PLEASE EXPLAIN TIDAL WAVES.

Twice each calendar day the ocean tides wash up and down the beaches.  These are the normal waves of the tides; and some are higher, and lower, than others. Once in a great while, huge wild waves come flooding in over the land, heaping disastrous destruction for miles and miles. The high wall of water sweeps away everything in its path, and then sinks back to the sea. These monster waves are called tidal waves, but really they have little to do with our regular daily tides. A more proper name is "tsunami," the Japanese word for "storm wave."

Several different events may cause a mighty tsunami. After all, the oceans are great basins of water--and as you know water tends to heave and slop around a bit. Sometimes earthquakes tremble and volcanoes erupt deep down on the floor below the oceans. This upsets the sea and causes the water to rise and fall like the waves you make when you drop a pebble in a pond. Unlike our pond waves, however, the huge ocean waves come raging in over land. Great storms at sea may also cause tsunamis. Gale winds may sometimes pile up huge mountains of water that rush toward land at speeds of 500 miles per hour. Needless to say, everyone is thankful that tsunamis are only once-in-a-while happenings.