Open Access

Seafloor displacement at Kumano-nada caused by the 2004 off Kii Peninsula earthquakes, detected through repeated GPS/Acoustic surveys

Earth, Planets and Space200658:BF03351996

Received: 24 January 2006

Accepted: 15 March 2006

Published: 26 July 2006


In 2004, we started monitoring crustal deformation at Kumano-nada in the Nankai trough using the GPS/Acoustic technique. We observed a large southward seafloor displacement of 30 cm associated with the off Kii Peninsula earthquake, which occurred in September 2004, between our two survey campaigns in August and November 2004. The observed seafloor displacement is larger than that predicted from a slip model derived solely from GPS measurements on land. This may indicate the earthquake fault is slightly shallower and extends move to the NW than previously estimated.

Key words

GPS/Acoustic measurementseafloor displacementKumano-nada2004 off Kii Peninsula earthquake