In Our View: Preparing for the Jolt
Local scientists say probability is 'high' for major earthquake in next 25 years
Friday, February 1, 2013
Clark County residents are understandably troubled anytime "Whole Lotta Shakin' Goin' On" transcends the rockabilly artistry of Jerry Lee Lewis.
That's exactly what happened at 5:03 p.m. Wednesday two miles northeast of Amboy when an earthquake of 3.7 magnitude interrupted the serenity of north county. Shaking was felt throughout the region, but, thankfully, no injuries or emergency calls resulted.
We would all do well to heed this wake-up call. And if the rumbling doesn't get your attention, perhaps some expert opinions from scientists will make an impression. The potential of a large, dangerous earthquake is considered "the hazard of greatest risk to Clark County," more threatening than a flood, wildfire or volcanic eruption. That ominous wording appears in the Clark County Hazard Identification Vulnerability Analysis produced by the Clark Regional Emergency Services Agency (CRESA). And according to a Dec. 23, 2012, Columbian story by Sue Vorenberg, the CRESA analysis rates the 25-year probability, vulnerability and risk rating for a strong earthquake as "high."
Prudent response to this danger is costly. The more scientists learn about earthquakes, the more building codes evolve, and that drives up construction costs. But the cost must be incurred, because it also drives up survivability rates of people and buildings.
Local elected officials of all political persuasions should rank survivability above cost, and be ready to adjust municipal construction codes to enhance the community's preparedness.
Most threatened are low-lying areas near bodies of water. As Vorenberg reported, properties near the Columbia River, Vancouver Lake and large creeks are particularly susceptible to liquefaction, the earthquake-induced transformation of mixed soils and sand grains into a substance that temporarily acts like quicksand. When large earthquakes strike these areas, not only are buildings damaged or destroyed, underground infrastructure such as sewer and natural gas line are ruptured and often rise to the top of the liquefaction because of buoyancy.
In assessing the seriousness of this threat, history is instructive. In the past two decades, there have been eight earthquakes at or above 5.0 magnitude in Washington and Oregon. These include the 6.8 Nisqually earthquake near Olympia in 2001 (one fatality, about 700 injuries and damage estimates as high as $4 billion) and the 5.6 earthquake in 1993 centered south of Portland ($28 million in damages). Distant history is even more troubling. Researchers believe five earthquakes of magnitude 8 or above likely occurred around the world between 600 B.C. and 1310 A.D.
The encouraging local news is that many newer buildings in Clark County are relatively safe, compared with older buildings. These stronger structures include Holy Redeemer Catholic Church, 17010 N.E. Ninth St; newer construction at the Washington School for the Deaf, 611 Grand Blvd; Vancouver City Hall, 415 W. Sixth St.; both local hospitals and many newer school buildings.
The discouraging news is that informed minds believe it's only a matter of time before a devastating earthquake hits the West Coast. The Pacific Northwest is threatened by a 700-mile fault about 50 miles out to sea, where the Juan de Fuca geologic plate grinds under the North America plate at a rate of about 1.5 inches a year.
Even if a seismic tragedy doesn't strike soon, ignoring the threat would be correctly viewed by our descendants as an act of deadly negligence.