homework
This is Scientific American's 60-Second Science. I'm Cynthia Graber. This will just take a minute.
In an earthquake, the ground beneath you gives away. It’s no longer the one thing you can count down to be solid and stable. Instead it’s swerves dips and waves. And now scientists are saying that earthquakes can cause the ground to do something they didn’t expect, to bounce up and down like a /.
Scientists of Japan’s national institute for earth science and disaster prevention analyzed information from a recent quake in their country. They noticed that the ground jolted around in a way that couldn’t be explained with traditional models. They reported their findings in the October 31 issue of the Journal Science.
According to common models, earthquakes are expected to ripple horizontally and the resulting up and down waves should be symmetrical. The June quake had been rapidly accelerating up and down movement with asymmetrical waves and much higher peaks. The researchers propose a new model of how the soil is behaving.
They say the lighter soil was bouncing off the top crust beneath you. Understanding how this process works is important for the architects and engineers who design bridges and buildings to withstand an earthquake’s shake.
Thanks for the minute for Scientific American's 60-Second Science. I'm Cynthia Graber. |