伊豆大島災害 なぜ避難を促さなかったのか

The Yomiuri Shimbun October 19, 2013
Why was no evacuation order issued in Izu Oshima downpours?
伊豆大島災害　なぜ避難を促さなかったのか（10月18日付・読売社説）

Were there no means of preventing a major calamity from occurring?
　大惨事を防ぐ手だてはなかったのか。

Because of the extremely heavy rain that accompanied Typhoon No. 26, several communities on Tokyo’s Izu Oshima island were hit by debris flows. The disaster claimed the lives of 22 people and left many missing. The Metropolitan Police Department and other organizations concerned must do their utmost to locate and rescue the missing.
　台風２６号に伴う豪雨で伊豆大島の集落が土石流に襲われた。死者２２人、行方不明者も多数に上っている。警視庁などは不明者の救出に全力を挙げてほしい。

On Tuesday evening, when the typhoon—reported to be the strongest in the last 10 years—was moving north toward the Japanese archipelago, the Japan Meteorological Agency issued heavy rain and mudslide alerts to the Oshima town government on Izu Oshima island.
　１０年に１度とされる強い台風が日本の南海上を北上中の１５日夕、気象庁は大雨警報と土砂災害警戒情報を東京都大島町に出した。

The alerts, which call for caution regarding mudslides, are considered key information for municipalities involved to use for reference in issuing evacuation advisories or orders, but the Oshima Island municipal authorities issued neither.
　土砂災害警戒情報は市町村が避難勧告や避難指示を発令する際の参考情報と位置付けられるが、町は発令しなかった。

The town mayor explained the lack of action was because an evacuation advisory could “lead to an increased number of people exposed to the threat of strong rain at night.”
「夜間で大雨の中、被害者を増やす恐れがあった」というのが町長の説明だ。

The rainfall on the island increased sharply shortly after midnight Tuesday. Precipitation in the three hours before dawn on Wednesday reached the second-highest levels in the recorded history of domestic weather. The mudslides occurred around the same time.
　雨量は１６日午前０時過ぎから急増した。未明の３時間雨量は国内統計史上２番目の数値を観測し、その頃、土石流が発生した。

Any attempt to evacuate residents in the midst of the violent storm would certainly have been difficult. However, was it impossible for municipal authorities to warn people to get out of danger the previous day when the meteorological agency issued the alerts?
　確かに、暴風雨の中での避難は難しかったろう。だが、警戒情報が出た前日のうちに避難を呼びかけることはできなかったのか。

Given that typhoon’s paths are predictable to some extent, there can be lead time to evacuate, unlike such events as tsunami or tornadoes. The town authorities should have taken adequate precautions by recognizing the danger earlier.
　進路予想がある程度正確な台風の場合、津波や竜巻などに比べて事前の避難には時間的余裕があるだろう。町は危険を察知し、適切な対応を取るべきだった。

Beware of localized disaster

It is possible that the town’s decision-making process was hindered by the fact that both the mayor and deputy mayor of the town were away from the island on a business trip when the typhoon hit.
　町長と副町長が出張で不在だったことが、町の意思決定に影響を及ぼした可能性もある。

On Izu Oshima island, there have been many debris flows, including those in the 1958 Kanogawa Typhoon, in which 18 people were killed or injured and 104 houses were destroyed or damaged. It is highly regrettable the lessons of the past calamities failed to be used effectively in the latest disaster to hit the island.
　伊豆大島では、１９５８年の狩野川台風で１０４棟が全半壊し、１８人が死傷するなど、度々、土石流が発生している。過去の教訓が生かされなかったのは残念だ。

The meteorological agency, for its part, came short of issuing a special warning recently introduced for the purpose of calling for vigilance against the highest level of danger due to rainfall. That was because the rainfall on the island did not meet the requirements for issuing the warning that requires threshold-level precipitation across an extensive area, or an area encompassing most of a prefecture.
　気象庁は今回、最大級の危険に対して警戒を呼びかけるために導入した特別警報を発しなかった。府県のほぼ全域など、広い範囲で危険が迫っているという基準を満たさなかったからだ。

Based on this criteria, there can be many cases in which a disaster on a remote island may be excluded from the special warnings. Studies must be done to review the standards of how a similar level of warning could be issued against localized dangers.
　この基準では、離島の災害は特別警報の対象から外れるケースが多くなる。局所的な危険に対し、同レベルの注意喚起ができるよう基準の見直しを検討すべきだ。

Under the law for the prevention of sediment-related, each prefectural government is supposed to designate danger areas as caution zones. When the designation is made, city, town and village governments concerned are obliged to create and make public hazard maps.
　土砂災害防止法上、都道府県は危険地域を警戒区域などに指定することになっている。指定されると、市町村は避難場所などを明示したハザードマップを作成・公表する責任を負う。

The Tokyo metropolitan government, however, has yet to embark on procedures to apply the disaster-prone area designation to islands under its jurisdiction, while the town government of Oshima has failed to make any hazard map covering mudslides.
　しかし、都は島嶼(とうしょ)部での指定に着手しておらず、大島町は土砂災害を想定したハザードマップを作成していなかった。

Designation of caution zones has been delayed nationwide, for reasons including opposition from local residents who worry that such a designation would reduce the value of their homes. Every municipality must redouble their efforts to secure residents’ understanding of the need for the designation.
　警戒区域などの指定は全国的にも遅れている。「指定されると不動産価値が下がる」といった住民の反対などが背景にある。各自治体は住民の理解を得るよう努めなければならない。

The calamity on Izu Oshima island should be taken as a warning by everyone living in the nation, which is highly susceptible to disasters.
　伊豆大島の惨事は、災害列島に暮らす国民への警鐘でもある。

(From The Yomiuri Shimbun, Oct. 18, 2013)
（2013年10月18日01時32分 読売新聞）