It was once said that the casualties in an earthquake were not caused by the earthquake itself, but by the buildings. After the Wenchuan earthquake in Sichuan, we also saw shocking pictures: a large number of houses collapsed, people were buried under the ruins, especially many school teaching buildings turned into rubble. People can't help asking, is it unavoidable that walls and houses collapse in an earthquake? German experts said that if the buildings were built according to the seismic standards, even if they were damaged, they absolutely should not collapse. School buildings should be the strongest.