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How to Measure Seismic Accelerations

Seismic acceleration, frequently referred to as peak ground acceleration, is a measure of the velocity of a seismic event. The value of this measurement is determined by a number of causes, including the proximity of the place of the initial measurement to the epicenter, the strength of the earthquake and the strength and frequency of any subsequent after shocks. Measuring seismic acceleration requires access to a accelerometer, an instrument that measures seismic wave acceleration that is installed in buildings and triggered by P-waves produced by earthquakes.

Things You'll Need

Accelerometer
Calculator

Instructions

- 1
  Read and record the measurement obtained from the accelerometer after a seismic event. Most accelerometer readings are produced by a digital display in a unit of feet per second, but measurements for slower-moving seismic events may be in inches per second. You can also often find data read from an accelerator online or at geological study facilities.
- 2
  Input the reading into your calculator and then square it.
- 3
  Divide the reading in feet per second that has been squared by 32.2. If your reading is in inches per second, divide the squared number by 386.
- 4
  Multiply the figure found above by 100 percent. This will give you the seismic acceleration in the unit of Gs, or gravitational acceleration.

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