Earth Planets Space, Vol. 60 (No. 2), pp. 127-132, 2008LETTER
Yuichi Namegaya and Kenji Satake
Active Fault Research Center, Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba 305-8567, Japan
(Received July 2, 2007; Revised October 11, 2007; Accepted October 23, 2007; Online published February 19, 2008)
Tsunami numerical simulations of the 2007 Noto Hanto earthquake are carried out for three models based on the coastal vertical movements, the GPS observations, and the strong-motion data. The three fault models produce similar tsunami waveforms at five tide gauge stations around the source. Comparisons with the observed tsunami waveforms indicate that the fault model based on the coastal movements shows the best agreement but that a slightly smaller fault area with a larger slip amount would make the agreement better. At three tide gauge stations in Toyama Bay, unusual oscillatory waves were recorded before the expected tsunami arrival. The spectral analysis of the observed records indicates that they represent characteristic oscillation of Toyama Bay, and modal calculations show that they can be reproduced by the water displacement in the mouth of Nanao Bay generated by a possible extension of the mainshock fault toward the southeast or a possible landslide source at a steep part of ocean bottom.
Key words: The 2007 Noto Hanto earthquake, tide gauge records, tsunami numerical simulation, fault models, oscillation of Toyama Bay.