连接:海啸警报系统

A tsunami (Japanese for "harbor wave") is the name given a very large, very fast wave that strikes the coast. These waves are rare, but can be caused by an earthquake, a volcanic eruption, or an asteroid crashing into the ocean. About 90% of all tsunamis occur in the Pacific Ocean.
::海啸(日语为“harbor wave ” ) 是一个称为“harbor wave ” ( harbor world ) 的命名。 海啸是冲击海岸的非常大、非常快的波浪。 这些波浪是罕见的,但可能是地震、火山爆发或小行星坠入海洋造成的。 大约90%的海啸发生在太平洋。

The most common cause of a tsunami is an underwater earthquake. Not all earthquakes cause tsunamis, however—only those greater than 6.75 on the Richter Scale. Because tsunamis can be so devastating, it is important to be able to predict whether a tsunami is likely to occur (that is, whether an earthquake has a magnitude greater than 6.75) and how much time people on the nearby  coast have to evacuate to avoid the destruction.
::海啸最常见的起因是水下地震。 并非所有地震都引发海啸,但只有里氏6.75级的地震才会引发海啸。 由于海啸可能具有毁灭性,因此必须能够预测海啸是否可能发生(即地震规模是否大于6.75级)以及附近沿岸人们为避免破坏而需要撤离多少时间。

To predict evacuation times, the National Oceanic and Atmospheric Administration (NOAA) calculates the speed of the tsunami. A s long as we know the depth of the ocean where the earthquake occurred, $\begin{array}{r}H\end{array}$ , we can calculate the tsunami's speed using the formula $\begin{array}{r}c=\sqrt{gH}\end{array}$ , where $\begin{array}{r}g\end{array}$  is acceleration due to gravity (a constant; $\begin{array}{r}g=\end{array}$ 9.8 m/s ² ). As the tsunami gets closer and closer to the coast, it grows in amplitude, so it is critical to give people living on and visiting the coast as much time as possible to evacuate. The faster the tsunami, the less time for evacuation; conversely, the slower the tsunami, the longer time for evacuation ¹ .
::为了预测疏散时间,国家海洋和大气管理局(海洋大气管理局)计算了海啸的速度。只要我们知道地震发生地的海洋深度,H,我们就可以使用公式c=gH来计算海啸的速度,G是重力加速(恒定值;g=9.8m/s2),而G是重力加速度(恒定值;g=9.8m/s2),当海啸越来越接近海岸时,它会变大,因此让生活在和访问海岸的人有尽可能多的时间撤离至关重要。海啸越快,疏散时间就越少;反过来,海啸越慢,疏散时间就越长。1

1. Find the speed of a tsunami if the depth of the earthquake is 50 meters, 200 meters, 2,000 meters, and 4,000 meters. 
::1. 如果地震深度为50米、200米、2 000米和4 000米,则寻找海啸的速度。

2. Graph the function. 
::2. 绘制函数图。

3. Convert the speeds to miles per hour (1 m/s = 2.24 mph).
::3. 将速度转换为每小时英里(1 m/s = 2.24 mph)。

4. NOAA has a system of buoys off the western coast of the U.S. to detect seismic activity. How long would the system have to notify people if the earthquake was 400 miles offshore and the depth of the earthquake was 2,000 meters? What if it were only 100 miles away?
::4. 诺阿在美国西海岸有一套探测地震活动的浮标系统,如果地震离岸400英里,地震深度2 000米,该系统需要通知人们多久?如果只有100英里远,那又如何?

5. Tsunami waves often become higher as they approach the shore. The formula we can use to determine wave height is  $\begin{array}{r}\frac{s}{d}=(\frac{D}{S}{)}^{\frac{1}{4}},\end{array}$  where s and  d are the wave heights in shallow and deep waters, respectively, and S and  D are the depths of the shallow and deep waters, respectively. What would be the wave height of a tsunami wave that is 2 meters high, at a depth of 4,000 meters in the ocean, when it reaches land at a depth of 10 meters? 
::5. 海啸波在接近海岸时往往会高一些,我们可以用来确定海浪高度的公式是 sd=(DS)14, 浅水和深水的海浪高度分别为 s和 d, 浅水和深水的海浪高度分别为S 和 D, 浅水和深水的深度分别为2米高,海深4 000米,到达10米深的陆地的海浪高度是多少?

by NOAA explains the basics of tsunamis and how to protect yourself. 

::诺阿解释海啸的基本原理以及如何保护自己。

References
::参考参考资料

1. "NOAA Tsunami Website,"  
::1. 诺阿海啸网站,