Many people acted heroically in the aftermath of Hurricane Katrina. The Coast Guard, for instance, rescued some 34,000 people in New Orleans alone, and many ordinary citizens commandeered boats, offered food and shelter, and did whatever else they could to help their neighbors.
Tidal waves, or tides, are a predictable, com-mon occurrence along coastal communities, generated by forces beyond Earthâthe gravitational pull of the sun and moon. However, tsunamis are not predictable. They are often generated by earth-quakes, volcanic activity, and slope failure.idal waves, or tides, are a predictable, com-mon occurrence along coastal communities, generated by forces beyond Earthâthe gravitational pull of the sun and moon. However, tsunamis are not predictable. They are often generated by earth-quakes, volcanic activity, and slope failure.
* A tsunami is a series of waves with a long wavelength and period (time between crests) generated by a large, impulsive displacement of sea water. * Time between crests of the wave can vary from a few minutes to over an hour, but generally are in the range of 15 to 30 minutes. The most common cause of a tsunami is sea floor uplift associated with an earthquake. * Tsunamis are also triggered by landslides into or under the water surface, and can be generated by volcanic activity and meteorite impacts.