日本沿岸における遠地津波のエネルギー分布
1989 年 42 巻 4 号 p. 467-473
詳細
1989 年 42 巻 4 号 p. 467-473
The Pacific coast of Japan has often suffered severe damage by distant tsunamis propagated from the circum Pacific regions (Chile-Peru, Kurile-Kamchatka and Aleutian-Alaska). Based on the historical documents or tide-gauge records observed in Japan during the period of about 400 years, 1586-1988, the geographic distribution of cumulative tsunami energy, ∑H2 for each 150km segment along the coast is investigated. The energy distribution for the distant tsunamis is compared with that of the near tsunamis which were generated in the vicinity of Japan. The obtained results are as follows:
1) The amount of cumulative energy, ∑H2=51m2 from the Chile-Peru tsunamis is largest at the Sanriku region, northeastern Japan.
2) The tsunami energy from the Kurile-Kamchatka reaching East Hokkaido and Sanriku regions is large, but the amount of energy is about one-third of that of the Chile-Peru tsunamis.
3) The energy from the Aleutian-Alaska and Philippine-Indonesia tsunamis is relatively small because of the effect of directivity.
4) The pattern of energy distribution for the distant tsunamis is different from that for the near tsunamis generated around Japan. Percentage of the energy from the distant tsunamis reaching SW. Hokkaido, Fukushima, Ibaraki and Okinawa is about 50% of the total tsunamigenic energy.
