First of all, let me start out by saying that my heart goes out to all of the victims of this most horrific natural disaster.

With that said, let me say that a strike-slip fault like this one, which does not release the tension that has built up in it over a long period of time, produces the most dangerous and destructive types of Earthquakes as is evident in Haiti. It's true that there are parts of the San Andreas fault where the tension is allowed to build up over a long period of time, resulting in very destructive Earthquakes. But there are sections of the San Andreas fault where the tension is released on a more frequent and regular basis, resulting in only minor tremors barely noticed, if at all, by local residents. And then there are fault systems like the New Madrid fault. This is one of those fault systems that builds up tension over long periods of time resulting in devastating Earthquakes. An Earthquake from the New Madrid fault could occur at any time between now and 300 years from now. There's no way of predicting an Earthquake. Seismologists can only give rough estimates based on previous behavior and also the geological causes underlying an Earthquake. What almost no one knows about the New Madrid fault is that it is sitting on top of a rift, which will in time tear the US in two. This is the kind of cool stuff you learn when you study geology at a major research institution like my alma mater, UIC. Not so cool, however, for the victims of the Earthquakes that will ensue when the New Madrid fault finally releases the tension that has been building. When the tension is finally released from the New Madrid fault, it's going to be bad.....I mean really, really bad! What will happen is a series of powerful Earthquakes over a period of six months. I'm not talking about aftershocks. I'm talking about a full-blown Earthquake after Earthquake, over and over again for six months! Can you imagine what it will be like for the residents of St. Louis, Missouri?

My old geology professor, Kelvin S. Rodolfo (pictured left) who took an early retirement from UIC so he could study the lahars that persisted for two years after the eruption of Mount Pinatubo and is now  an Adjunct Professor at the National Institute of Geological Sciences, University of the Philippines working as a hazard-mitigation scientist, used to say to us, "Earthquakes don't kill people.....buildings do! And he was so right about that. Ironically, a well-built wooden structure has a much better chance of surving an Earthquake than a brick building, simple because it is more flexible and can absorb the shock and shaking of an Earthquake better. Brick buildings are the first to go in an Earthquake. A steel reinforced concrete structure will hold up better, but unless the structure is specifically reinforced to withstand an Earthquake, they too can fail. The technology of foundations that have flex which can absorb the shock and shaking of Earthquakes is also a good defense against Earthquakes.

P-waves are not only less destructive than S-waves because they're less powerful than S-waves, but also because they have a push/pull motion to them. They are compressional waves. S-waves, on the other hand, are a transverse or shear wave and have either a lateral motion to them or an up and down rolling kind of motion, depending upon the orientation of the wave with respect to the surface. It's this shearing or rolling action that causes the ground to shake violently and tear buildings apart. A phenomenon known as liquefaction also occurs as a result of S-waves, in which the surface literally becomes like a liquid and buildings sink right into the ground. With the focus of the Earthquake in Haiti being only about 10-15 kilometers below the land's surface, the destructive force of the S-wave was beyond imagination as is, unfortunately, evident in Haiti. It is the combination of these factors that led to such a high death toll. So, it really is important to know where you live and be prepared for the natural disasters to which the region in which you live is susceptible.