社説：南海トラフ津波 想定受け止め対策を

(Mainichi Japan) April 3, 2012
Editorial: Catastrophic quake, tsunami projections demand policy rethink
社説：南海トラフ津波　想定受け止め対策を

If a major earthquake hits the "Nankai Trough" off central and western Japan's Pacific coast, the resulting tsunami could tower two to three times higher than previously estimated, according to an expert government panel announcement on March 31.
　これまで想定された２～３倍の津波高が公表された。西日本の太平洋沖に延びる「南海トラフ」で発生が懸念される巨大地震に伴うものだ。

The panel assumed a magnitude-9.1 temblor -- close to the same strength as the Great East Japan Earthquake of March last year -- and put together maximum damage estimates based on the latest scientific data.
　内閣府の有識者検討会が、地震の規模を示すマグニチュード（Ｍ）を東日本大震災なみの９・１に設定し、最新の科学的知見に基づき、考えられる最大級の被害を試算した。

The result: a quake measuring a high-6 on the Japanese 7-point intensity scale and destruction to 395 municipalities in 21 prefectures -- more than five times greater than was projected in a 2003 study. Moreover, if the quake hit at high-tide, the resulting tsunami would top 20 meters when they slammed into 23 municipalities in the Tokyo islands and Shizuoka, Aichi, Mie, Tokushima and Kochi prefectures. The largest projected wave, at 34.4 meters high, would hit the town of Kuroshio, Kochi Prefecture.
　震度６強以上は２１府県３９５市町村で、０３年に被害想定した際の５倍以上に拡大した。また、満潮時の津波高は、東京の島しょ部や静岡、愛知、三重、徳島、高知の６都県２３市町村で２０メートルを超えると予測した。最大は３４・４メートルの高知県黒潮町だ。

Of especially serious note in the estimates is the maximum 21-meter-high tsunami projected for Chubu Electric Power Co.'s Hamaoka nuclear power plant in Omaezaki, Shizuoka Prefecture. After the meltdowns at the Fukushima No. 1 nuclear plant -- triggered when backup generators powering the reactors' cooling systems were flooded by tsunami -- Chubu Electric began building an 18-meter-tall, 1.6-kilometer-long tsunami breakwater to guard the Hamaoka plant.
　深刻なのは、中部電力浜岡原発が最大２１メートルの津波に襲われる可能性が指摘されたことだ。東京電力福島第１原発事故を受けて、中部電は緊急安全対策の一環で高さ（海抜）１８メートル、長さ１・６キロの防波壁を年内完成を目指して建設中である。

The projected tsunami, however, would get over the barrier and swamp the station. Obviously, Chubu Electric's tsunami countermeasures need a drastic rethink.
　だが、想定に従えば津波は防波壁を越え、浸水は原発敷地にまで及ぶ。当然のことながら、津波対策を含めた抜本的な見直しが必要だ。

Then there are the tsunami estimates for major urban centers. A wave over 20 meters high is projected for Toyohashi, Aichi Prefecture, and waves over 10 meters for the cities of Shizuoka, Hamamatsu, Kochi and Miyazaki.
　注目されるのは、人口が多い都市部でも相当な津波高が予想されることだ。愛知県豊橋市は２０メートルを超え、静岡、浜松、高知、宮崎の各市でも１０メートルを超える地点がある。

Starting this month, the expert panel will begin releasing flood projections based on the estimated tsunami heights. Meanwhile, the Cabinet Office's Central Disaster Prevention Council is scheduled to announce total damage projections, including the number of dead and total buildings destroyed, in June this year.
　検討会は４月以後、津波高予測に基づく浸水想定区域を公表する。中央防災会議も死者数や全壊棟数など被害想定を６月に公表予定だ。

The foundation of any anti-tsunami damage policy must be the lessons learned from the experience of last year's terrible waves, which took the lives of many who could not flee in time. Municipalities along Japan's Pacific coast, menaced by three projected catastrophic quakes -- Tokai, Tonankai and Nankai -- along the Nankai Trough, must formulate such policies especially quickly.
　津波対策は、避難の遅れから多数の被害者が出た東日本大震災の教訓をどう生かすのかが基本だ。南海トラフを震源域とする東海、東南海、南海地震が想定される太平洋側の市町村は、特に対策が急がれる。

An expert investigative committee under the disaster prevention council concluded last year that communities should be built such that anyone could walk to safety within about five minutes in case of a tsunami. However, the latest estimates warn of one-meter tsunami hitting the coast in about 2 minutes after a major quake. There are some local governments that have taken concrete tsunami safety measures, such as designating tall buildings as evacuation sites, building evacuation towers and demarking evacuation routes to high ground. In light of the new estimates, however, a re-evaluation of these measures -- including minimum evacuation times -- is required.
　中央防災会議の専門調査会は昨年、津波が発生した場合、原則として歩いて５分程度で安全な場所に避難できるまちづくりを提言した。だが、今回の想定では高さ１メートルの津波が最短２分で到達する。津波避難ビルの新たな指定や津波避難タワー建設、高台への避難路確保など具体的に動き出した地域もあるが、避難時間も含め見直しを迫られよう。

Finally, the state's financial support cannot be ignored. The government is set to draw up measures to deal with current difficulties this summer. What's essential, however, is that the central, prefectural and municipal governments build a unified policy on this issue. We call for deep discussion on what should be given priority in building such policy.
　最終的には、国の財政面での支援が欠かせない。国は今夏にも当面実施すべき対策をまとめるが、重要なのは国と都道府県、さらには市町村が一体的に対応することだ。どう優先度をつけて対策を進めるのか、互いに議論を深めてほしい。

Furthermore, the countermeasures laid out in the special measures law for the projected Tokai earthquake are different than those for Tonankai or Nankai quakes. Prefectural governors and other people in the areas likely to be affected, however, have begun calling for a united countermeasures law. If changes in the law are required, then the central government should get working on them as soon as possible.
　また、東南海・南海地震と、予知を前提とした東海地震では、対策を規定した特別措置法の内容が異なっている。しかし、広域での避難や減災対策が求められる現状では、一本化が望ましいとの声が知事会議などから出ている。必要な法改正ならば、国は早急に取り組むべきだ。

毎日新聞　2012年4月3日　東京朝刊