CASE STUDIES
THERE HAVE BEEN SEVERAL EXTREME CASES WHERE TSUNAMIS ARE TOTALLY DEVASTATING TO THE
SEASHORE COMMUNITY. IT CAUSED MANY LOSSES, SOME OF WHICH MAY TAKE YEARS TO REPAIR, OR NOT
BE REPAIRABLE AT ALL.
The latest and one of the most powerful tsunami (tidal wave) attack occurred off the north coast of Papau New Guinea. A 10 metre high tsunami engulfed coastal villages a half-hour after undersea quakes of 7 on the Richter Scale struck the region. The filmsy houses, built mainly on the beach, was totally at the mercy tsunami's impact. Seven villages were completely wiped out, and close to a thousand people dead. The death toll is higher though, as many more are reported missing, believed to be swept away by the massive currents. Almost the entire 2nd generation of the villages were gone, drowned in the great mass of water. There was great damage to property as roads, bridges, buildings and villages were destroyed. People built their homes close to the beaches, never anticipating that a tsunami will one day crash into the island. The last tidal wave in the area was dated way back to December 1930, it shows that no one truly is safe from the ocean's vast, violent torrents. PRINCE WILLIAM SOUND, 1964
On March 28, 1964, an earthquake occurred in Prince William Sound of Alaska triggering a Pacific-wide tsunami. The earthquake had a magnitude of 8.4 on the Richter Scale. The earthquake, local tsunamis due to landslides, and the regional tsunami were responsible for taking the lives of more than 122 people and causing over $106 million in damage. One of the waves reached a height of 31.7 m above low tide. At Whittier the waves destroyed two saw-mills; the Union Oil Company tank farms, wharves and buildings; an Alaskan Railroad depot. They also caused great damage to the small boat harbor. The greatest amount of damage suffered by any location was Alaska. In Alaska the death toll was 106 and there was $84 million in damage. Among Alaskan areas the run-up measurements varied from
24.2 m at Blackstone Bay,
27.4 m at Chenega,
9.1 m at Valdez, and
6.1 m at Kodiak.
Outside Alaska it took 5.4 hrs for the first wave to arrive at Hilo, Hawaii, where the run-up was measured at 3.0 m. Another city outside Alaska that received measurable run-up was Crescent City, CA, where a 4.3 m run-up was recorded 4.1 hrs after the tsunami was triggered. Both the railroad yard and seaport facilities at Seward, Alaska, received heavy damage. Even though the regional tsunami was very destructive the local tsunamis also caused significant damage. The local tsunamis were generated by landslides, which were triggered by the earthquake. At the Valdez Inlet a large landslide was triggered by the earthquake generated a tsunami that had a run-up measured at 67.0 m in the inlet. In areas where local tsunamis were generated by landslides nearby cities were given no warning of the oncoming waves. The inability to properly warn the Alaskan region prompted the creation of the Alaska Tsunami Warning Center. The warning center can quickly warn towns of any threat of local tsunamis.