B2 中上級 20983 タグ追加 保存
動画の字幕をクリックしてすぐ単語の意味を調べられます!
単語帳読み込み中…
字幕の修正報告
In 479 BC, when Persian soldiers be seiged
the Greek city of Potidaea,
the tide retreated much farther than usual,
leaving a convenient invasion route.
But this wasn't a stroke of luck.
Before they had crossed halfway,
the water returned in a wave higher
than anyone had ever seen,
drowning the attackers.
The Potiidaeans believed they had been saved
by the wrath of Poseidon.
But what really saved them was likely
the same phenomenon that has destroyed countless others:
a tsunami.
Although tsunamis are commonly known as tidal waves,
they're actually unrelated to the tidal activity caused
by the gravitational forces of the sun and moon.
In many ways, tsunamis are just larger versions
of regular waves.
They have a trough and a crest,
and consist not of moving water,
but the movement of energy through water.
The difference is in where this energy comes from.
For normal ocean waves,
it comes from wind.
Because this only affects the surface,
the waves are limited in size and speed.
But tsunamis are caused by energy
originating underwater,
from a volcanic eruption,
a submarine landslide,
or most commonly,
an earthquake on the ocean floor
caused when the tectonic plates of the Earth's surface slip,
releasing a massive amount of energy into the water.
This energy travels up to the surface,
displacing water and raising it above
the normal sea level,
but gravity pulls it back down,
which makes the energy ripple outwards horizontally.
Thus, the tsunami is born,
moving at over 500 miles per hour.
When it's far from shore,
a tsunami can be barely detectable
since it moves through the entire depth of the water.
But when it reaches shallow water,
something called wave shoaling occurs.
Because there is less water to move through,
this still massive amount of energy is compressed.
The wave's speed slows down,
while its height rises to as much as 100 feet.
The word tsunami,
Japanese for "harbor wave,"
comes from the fact that it only seems to appear
near the coast.
If the trough of a tsunami reaches shore first,
the water will withdraw farther than normal
before the wave hits, which can be misleadingly dangerous.
A tsunami will not only drown people near the coast,
but level buildings and trees for a mile inland or more,
especially in low-lying areas.
As if that weren't enough,
the water then retreats,
dragging with it the newly created debris,
and anything, or anyone, unfortunate enough
to be caught in its path.
The 2004 Indian Ocean tsunami
was one of the deadliest natural disasters in history,
killing over 200,000 people throughout South Asia.
So how can we protect ourselves
against this destructive force of nature?
People in some areas have attempted
to stop tsunamis with sea walls, flood gates,
and channels to divert the water.
But these are not always effective.
In 2011, a tsunami surpassed the flood wall
protecting Japan's Fukushima Power Plant,
causing a nuclear disaster in addition to claiming
over 18,000 lives.
Many scientists and policy makers are instead
focusing on early detection,
monitoring underwater pressure and seismic activity,
and establishing global communication networks
for quickly distributing alerts.
When nature is too powerful to stop,
the safest course is to get out of its way.
コツ:単語をクリックしてすぐ意味を調べられます!

読み込み中…

読み込み中…

【TED-Ed】津波ってどう起きるの?(How tsunamis work - Alex Gendler)

20983 タグ追加 保存
Zenn 2014 年 6 月 14 日 に公開    Hoshie Go 翻訳    Kana kawai チェック
お勧め動画
  1. 1. クリック一つで単語を検索

    右側のスプリクトの単語をクリックするだけで即座に意味が検索できます。

  2. 2. リピート機能

    クリックするだけで同じフレーズを何回もリピート可能!

  3. 3. ショートカット

    キーボードショートカットを使うことによって勉強の効率を上げることが出来ます。

  4. 4. 字幕の表示/非表示

    日・英のボタンをクリックすることで自由に字幕のオンオフを切り替えられます。

  5. 5. 動画をブログ等でシェア

    コードを貼り付けてVoiceTubeの動画再生プレーヤーをブログ等でシェアすることが出来ます!

  6. 6. 全画面再生

    左側の矢印をクリックすることで全画面で再生できるようになります。

  1. クイズ付き動画

    リスニングクイズに挑戦!

  1. クリックしてメモを表示

  1. UrbanDictionary 俚語字典整合查詢。一般字典查詢不到你滿意的解譯,不妨使用「俚語字典」,或許會讓你有滿意的答案喔