steady as she goes! meaning, steady as she goes! definition | English Cobuild dictionary. steady. 1 adj A steady situation continues or develops gradually without any interruptions and is not likely to change quickly. Despite the steady progress of building work, the campaign against it is still going strong...
Seismic waves are divided into two types: Body waves and surface waves. Body waves include P and S waves, and these are the two types of waves that are used to determine the internal structure of the Earth. (There are other types of seismic waves, but they relate to surface damage and only travel through the Earth s crust, not the entire Earth. If you are interested though, there is a short activity to show you what they are and how they move.
There are three basic types of seismic waves â P-waves4, S-waves5 and surface waves. P-waves and S-waves are sometimes collectively called body waves. P-waves, also known as primary waves or pressure waves, travel at the greatest velocity6 through the Earth. When they travel through air, they take the form of sound waves â they travel at the speed of sound (330 ms-1) through air but may travel at 5000 ms-1 in granite7. Because of their speed, they are the first waves to be recorded by a seismograph8 during an earthquake.