Mon Prof Augmenté
Sensors on the Seabed
Instruments resting on the ocean floor feel the pressure and the shaking of a large earthquake. A buoy carries that signal upward so coastal towns can be warned before the water arrives.
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Age 14: open this week
Browse Age 14
In the picture
- A pressure sensor on the seabed: it records the weight of the water above it and any sudden change
- A surface buoy: it floats above the sensor and sends the reading onward through the air
- A satellite: it receives the signal from the buoy and passes it to scientists on land
- A coastal town: streets and a stairway climbing uphill away from the shoreline
Examples
- A tide gauge in a harbour that logs the water height every few minutes.
- A weather station on a roof that measures wind speed and sends it to a phone app.
Key takeaways
- In deep water a tsunami wave is small at the surface but changes pressure strongly down at the seabed.
- Warning time depends on how much faster the signal travels than the wave itself.
Carry on in the app
Three questions on this lesson. It has left the free week, so its quiz is for subscribers.
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