P waves typically cause windows to rattle and feel like a truck bumping a building. There are also two types of surface waves, which tend to arrive last. In spite of this, the buildings can still be heavily damaged and may not be able to be used for days, weeks, or months after the earthquake. Older housing can be retrofitted to be more earthquake resistant. Some examples of problem homes and resistent homes and apartments are provided in the slide shows in the mitigation section of our site.
Technology is extremely important in the way our buildings and other structures are designed.
The structural engineering community learns from earthquakes and corrects building and structure design to take into account those new lessons. Thus, our new highway bridges and interchanges are not built the same way they were 50 years ago - or even 20 years ago. Throughout this process, we use computer technology to model shaking and other hazards, as well as to test how revised designs will withstand shaking. Thus, the 1964 Alaska earthquake trigged a tsunami that flooded and heavily damaged coastal northern California near Cresent City. The Exploratorium's Earthquake site is also wonderful.