Earthquake expert and geological sciences Professor Roger Bilham of the University of Colorado at Boulder says unprecedented human fatalities from earthquakes will occur around the globe in the coming century unless significant earthquake-resistant building codes are implemented.
Bilham, who has worked extensively in the Himalaya, anticipates that the death toll from the May 12 magnitude 7.9 Sichuan Province earthquake in China may exceed 50,000 based on previous similar earthquakes in urban settings. According to May 16 reports by the Associated Press, the event damaged or destroyed 4 million apartments and homes and thousands of schools.
Bilham said there were 43 "supercities" on Earth with populations from 2 million to more than 15 million in 1950, but there are nearly 200 today. Roughly 8 million people have died globally as a result of building collapses during earthquakes in the past 1,000 years. A four-fold increase in the annual death toll from earthquakes between the 17th and 20th centuries is linked to increased urbanization, he said.
Half the world's supercities now are located near potential future magnitude 7.5 earthquakes, said Bilham, who is also a fellow of the Cooperative Institute for Research in Environmental Sciences. By the year 2025 more than 5.5 billion people will live in cities -- more than the entire 1990 combined rural and urban population. While large earthquakes over magnitude 7.5 have for the most part spared the world's major cities in the last century, this pattern will not persist indefinitely, he said.
"After the Earth Quakes," a 2006 book authored by the U.S. Geological Survey's Susan Hough and Bilham and published by Oxford University Press, looks at the collision between global urban construction and earthquake destruction. For information about his research visit the Web at cires.colorado.edu/people/bilham/.