Because people have been far down and we have special tools to see down into the earth.
mantle
There are almost no extrusive rocks on the earths surface because they are all under the earths surface. They are mainly lower than the earths surface.
the moving of the plates under the earths surface
pressure from the heat under the earths surface
There is no ladder if (of?) rocks under the earths surface, your question is meaningless.
the tectonic plates are shifting under the earths surface.
An intrusion.
the tectonic plates under the earths surface
Lava
An earthquake is started when two plates (which lie under the Earths surface) rub together this creates movement which then sometimes pulls/pushes at the earths surface and creates giant cracks in the earths surface... and that is how an earthquake is started.
i dont know what the answer is at all
earthquakes