Earthquakes continue to be in the news as a strong magnitude 6.0 struck eastern Turkey on Monday and southern Taiwan late last week.  However in contrast to the the more severe quakes that struck Haiti and Chile over the past couple of months, there was not a threat for a tsunami.  No less the impact that tsunamis can have was brought back to the forefront in December 2006 following a significant earthquake off the west coast of Sumatra, Indonesia that rippled through the Indian Ocean and devastated parts of Indonesia, Ski Lanka and Thailand killing nearly 230,000 people.  First and foremost, earthquakes are a common occurrence around the world, particularly along the active fault lines stretching from the Indian Ocean over into the Pacific, as well as the more notable faults found in the western and southcentral parts of the US.  Most of the tremblers produced however are usually light to moderate in intensity and obviously don't get a lot of attention.  But when magnitudes of 6 or higher result, there is a better likelihood that at least some structural damage can occur.

But let's get back to tsunamis.  They are defined as a series of waves generated by an impulsive disturbance in the ocean or a body of water, which can inflict severe damage to property and can be a threat to life in coastal communities.  Tsunamis can be caused not only by earthquakes, but also volcanic eruptions, detonation of underwater explosives, and yes even landslides underwater.  Tsunamis may only be a few inches high out in open ocean, but they can travel at speeds close to 500 mph.  Don't believe it? Check out this interactive map on travel times of a tsunami from the epicenter of an earthquake.  As this wave of energy approaches the coastline, typically the water levels will fall and increase with dramatic contrasts.  At first the ocean water may become discolored in appearance as sediment from the ocean floor is pulled up to the surface.   In addition, the tide may fall anywhere from a few inches to several feet as water gathers offshore.  If you remember from the tsunami off the Asia coast and even that one that one that delivered a glancing blow to Hawaii late last month, ocean reefs and the sea floor can be exposed for several minutes, before the surge of water rushes back in.  Of course, the height of the surge of water can be dramatic, ranging anywhere from say a few feet to 50-100 feet, which then rushes quickly inland, up to a few miles away from the coast depending on the topography of the area being impacted.  Although there was little impact from the tsunami caused by the Chile earthquake in Australia, Hawaii, Japan or other western Pacific Countries, there was a localized 50 foot tsunami that rolled into coastal Chile not too long after the earthquake struck.  Reports were that nearly 80 people died in the aftermath of this surge of water.

One thing that tsunamis are not is a tidal wave.  Just think of those large waves that surfers would love to ride...which are single waves of water that are caused by strong storms or which the moon phase may have on tides.  In other words, a tsunami is not a single wave of water that blasts in, but instead is a series of waves of water surging onshore.  Fortunately for us here in Wisconsin, a tsunami is not likely to hit the eastern shore of the state along Lake Michigan following a tremor.  No less, if you are ever taking a trip out to coastal spots in the US or any other parts of the world, it is always good to be knowledgeable of what to do if a natural disaster strikes.  From earthquakes, to volcano eruptions, to tsunamis,  landslides, flooding, wild fires, you name it.  It's always best to be prepared for the worst and hope for the best!