Cascadia's Fault - Jerry Thompson [90]
By the fall of 1994, Eddie Bernard and his team at NOAA’s Pacific Marine Environmental Laboratory in Seattle were quite far along in developing better technology that would eventually reduce tsunami false alarms. Work on the warning system had begun in 1946 after a tsunami generated in the Aleutian Islands devastated Hilo, Hawaii. The original Pacific Tsunami Warning Center was set up in Ewa Beach, Hawaii, and was operational by 1949. Unfortunately there was a 75 percent false alarm rate in the early years.
Upgrades were installed after the 1960 Chilean quake killed dozens in Hawaii and as many as two hundred people in Japan. After the 1964 Alaska event, yet another series of improvements was made and a second warning center was established in Palmer to concentrate on Alaska, British Columbia, and the U.S. west coast states.
The physical detection and measurement of waves in the deep ocean remained the primary technological challenge. While NASA satellites vastly improved the ability to study the atmosphere and the ocean’s surface from space—which in turn allowed hurricane scientists to look down from above through the eyes of storms and begin forecasting what big waves and seawater surges would do as they approached the coast—there was still no real-time alarm system that could tell the scientists at NOAA that a seafloor rupture had triggered a tsunami.
Up to that time the two tsunami warning centers depended on data from a network of seismographs to tell them exactly where an earthquake had occurred and what the magnitude was. If they confirmed that the epicenter was under the ocean floor—and if the magnitude was greater than 7—it was entirely possible (but not guaranteed) that a tsunami had been generated. Whether or not to issue a warning was still an educated guess because sometimes the sea floor moves horizontally more than it does vertically. And without the vertical upheaval, a mountain of water does not get lifted and no significant wave is created.
When a tsunami reaches the nearest shore, tide gauges register the sudden sea-level change. By the time the reading is taken, though, it’s often too late to issue a warning to nearby residents. So those living closest to the zone that triggers the wave are simply out of luck.
There would, of course, still be plenty of time to warn coastal communities on the far side of the ocean. The waves will take hours to cross the sea. But if those tide gauges closest to the zone did not survive the initial impact—if the equipment was destroyed by the force of the incoming wave—there would still be no measurement of how big the tsunami was. Decision makers on duty in the warning centers would not be able to tell people living thousands of miles away what to expect when the waves finally reached them. So the decision to issue a warning, or not, was frequently based on incomplete evidence. NOAA had no hard physical data of its own that confirmed the creation, size, and movement of big waves. The system could not avoid false alarms or the tendency to overstate potential threats.
It was a problem that had to be fixed and Stephanie Fritts wasn’t the only one trying to deal with the downstream consequences. Emergency planners in British Columbia and all five Pacific states had already been through enough false alarms to know that evacuations were not only dangerous and disruptive—they were also expensive.
In full-scale evacuations, businesses were suspended. Factories had to be shut down. Restarting complex equipment and production lines always took time and money. In Hawaii, state