We won’t know what a Pacific Northwest subduction zone earthquake and tsunami are like until we’ve experienced them. But considering the consequences, we’re fools if we don’t take reasonable long-term steps to mitigate the damage.
U.S. Maria Cantwell’s recent workshop meeting in Long Beach overflowed with disturbing information, including the latest scientific modeling estimates from Dr. Christopher Sabine, director of NOAA Pacific Marine Environmental Laboratories in Seattle. His statements and maps were drawn specifically for the Long Beach Peninsula, but the scenario he outlined is generally applicable to low-elevation communities up and down the coast.
Drawing in part upon data gleaned from the 2011 disaster in Japan, Sabine’s lab suggests the land surface could drop as much as two to four meters or 6.5 to 13 feet as the subduction zone releases centuries of pent-up motion and ocean waters rush in. Until now, discussion has centered on a top-end figure about half as much.
The first in a resulting series of several tsunamis — in effect giant ripples in the ocean — could approach a height of 60 feet right along the seashore. The aftereffects of so much water will transform the landscape.
Damage elsewhere in the region means survivors on the coast face a long wait for help.
Cantwell examined the site of a proposed vertical evacuation structure in Long Beach — basically a tower with a refuge on top. The new research suggests the current design isn’t tall enough. The potential for a lengthy time before rescue urges a strong need to incorporate basic water, food and first-aid supplies.
Discussions suggested a need for dozens of these structures along the low-lying coast. Obtaining funds is almost unimaginable and such an enterprise could turn into a major boondoggle.
The latest subduction theories also reinforce the idea that Columbia estuary communities are at grave risk for major inundation.
We all hope for something far less than the worst prospects laid out by scientists. However, moving forward, there are many conservative and pragmatic steps that can be taken on a generational timescale to begin lessening the potential death toll.
As schools, hospitals, fire stations and other vital facilities approach obsolescence, they must be relocated to higher elevations and built to survive violent shaking.
East-west streets and recreational trail systems should be engineered and laid out in hopes they will serve as pedestrian escape routes to higher ground.
Zoning and subdivision decisions should gradually seek to shift growth into safer elevations, while building codes incorporate up-to-date understanding of the seismic risks we face.
By gradually helping to fund these and other steps now, the federal government may avoid far greater expenses in the future, and save a lot of lives.