So let's begin with how we measured wave speed I was surprised how straightforward that was.

我们从测量波速开始吧，这个简单得让我有点惊讶。

Each earthquake pair happened in the same place but at different times, allowing the researchers to measure how much the sound waves sped up.

每对地震都发生在相同的地方，但发生的时间不同，这使得研究人员能够测量声波加速了多少。

Multiply the wavelength by the frequency, and you get the wave's speed -- how fast it's going.

将波长乘以频率， 你得到了波的速度。

Multiply the wavelength by the frequency, and you get the wave’s speed -- how fast it's going.

将波长乘以频率， 就可以得到波的速度——它的速度有多快。

In fact, as long as the water is deeper than the wave base, wave speed is inversely proportional to its frequency.

事实上， 只要水比波底深，波速就与其频率成反比。

You might remember when we talked about traveling waves that a wave's speed is equal to its frequency times its wavelength.

你可能还记得当我们谈到行波时，波的速度等于它的频率乘以波长。

But there was a problem with this idea: Two boats will measure an ocean wave's speed differently depending on their own velocities through the water.

但是这个想法有一个问题：两艘船将根据它们自己在水中的速度来测量海浪的速度。