DESIGN AND CRITERIA LOADS
Marshall Lew and Farzad Naeim
Strong ground shaking presents the greatest hazard to property and personal safety in the urban habitat in the seismically active regions of the world. However, there are geologic and seismic hazards that threaten a smaller population in the urban habitat. These hazards include the effects of surface fault rupture, liquefaction, and landsliding. With proper precautions, the exposure to these hazards could be avoidable.
As the world population continues to grow at an ever-increasing rate, the teeming masses of many major metropolitan cities are swelling at an even greater rate. Many of these cities, such as Tokyo, Auckland, Mexico City, Manila, Santiago, Los Angeles, San Francisco, Athens, Istanbul, Tehran, and Vancouver, are located along or near the boundaries of major tectonic plates where damaging earthquakes have already been experienced or are expected to occur. However, rapid urbanisation and unchecked growth of many of these cities and surrounding areas have proceeded without considering or exploring the geologic and seismic hazards that may exist beyond the ground shaking.
Recent earthquakes occurring through the end of the last millennium illustrate that the recognition of geologic and seismic hazards in the urban habitat is still not a reality, even in the most technologically advanced countries of the world. However, bold attempts are being made in some jurisdictions to identify land areas where such hazards may exist and to require that the public be informed about the inherent risks of occupying and ownership of properties within such areas. Such efforts are not without opposition, as such important issues as maintaining economic value and use of property are weighed versus public safety.