Seismogram

• Seismic waves are detected by a seismogram --> produce a seismograph
• The closer a station is to the earthquake, the faster the seismograph will detect waves
• further away the station is = longer to detect waves
• triangulation = 3 seismographs are needed to locate an earthquake --> where three circles meet = earthquake (drawn with compass + s=d/t)

  
• lag time = from start of p waves to start of s
• Pathway of p waves through the Earth: refract at the outer core because it has properties of a liquid. shadow zones = no waves will reach there

  
• pathway of s waves through the earth: stop at boundary of outer core, has properties of a liquid, leaving shadow zone where no s waves can travel