Insured losses from Christchurch quake could reach $8 billion: AIR

Insured losses from the Feb. 22 earthquake in Christchurch, New Zealand will likely range from $3.5 billion and $8 billion, AIR Worldwide reported.
Experts warn similar factors that contributed to the massive damage in Christchurch also exist in British Columbia cities and along the U.S. West Coast.
“Christchurch is New Zealand’s second-largest city, and while design requirements for new construction are stringent, many historical buildings dominate the central business district, and they are predominately of masonry construct,” said Dr. Arash Nasseri, an engineer at AIR Worldwide.
“Few have undergone seismic retrofit. Structures may also have been weakened by the magnitude 7.0 earthquake that took place in early September of last year.”
The Feb. 22 quake occurred at a shallow distance of five kilometres below the earth’s surface and shook sediments prone to liquefaction, compounding damage to the city’s infrastructure and buildings. Liquefaction causes soil to lose its strength and stiffness in response to an applied stress, usually earthquake tremors, and causes the soil to behave like a liquid.
Robert Yeats, a professor of geology at Oregon State University, said the characteristics of the deadly Christchurch quake match those of cities in British Columbia, and along the West Coast of the United States. Risks from comparatively shallow ‘crustal’ faults are often given less attention compared to major subduction zones in the Pacific Northwest, or famous plate boundaries, such as the San Andreas Fault.
“The latest New Zealand earthquake hit an area that wasn’t even known to have a fault prior to last September – it’s one that had not moved in thousands of years,” Yeats told Asian News International. “But when you combine the shallow depth, proximity to a major city and soil characteristics, it was capable of immense damage.”