Tsunamis – Lump in the Ocean

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ambience: ocean

All ocean waves are not created equal. There’s a crucial difference, for example, between tsunamis and tidal waves. I’m Jim Metzner, and this is the Pulse of the Planet.

“A tsunami is when the surface of the ocean is-is changed in shape over a very large area, and it produces a succession of waves.”

Gerard Fryer is an associate Geophysicist and Tsunami Researcher at the University of Hawaii.

“You can imagine if you have an extra lump of water at the ocean surface that’s, say, 100 miles wide, that lump will collapse and oscillate, and every time it oscillates, it’s going to send waves out. And the entire sequence of waves is a tsunami. Now, how it differs from ordinary waves in the ocean is the wavelength, the distance from one wave to the next, or, if you prefer, the time from one wave to the next. In this last tsunami in the Indian Ocean the waves were 45 minutes apart. The average surfing wave in the north shore of Oahu in Hawaii, those waves are about 22 seconds apart, and that’s regarded as very long. So, you can see that there’s a huge difference in the scale of these things.

What about tidal waves?

“A tidal wave is a wave that is generated by tides, by the sun and the moon pulling on the ocean, and this rising water is channeled into a river mouth or something and eventually forms vertical wall of water, that-that comes up the river or comes into a bay. And the reason that tsunamis are often called tidal waves is because, if you’re looking at it, a tsunami may look identical to a true tidal wave. The term tidal wave is very dangerous. It implies that there’s only one wave, and the important thing to know about a tsunami is that there’s more than one wave. ”

In future programs we’ll hear what causes tsunamis. Pulse of the Planet is presented by the National Science Foundation. I’m Jim Metzner.

music

Tsunamis - Lump in the Ocean

There's a crucial difference between tsunamis and tidal waves.
Air Date:08/13/2008
Scientist:
Transcript:

music
ambience: ocean

All ocean waves are not created equal. There's a crucial difference, for example, between tsunamis and tidal waves. I'm Jim Metzner, and this is the Pulse of the Planet.

"A tsunami is when the surface of the ocean is-is changed in shape over a very large area, and it produces a succession of waves."

Gerard Fryer is an associate Geophysicist and Tsunami Researcher at the University of Hawaii.

"You can imagine if you have an extra lump of water at the ocean surface that's, say, 100 miles wide, that lump will collapse and oscillate, and every time it oscillates, it's going to send waves out. And the entire sequence of waves is a tsunami. Now, how it differs from ordinary waves in the ocean is the wavelength, the distance from one wave to the next, or, if you prefer, the time from one wave to the next. In this last tsunami in the Indian Ocean the waves were 45 minutes apart. The average surfing wave in the north shore of Oahu in Hawaii, those waves are about 22 seconds apart, and that's regarded as very long. So, you can see that there's a huge difference in the scale of these things.

What about tidal waves?

"A tidal wave is a wave that is generated by tides, by the sun and the moon pulling on the ocean, and this rising water is channeled into a river mouth or something and eventually forms vertical wall of water, that-that comes up the river or comes into a bay. And the reason that tsunamis are often called tidal waves is because, if you're looking at it, a tsunami may look identical to a true tidal wave. The term tidal wave is very dangerous. It implies that there's only one wave, and the important thing to know about a tsunami is that there's more than one wave. "

In future programs we'll hear what causes tsunamis. Pulse of the Planet is presented by the National Science Foundation. I'm Jim Metzner.

music