An electronic chip containing a proof-mass which can measure ground acceleration or gravitational force. Can be used in a seismic receiver.
Exactly like the accelerometer chip in your laptop or cellphone, these tiny mechanical systems can be housed in a robust casing and used to record seismic waves. Response frequencies range from 4–1000 Hz (8 octaves; theoretically they will measure down to 0 Hz, or DC in geophysish, but not in my experience). Because the instrument operates at frequencies well below the resonant frequency (owing to the very small proof mass armature), it measures particle acceleration.
These are sometimes referred to as digital receivers. Although they are really micro-analog devices, the feedback circuit which measures the displacement is purely digital. The output is therefore digital.
- Geophysical stamps 3: Geophone — blog post and comments