GEOLOGY

Detailed explanation-1: -seismograph, instrument that makes a record of seismic waves caused by an earthquake, explosion, or other Earth-shaking phenomenon.

Detailed explanation-2: -Seismographs are instruments used to record the motion of the ground during an earthquake. They are installed in the ground throughout the world and operated as part of a seismographic network.

Detailed explanation-3: -Detailed Solution. The correct answer is Earth Quake. A seismograph records the waves reaching the surface during an earthquake.

Detailed explanation-4: -To overcome this problem, modern seismograph stations have three separate instruments to record horizontal waves-(1) one to record the north-south waves, (2) another to record east-west waves, and (3) a vertical one in which a weight resting on a spring tends to stand still and record vertical ground motions.

Detailed explanation-5: -A seismograph is a machine which measures an earthquake.