Earthquake countermeasures

Seismic sensors detect the tremors of an earthquake and safely stop the elevator at the closest floor. There is a P-wave sensor which detects the initial tremors, and an S-wave sensor that detects the main tremors.
There are also other countermeasures recommended to prevent equipment falling from the machine room, ropes coming off their pulleys, and ropes and cables becoming caught on protruding objects inside the hoistway.