The change in direction of a beam of light as it travels from one material to another is called refraction. The normal is a construction line drawn at right angles to the surface of the glass block.

The various methods include gravity, magnetic, electric, electromagnetic, and seismic refraction and reflection. These methods can be applied to multiple areas such as environmental contamination ...

During the summer of 1984 a refraction seismic survey was conducted at Martinique ... Current theories based upon nearshore marine seismic reflection profiles and coastal barrier coring indicate that ...