Cascadia's Fault - Jerry Thompson [82]
The National Oceanographic and Atmospheric Administration, or NOAA, got interested in Cascadia partly because of the small wave the Petrolia quake shot into the harbor in nearby Crescent City, California. Even though it didn’t cause much damage, it did revive painful memories of what had happened in 1964 and it was evidence that a tsunami could be generated by a tectonic source much, much closer to home. Prior to Petrolia the investigation of tsunami damage from Cascadia’s fault had been carried out by geologists and seismologists.
Oceanographers and their math whiz colleagues who were attempting to create numerical models of tsunami wave behavior had been concentrating on waves crossing the Pacific from distant sources like Alaska, Japan, or Chile. Their goal was to predict what a given wave would do and devise a better warning system to alert the West Coast. Suddenly it seemed possible that large and damaging waves could be generated within twenty-five miles (40 km) of the beach all along the coastline of the Pacific Northwest.
Seeing what happened off Cape Mendocino, “NOAA became very excited,” Dengler recalled, “particularly Eddie Bernard at the Pacific Marine Environmental Laboratory in Seattle. This was an event that really allowed him and his modelers to get their teeth into Cascadia and to actually model that tsunami.” Shortly after Petrolia, Eddie Bernard and his wave research team from PMEL were working with state geologists in California to put together a profile of what a larger Cascadia tsunami would look like. Combining a seismic shock and a killer wave in the same scenario had never been done before.
The Petrolia story rang bells in the state capital as well, according to Dengler. “It brought the emergency management community into the picture. Prior to our event, I would say most emergency managers in the state of California weren’t really convinced that Cascadia was a problem. They had a really rapid conversion,” she declared. “And so we saw an incredible surge in momentum with NOAA and the emergency management community, which really culminated in the planning scenario for an 8.4 earthquake on the Cascadia Subduction Zone.”
Dengler paused, looked up, anticipated my next question, then answered it all in the same breath. “Some people say, ‘Well, why an 8.4? Why does it stop at the California border?’Well, this was funded by the state of California. And so, it’s a great document, but it certainly has its limitations.” I took this to mean that the mandate for emergency planning by the governor’s Office of Emergency Services ends at the California state line. The larger scenario for a magnitude 9 catastrophe along the entire Cascadia margin would have to wait until other state, federal, and provincial governments were sufficiently motivated to get involved. For these other jurisdictions to the north, apparently the tipping point had not been reached yet. The good news was that awareness of Cascadia, along with a new sense of urgency, had now spilled across the boundaries from geology to the liquid sciences as well.
Before Sumatra, very few people had seen a tsunami in action. Until those chilling home videos from Thailand and other fatally ruined vacation resorts were broadcast round the world, hardly anybody in the general public knew what a tsunami could do. Even the experts, oceanographers like Eddie Bernard at PMEL and top-ranked wave modelers like Vasily Titov, had only a theoretical appreciation of the beast they were dealing with. They understood the hydrodynamics, they could do the math and had seen photographs of damage done by waves in the distant past, but until Sumatra neither had seen the real thing in real time.
Before Sumatra, the most recent and memorable tsunami had been the one triggered by the 1964 Alaska earthquake. “I was born