Simplified Seismic Records

Simplified Seismic Records

  • Seismic records capture data about the energy released by earthquakes. This energy travels in the form of waves called seismic waves.

  • Seismic waves can be categorised into two main types: body waves (which travel through the Earth’s interior) and surface waves (which travel along the Earth’s surface).

  • Body waves further divide into two categories. Primary or P-waves are the fastest, moving in a push-pull (compressional) pattern. Secondary or S-waves are slower and move side-to-side or up and down, causing the most damage due to their shaking effect.

  • Surface waves also include two types: Love and Rayleigh waves, both of which cause ground to move in different directions leading to a great deal of destruction.

  • Seismometers are used to detect and record seismic waves. They produce a graphical range of waves called a seismogram. The time interval between the arrival of the P and S-waves at the seismometer helps determine the location of the earthquake’s epicentre.

  • Simplified seismic records help in understanding several aspects of earthquakes. These records provide information about the earthquake’s location, energy magnitude, and the Earth’s internal structure.

  • The study and interpretation of seismic waves fall under the domain of seismology. This knowledge helps in the prediction and preparation for future earthquakes.

  • Make sure to remember that not all waves move through all mediums. For example, P-waves can move through solids, liquids, and gases, but S-waves can only move through solids. This helps seismologists understand the Earth’s inner structure.

  • Note: when revising, take note of the differences between P-waves, S-waves, Love waves, and Rayleigh waves; their speed, direction of motion, and their effects. It’s also worthwhile to understand how seismic records are obtained and interpreted.