MONITOR AND WARNING APPARATUS AND METHODS

摘要

Apparatus including a mass suspended from a filament, and a sensor adapted to sense a change in a time derivative of a spatial position of the mass when the mass moves from a first material to a second material. The change in the time derivative may include acceleration, deceleration, jerk or impact of the mass, for example. The change in the time derivative may be due to the mass being removed from a liquid to a gas, lowered from a gas to a liquid or abutting against a solid surface, such as the bottom of a well, for example. The change in the time derivative of a spatial position of the mass may also be due to seismicity.