far‐field tsunami hazard from Tonga
Author(s) -
Okal Emile A.,
Borrero José,
Synolakis Costas E.
Publication year - 2004
Publication title -
geophysical journal international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0956-540X
DOI - 10.1111/j.1365-246x.2004.02177.x
Subject(s) - seismology , subduction , tsunami earthquake , geology , seismic hazard , moment magnitude scale , intraplate earthquake , earthquake prediction , tectonics , geometry , mathematics , scaling
SUMMARY Historical reports of an earthquake in Tonga in 1865 November identify it as the only event from that subduction zone which generated a far‐field tsunami observable without instruments. Run‐up heights reached 2 m in Rarotonga and 80 cm in the Marquesas Islands. Hydrodynamic simulations require a moment of 4 × 10 28 dyn cm , a value significantly larger than previous estimates of the maximum size of earthquake to be expected at the Tonga subduction zone. This warrants an upwards re‐evaluation of the tsunami risk from Tonga to the Cook Islands and the various Polynesian chains, which had hitherto been regarded as minor.