Saturday, December 03, 2016

An earthquake worse than the big one? Shattered New Zealand city shows danger of Seattle's fault

[Seattle Times] The nine people on Red Bus No. 702 were going separate ways on a Tuesday afternoon: to lunch, the doctor, work, home. The youngest was 14, the oldest 78. At 12:51 p.m. on Feb. 22, 2011, most of them had seconds to live.
The bus passed a cluster of old, brick buildings downtown, a place with the grit and throwback charm of Seattle’s Pioneer Square. Below the soil was a crack in the bedrock, similar to the one under Seattle, where pressure that had built for centuries finally burst the city’s foundation.
The earthquake shredded buildings and weaponized fragments of brick and concrete, crushing scores of people eating lunch, shopping and talking on the phone. The facade of one old, brick building, home to a noodle shop, separated from its walls and broke over Red Bus No. 702.
Almost six years later, Christchurch’s ruined cityscape warns of the danger a few miles below Seattle, where pressure is building to inevitable violence along a fault extending from the foothills of the Cascades to Hood Canal. The similarities to Christchurch give Seattle officials a rare insight into what the city can expect to face.
New Zealand’s second-largest city and Seattle were settled in the 1850s, constructed of similar materials under similar building codes. Each city also is situated above a fault that is relatively close to the surface, exposing them to a blast of seismic energy far more intense than deeper faults. An earthquake on Seattle’s shallow fault could cause more damage to the city than the so-called Big One, a magnitude 9.0 rupture of the Cascadia Subduction Zone, seismic experts say.
Seattle’s officials have two advantages that their counterparts in Christchurch lacked: They’ve known about the fault for more than 20 years, and they can draw on New Zealand’s experience for ways to blunt the damage and bounce back from it.
New Zealand had learned from its previous earthquakes. The country created a fund in 1945 to cover earthquake damage to insured homes, amassing $5.9 billion by 2010. The Ministry of Education had set higher structural standards for schools by the late 1990s, so when the Christchurch quake struck during school hours, there were no deaths on campuses. And after the tremors turned Christchurch’s historic district into rubble, the Parliament amended the national building law earlier this year to require upgrades to the most at-risk buildings. Read More