2:00 PM - 2:15 PM
[HDS10-19] An essential feature of the 1906 Colombia-Ecuador earthquake clarified by observed tsunami waveforms
Keywords:1906 Colombia-Ecuador earthquake, slip distribution , observed tsunami waveforms
The tide gauge records with the tsunami remain at several stations: Naos in Panama, Sandiego, San Francisco, and Honolulu in the United States, Hakodate, Ayukawa, Kushimoto, Hososhima, and Fukahori in Japan. However, their tsunami heights were very small at most of the stations in addition to a large noise comparable to the heights. Thus, we decided to use only two capable waveforms as target waveforms in slip inverse analysis of the earthquake, observed at Naos, where the observed tsunami height in the waveforms was the largest, and Honolulu. Next, some Green’s functions including proper dispersion effects for the tsunami waveforms were computed assuming source areas in the subduction zone as suggested by Kelleher (1972). A comparison of the arrival times between the Green’s functions and observed tsunami waveforms indicated that the source area should cover a longer area that extends from southwest to northeast than Kelleher (1972) suggested in order to reproduce both observed waveforms. Finally, a slip inverse analysis based on the Green’s functions and observed waveforms was conducted and indicated that a large local slip with 6 m occurred at a northern part of the assumed source area. This developed source model producing well tsunami waveforms at Naos and Honolulu was consistent with the results of previous studies to the earthquake and historical/recent seismicity around the subduction zone.