Major earthquakes probably will kill fewer people and wreak greater economic damage than previously estimated, according to a new analysis released this week.
"In studies done earlier, the numbers didn't match with what was happening," said Haresh Shah, a Stanford University civil engineering professor and the study's chief author. "Every time there was an earthquake, fatalities were a lot smaller than numbers that were coming out, and our economic loss was a lot bigger."Shah's study includes the lessons from the 1989 Loma Prieta earthquake in the San Francisco Bay area as well as the 6.7-magnitude Northridge quake in January, which killed 61 people and caused an estimated $20 billion in damage.
Working with Risk Management Solutions Inc. of Palo Alto, he used computer modeling to estimate worst-possible cases for major quakes in heavily developed areas, and calculated damages based on actual property values in 1994 dollars.
Their more comprehensive estimates of economic losses place greater weight on workers' compensation losses, business interruption losses and other ripple effects of businesses being forced to close.
Among the conclusions:
- A magnitude 7 earthquake on Los Angeles' Newport-Inglewood fault could kill as many as 5,000 people and leave another 5,000 to 15,000 seriously injured. The economic loss could be as high as $145 billion.
In 1981, the Federal Emergency Management Agency projected that a stronger, magnitude 7.5 quake on the same fault would leave up to 23,000 dead, 91,000 hospitalized and cause $69 billion in losses.
- An 8.3-magnitude quake in San Francisco, like the deadly 1906 temblor, could result in as many as 6,000 deaths and 20,000 serious injuries and leave up to $135 billion damage in its wake.
FEMA projected 11,000 deaths, 44,000 injuries and $38 billion in losses.
- A 7.9-magnitude quake in Tokyo, equal to the force of the Great Kanto Earthquake of 1923 that killed 140,000 people, would be far worse than the California events. It could leave 60,000 dead, 100,000 injured and as much as $1.2 trillion in economic loss.
A quake of magnitude 2.5 to 3 is the smallest generally felt by people. Magnitude 7 indicates a major earthquake capable of widespread, heavy damage. Magnitude 8 is a "great" earthquake capable of tremendous damage.
Tom Mullins, spokesman for the California Office of Emergency Services, said that no matter what studies show, "People do need to be prepared. Whatever the projected numbers may or may not be doesn't change that fact."