Even though Tuesday's 6.3-magnitude earthquake was weaker than last year's 7.1 event, it was much shallower, was situated directly under Christchurch, hit during the lunch hour when more people were exposed to damage, and shook sediments that were prone to "liquefaction," which can magnify the damage done by the ground shaking, PhysOrg.com reported.
Robert Yeats, a professor of geology at Oregon State University, says that same description matches what could happen in many major cities and towns in Washington, Oregon, California and British Columbia.
"The same characteristics that caused such destruction and so many deaths in Christchurch are similar to those facing Portland, Seattle, parts of the Bay Area and many other West Coast cities and towns," Yeats said. "And it's worth keeping in mind that New Zealand has some of the most progressive building codes in the world. They are better prepared for an earthquake like this than many U.S. cities would be."
Like much of the West Coast, Yeats said, New Zealand sits near a major boundary of the Earth's great plates -- in this case, the junction of the Australia Plate and the Pacific Plate.
Despite intensive seismic studies in that nation, no one had yet identified the related fault that devastated Christchurch.
"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 said. "But when you combine the shallow depth, proximity to a major city and soil characteristics, it was capable of immense damage."
There are dozens if not hundreds of similar faults that can cause serious earthquakes in the U.S. and Canadian West, Yeats said.