もし東京にLittle Boyが落ちたら？

Washington Postで興味深いサイトを知りました。自分の住んでいる町に原爆が落ちたらどこまで被害が及ぶか、わかりやすくしめしてくれます。

What it would look like if the Hiroshima bomb hit your city
Maps bring the horror of Hiroshima home – literally
By Ana Swanson August 5

Alex Wellerstein, a nuclear historian at the Stevens Institute of Technology, created a NukeMap that allows you to visualize what the Hiroshima and Nagasaki explosions would look like in your hometown. Kuang Keng Kuek Ser at Public Radio International has also developed a version, using slightly different estimates.

Nuke Mapというサイトで試すことができるので、さっそく東京で試してみました。（サイトが重いので開くまで時間がかかるかもしれません。。。）

中心地を皇居に選んで、広島と長崎にそれぞれ落とされた原子爆弾を選んでやってみたのですが、率直な感想は思ったより範囲は狭いというものでした。。。不謹慎に聞こえるかもしれませんが、皇居に落とすと新宿にすら届かないんですね。

Little Boy 15kt
Fat Man 20kt

な〜んだという気持ちが起きつつあったのですが、現在の核兵器の威力を知って我に帰りました。

W-53 (Titan II warhead, highest yield in US deployed) ) 9Mt

実際に配備されているもので一番規模の大きいものだと横浜、千葉、春日部あたりまでを破壊してしまうのです。

Here is what Little Boy, the Hiroshima bomb, would look like on Wellerstein's map if detonated in Washington, D.C. An explanation of what the colors mean is below.

The effects of a nuclear bomb depend a lot on the height of the detonation. Little Boy, a 15 kiloton bomb, was detonated higher in the air, increasing the size of its effects.

As the key below shows, the area within the central yellow ring would be the maximum size of the nuclear fireball. The red ring shows the air blast radius, in which the pressure from the bomb is intense enough to severely damage or demolish heavily built concrete buildings, and fatalities approach 100 percent.

The green ring shows the radiation radius. Without medical treatment, 50 to 90 percent of people within that circle will die from the acute affects of radiationalone, either within several hours or several weeks. The gray circle shows the air blast radius, in which pressure is high enough to knock over most residential buildings. Injuries are universal and fatalities are widespread, says Wellerstein.

Finally, the yellow circle shows the thermal radiation radius. People within this circle would sustain third degree burns, which can cause severe scarring or disablement, and can require amputation.

Wellerstein says those who are out in the open would fare far worse than those inside buildings. But either way, the resulting scene would be absolutely horrific.

70年も経ったということは、それだけ核兵器も発達してしまっているという当たり前のことですが同時に恐ろしいことを気づかせてもらいました。でも正直、実感を持ってこの破壊力を把握するのは難しそうです。。。

この現在の破壊力を知ると、外交評論家Richard HaasがFinancial Timesに寄稿した主張の重要性を一層感じます。戦後70年核兵器は使用されなかったが今後70年はどうなるか不透明だという悲観的なものです。

We Will Be Lucky to Go Seventy Years Without Another Hiroshima
Author: Richard N. Haass, President, Council on Foreign Relations
August 6, 2015
Financial Times

Less commented on, though, is a question not of history but of the future: is the world likely to go another 70 years without nuclear weapons being used? The short and troubling answer is no. Even worse, the potential for such use has increased in recent years and seems likely to rise further.

国連常任理事国である国が使用する可能性は低いのですが、The greatest potential for nuclear use, though, comes from those countries that have acquired these weapons more recently.とパキスタンや北朝鮮などの最近核保有国になった国を心配しています。一番心配なのは中東だそうです。

What might be the fastest growing threat to extending the nuclear peace for another 70 years, though, comes from the Middle East.

Israel already has a substantial nuc­lear arsenal. Meanwhile, the just-negotiated agreement with Iran allows the Islamic Republic to keep most of the prerequisites of a large nuclear weapons programme, and to add to its inventory of centrifuges and supplies of enriched uranium in 10 or 15 years respectively. Other countries in the region, including Saudi Arabia, the United Arab Emirates, Turkey and Egypt, may well follow suit.

We could witness a race to establish a nuclear identity. Several governments could see value in striking first, be it to prevent an adversary developing such a capability or, amid a crisis, from actually using it. Brittle governments could lose control of weapons or materials to groups such as the Islamic State of Iraq and the Levant or al-Qaeda. And terrorists could marry nuclear materials to conventional explosives and cause widespread panic and harm, even without detonating a nuclear explosion.

だからといって過剰反応はいけないのかもしれませんが、当時と事情が変わってきていることは確かなようです。