Tsunami: How high was Japan’s ‘wall of terror?'

Just how terrifying can a tsunami get? Consider two properties of a tsunami: height and speed. The tsunami churned up by the magnitude-8.9 earthquake that hit Japan’s Honshu region was roughly the height of a four-storey building, said Ishmael Narag, the Officer-in-charge of the Philippine Institute of Volcanology and Seismology (Phivolcs) Seismological Observation and Earthquake Prediction Division. Narag explained that a tsunami is not just a wall of seawater. "It’s a wall of seawater carrying a lot of debris, sediments, corals, sand, cars, ships. It’s oftentimes, murky and this can bring about some health complications," he said. A 13-meter high tsunami can travel up to 5 kilometers inland, scarring the earth. Earthquakes magnitude-5 and over can produce tsunamis. A tsunami can race over water at speeds of 500 kilometers per hour (kph) up to 800 kph, while it can travel over land at speeds of 40kph to 50kph. “This is due to the properties of water, it loses very little energy in water," Narag said. How would being caught amid a tsunami feel like? Narag compared it to being awash in a giant washing machine, with water hitting you in all directions together with the debris that the tsunami had swallowed. The Philippines has had its share of tsunamis – at least once every century. Perhaps the deadliest tsunami was the one that hit Pagadian Island in August 17, 1976. A magnitude-7.9 earthquake struck the Moro Gulf generating a 10 meter tsunami, comparable to the height of the waves that hit Japan on March 11 this year. Around 3,500 perished and many more went missing in the Pagadian tsunami. Narag said no coastline is safe from tsunami. Even Manila Bay was hit by a tsunami sometime in 1863. How does one survive a tsunami? “If there’s an earthquake, and you live along a coastline, expect a tsunami and run up to higher ground. That’s what the elders used to tell us," noted Narag. When the sea recedes abruptly in less time than that it normally would during regular low-tide and suddenly some fish are left flopping on the exposed sand, don’t pick up the fish – just run for your life. – MRT, GMA News