Seismic tomography Seismic tomography Seismic tomography is a technique for imaging the subsurface of the Earth with seismic waves produced by earthquakes or explosions. P-, S-, and surface waves can be used for tomographic models of different resolutions based on seismic wavelength, wave source distance, and the seismograph array coverage. The data received at seismometers are used to solve an inverse problem, wherein the locations of reflection and refraction of the wave paths are determined. This solution can be used to create 3D images of velocity anomalies which may be interpreted as structural, thermal, or compositional variations. Geoscientists use these images to
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