What makes surface waves so destructive

They travel only along the surface of the Earth. There are two types of surface waves: Love and Rayleigh waves. Rayleigh waves cause both vertical and horizontal ground motion. These can be the most destructive waves as they roll along lifting and dropping the ground as they pass. Want to learn more about earthquakes? Check out this video about how engineers use a giant shaking table to design earthquake safe structures.

Building envelope Strengthening strategies Non-structural systems. Seismic science and site influences Resilient design Superstructure Foundations Building envelope Strengthening strategies Non-structural systems.

Resources About Contact Disclaimer and copyright. Acknowledgements Privacy statement References Glossary. Earthquakes - Each year many people are killed during the collapse of buildings caused by the shaking associated with earthquakes. Of the million inhabitants asleep in the city, , lost their lives in buildings that collapsed.

When walls collapsed, the roofs caved in, and the sleeping inhabitants were crushed. In the United States the San Francisco earthquake is the most famous. Elastic rebound - The earth is an elastic body which can be strained during plate tectonic processes. In particular, fault zones at the boundaries of large lithospheric plates lock despite the motion of the plates. Over time large strains can accumulate in rocks next to the fault zone. Finally, stresses become so large at the locked fault zones rupture and slip.

This rapid slippage releases the strain energy which was accumulated over a long period of time in a process called elastic rebound. As the fault zone slips seismic waves are released. Seismic waves - There are two groups of earthquake waves called body waves and surface waves.

Body waves travel from the earthquake focus in all directions whereas surface waves travel around the earth rather than through it. Imagine that you have your Slinky on its side on a table. With one person holding each end, push your end forward and pull back. This is how P waves travel through the earth, moving it back and forth. An earthquake also causes secondary or shear waves, called S waves. These travel at about half the speed of P waves, but can be much more destructive.

S waves move the earth perpendicularly to the direction the wave is traveling. Picking up the Slinky again, move it left and right, rather than forward and back. Now move the end of the Slinky up and down, watch the S waves travel, and imagine how a building would fare sitting atop the action.