A seismogragh is a sensative instrument that records seismic waves.
A seismogragh and/or seismometer.
An object that measures the earth to see if there is going to be an earthquake
The distance to the epicentre of an earthquake and it's magnitude.
the exact distance between earth and moon
A seismograph is the reading that comes from a seismometer. They are used to measure the seismic waves that are generated by volcanoes and earthquakes.
The ground shakes moving a needle which is then used to see how strong it was based on how much the needle moved.
A seismograph uses electromagnetic sensors to measure seismic waves in order to detect earthquakes that are too small to feel, as well as detecting and tracking other phenomena.