1. Techniques
   1. Seismographs
      1. What?
         1. seismic waves
         2. detects
         3. measures
         4. records
      2. types
         1. horizontal
         2. vertical
2. Magnitude
   1. Richter scale
      1. log scale
      2. energy
         1. 30 fold increase
3. Waves
   1. Primary (p)
      1. fast
      2. molten interior
      3. material
         1. compress
         2. expand
         3. causes
            1. vibrations
            2. back
            3. forth
   2. Secondary (s)
      1. medium speed
      2. solid rock
      3. vibrates
         1. right angles
   3. Surface
      1. Slowest
      2. material
         1. up
         2. down
4. Locating epicentre
   1. Topic