Even though it wasn’t the “big one,” last year’s Nisqually earthquake caused damage to nearly 300,000 residences or almost one out every four households in the Puget Sound area, according to a new UW study. The study, funded by the National Science Foundation, shows that the Feb. 28, 2001, quake caused an estimated $1.5 billion in damages to households in the region.
The findings also indicate that the vast majority of residents have made little effort to change their earthquake preparedness following the temblor that registered magnitude 6.8.
The study is the first to focus strictly on household damages from the earthquake. Previous estimates of damage, ranging from $2 billion to $3.9 billion, combined losses to public, business and household property.
Results of the study were reported over the weekend at the North American Regional Science Meetings in San Juan, Puerto Rico, by UW geography professor William Beyers, who studies economic geography. Co-investigator of the study is Stephanie Chang, a UW research assistant professor of geography, who looks at the impacts of natural disasters.
The study was based on 1,200 telephone interviews, with 400 interviews conducted in each of three ground motion zones. Losses, the study showed, were not always proportional to levels of ground motion — high, medium and low — created by the earthquake across the Puget Sound region.
While the percentage of households reporting losses was directly proportional to ground motion, average damages were almost identical in the high and medium ground motion zones. Average losses in the high ground motion zone were $1,350, while they were $1,308 in the medium ground motion zone. Household damages in the low ground motion zone averaged $622.
However, in absolute dollars, damage was greatest in the medium ground motion zone where $913 million of the damage occurred. That’s because nearly 60 percent of Puget Sound households are located in these areas, according to Beyers.
The researchers also found that:
- Repairs of about $800 million were primarily paid for out-of-pocket and to a lesser extent by grants from the Federal Emergency Management Agency.
- About $700 million in household damages were not repaired.
- Structural damages to roofs, walls or foundations were the most common loss, accounting for $922 million, followed by chimney damage ($198 million); damages to non-structural elements such as windows and light fixtures ($108 million); damages to property around a residence such as driveways and fences ($80 million); and damages to household contents ($76 million).
- Overall only 26 percent of those whose homes sustained damage chose to make repairs, but those who suffered larger losses were more likely to fix damages. Only 8 percent suffering losses under $100 said they made repairs, compared to 88 percent who had loses ranging from $10,000 to $20,000.
Prior to the Nisqually quake less than half the households had taken steps to prepare for an earthquake such as obtaining first-aid training, making emergency plans and securing items in the house. Even after the quake Beyers and Chang found that about four out of five households did not change their earthquake preparedness.
“The quake wasn’t a big enough disaster to scare most people into doing something to mitigate future damage,” said Beyers. “A lot of people said, ‘We did fine in the earthquake so we don’t need to change the way we did things.’ The bigger the loss, the more apt people were to do something, but relatively few people were really hit hard.”
Public agencies wishing to promote earthquake preparedness and damage reduction need to reach the public through a wide variety of media, Beyers said, because people obtained information from an enormous variety of sources.
Newspapers and television news programs were the most common primary sources, but were only cited by 22 and 20 percent, respectively. Other sources mentioned included friends and relatives; materials distributed by employers, Red Cross and the fire department; previous earthquake experience in California; radio; the Internet; and pamphlets in the mail.