Understanding plate tectonics and tectonic forces
We all know that inside of earth is composed of hot magma (molten lava) and above that sits a transitional molten phase of very hot material and on the top of it earth crust is resting. So earth crust is like a solid floating on the hot molten magma below. Unfortunately, the earth crust is not one single piece but is divided in many plates between which there are big cracks or fault zones are present. These plates move on the molten lava below and collide with each other and press each other in different directions. In Geology these are defined as the tectonic plates and the force with which they are pressing each other is known as tectonic force. This tectonic movement is very slow and we sitting on earth do not feel it. When this movement becomes noticeable then we feel earthquakes happening in our place. Sometimes volcanoes also erupt from the junctions of these plates whenever a conducive environment is there for the lava to come out and the volcano spits hot magma on the earth surface. There are so many volcanoes on the earth some of which are still active and we do not know when others will also become active or remain dormant for quite some time.Due to slow collision of these plates mountains are formed in due course of time and because of movement of land masses the oceans also change their place as due to gravity water will always try to remain in low areas.
It is a complex system but is a natural phenomenon and we have to live with it. The emergence of mountains and shifting of oceans is a geological process taking millions of years and we do not perceive them in our lifetime.
Members having interest in Geology may like to add to this information.