Earthquakes and Buildings

Earthquakes- one of the world's most devastating natural occurrences. Earthquakes have claimed lives, ruined some of the world's greatest cities, and tormented buildings and structures. Architects and designers have worked hard to create buildings which would not collapse under the violent shaking created by earthquakes. Also, studies have shown how some buildings remain intact during some of the most powerful earthquakes.
Interestingly, the 1989 Loma Prieta Earthquake in San Fransisco California, which ranked 7.1 on the Richter scale had less casualties than a 7.4 earthquake in Izmit, Turkey by a great amount. These earthquakes were close in magnitude- the main reason that the Izmit earthquake claimed more lives was because San Fransisco was more prepared for earthquakes than Izmit. Since San Fransisco is located on an active fault, architects and designers had made buildings which were able to survive earthquakes. Izmit, lacking financial funds and experience with earthquakes lost more people because the buildings were not built to survive such massive shaking. San Fransisco is home to one of the most famous buildings which has been known to survive the Loma Prieta earthquake- The Trans-America Pyramid. Apparently, the building swayed more than one foot, but miraculously, was not damaged.
All buildings vibrate at a certain frequency, when the frequency of an earthquake is too close to the frequency of the building, the most damage occurs. Normally, buildings are rocked to the point where they collapse, trapping the people inside under rubble and remains. Sometimes, neighboring buildings fall on top of each other.
Cities and towns do have specific regulations that buildings must reach to stay safe during an earthquake. In most buildings, devices that act like car-shock absorbers. These devices are used to destroy some of the effects. They absorb some of the kinetic energy produced by earthquakes and turn it into heat energy. Buildings have started to be made with stronger materials like steel and reinforced concrete, so damage is down to a minimum.
Although, earthquakes can potentially have devastating effects on buildings, changing laws and regulations may keep damage, casualties, and injuries to a minimum.

Source: http://www.science.org.au/nova/088/088key.htm