Tsunami warning signals began blaring across all islands just after 6 a.m. today and tourists in Waikiki were told to head to higher floors inside their hotels.By comparison, the 2004 tsunami that hit the Indian Ocean had waves estimated at 24 meters.
Officials at the Pacific Tsunami Warning Center say this morning's tsunami wave should arrive at a height of 2.5 meters — or just over 8 feet — when it hits the Big Island at 11:19 a.m.
By the time it reaches Oahu 40 minutes later, the waves should only be a meter or less.
A meter is equivalent to 39 inches. But officials urged people not to be lulled by the relatively small wave heights in a state accustomed to monster waves.
The tsunami, like all others, behaved very differently in deep water than in shallow water. In deep ocean water, tsunami waves form only a small hump, barely noticeable and harmless, which generally travels at a very high speed of 500 to 1,000 km/h (310 to 620 mph); in shallow water near coastlines, a tsunami slows down to only tens of kilometres an hour but in doing so forms large destructive waves. Scientists investigating the damage in Aceh found evidence that the wave reached a height of 24 m when coming ashore along large stretches of the coastline, rising to 30 m (100 ft) in some areas when travelling inland.