Which scientific instrument is most commonly used to study earthquakes?
a. seismograph
b. seismogram
c. oscilloscope
d. radar

Seismographs are scientific instruments used to measure earthquakes. The answer is letter A. Its goal is to detect any slight movement caused by the earth’s crust. It is measured in seismic waves (the waves that the earthquakes’ produce). These waves are recorded in a white paper caused by the weight of the pen. It is called as seismogram. The seismograph can also tell how far and how strong the earthquake was. An oscilloscope is a device used to measure waves produces by a sound. A radar is a system used to detect the distance, direction 

Answercompass direction;