Seismometers

Seismometers are instruments that record any vibrations in the Earth’s surface where they are installed, measuring the speed of oscillation and acceleration achieved by the ground.
Old seismometers were very heavy, with a nib attached and, underneath, a paper roll firmly fixed to the ground. Modern seismometers are totally electronic and can even amplify microseisms that could not be intercepted in the past.
Sismografo