A gravimeter or gravitometer,'s an instrument used in gravimetry for measuring the local gravitational field of the Earth. A gravimeter's a type of accelerometer, specialized for measuring the constant downward acceleration of gravity. Though the essential principle of design's the same as in other accelerometers, gravimeters are typically designed to be much more sensitive in order to measure very tiny fractional changes within the Earth's gravity of 1 g, caused by nearby geologic structures o… (More on Gravimeter)