Seismic wave Seismic wave Seismic waves are waves of energy that travel through the Earth's layers, and are a result of earthquakes, volcanic eruptions, magma movement, large landslides and large man-made explosions that give out low-frequency acoustic energy. Many other natural and anthropogenic sources create low-amplitude waves commonly referred to as ambient vibrations. Seismic waves are studied by geophysicists called seismologists. Seismic wave fields are recorded by a seismometer, hydrophone (in water), or accelerometer. The propagation velocity of the waves depends on density and elasticity of the medium.Velocity tends to increase with depth and ranges from approximately 2 to 8 km/s in
Venus effect viewers see is different from what the actor sees, because the camera is not right behind the actor, but the position of the actor is often chosen so that his or her image is nicely framed in the mirror for the camera. Although the name of the effect refers to a woman, Venus, the effect is more general. The effect is seen with an animal apparently looking at itself in a mirror in "The Lady and the Unicorn" (French: "La Dame à la licorne") tapestries, where the unicorn appears to be gazing at its own reflection as it kneels on