| 抄録（英）： |
The 1995 Hyogo-ken Nanbu Earthquake showed the devastating effects of large intraplate earthquakes. After it, much attention is being paid to these kind of geological structures. In this study, the potential seismic hazard that the Median Tectonic Line of Southwest Japan represents to the Akashi Kaikyo Bridge is investigated. Thus, a hypothetical M 8.0 earthquake, assumed to be generated by faulting along the seismic gap on this geological structure, is analyzed to synthesize long-period ground motions at the Akashi Kaikyo Bridge construction site. A two-fault-plane source mechanism, with total length of 105 km, and extending from western Kii Peninsula to eastern Shikoku, is assumed to generate this huge earthquake. The Empirical Green's Function method and earthquake records obtained by the Akashi Kaikyo array observation system are used for the synthesis. The synthetic signals show peak displacement values from 20 to 30 cm, and most of their acceleration response spectra are reasonably enveloped by the design spectra for the Akashi Kaikyo Bridge, which, considering the low probability of occurrence of a M 8.0 earthquake along this geological structure, show that the seismic hazard the Median Tectonic Line represents to the bridge is acceptably included in its design spectra.
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