 The Seismic Method .3 s .1 s .5 s 0 s .2 s .4 s .6 s .7 s .8 s 0 s Some Energy is Reflected Most Energy is Transmitted Energy Source .1 s .5 s Some Energy is Reflected Most Energy is Transmitted  An Explosion! 0 s .2 s .4 s Listening Devices .6 s .7 s .8 s 0 s SLIDE 3 This slide illustrates the basics of reflection seismology We start with an energy source – like an explosion Acoustic energy radiates down through the Earth (represented by the half-circles and the arcs) For simplicity, geophysicists use rays (lines with arrows) to represent the acoustic energy traveling through the Earth At a boundary between one unit and the next deeper unit, some of energy is reflected – most is transmitted (continues to travel down) The reflected energy travels towards the surface where we have set out “listening” devices In this cartoon example, some energy is reflected off the top of the orange unit and is “heard” (recorded) at 0.4 seconds at the receiver near the middle of the diagram Most of the energy is transmitted through the orange layer At the top of the brown layer, some energy is reflected and is recorded at 0.8 seconds at the receiver on the right side of the diagram Courtesy of ExxonMobil L 5 – Seismic Method