The very ground itself rises and falls all the time, especially along the coastline.
Some continents, the ocean rises on one coast while it is falling on the other.
The oceans are fairly constant, and do not change their median level. What happens is that the ground (the crust) moves, and makes it appear that the sea is rising or falling.
Just look at the volcanoes that pop up out of the ocean. If you measured sea level around their perimeter, you could conclude the ocean was falling.
Thanks for your input, FRiend!
It takes a FReeper to explain it all.....thanks for the information