Do you know who invented the Seismograph? We know that Seismograph is an instrument used to detect, register and measure the magnitude of Earthquakes. It was Chang Heng, a Philosopher of China in 132 AD and was the first primitive version of the modern Seismograph. Chang Heng’s Seismograph however did not record the earthquake but only detected it. The Greek word “Seimos” means a “Shaking” from which these terms have evolved. The first Seismograph which could record was developed in 1890.
Seismometers, Seismographs and Seismograms
Seismometers, Seismographs and Seismograms are terms that we normally talk about. But what are they actually?. If Seismograph is the instrument, Seismometer is the internal part of the same and Seismogram is the recording of the shaking of the ground at a specific location of the instrument. Seismogram is a graph plotted on a paper, where the Horizontal Axis is Time measured in seconds and Vertical Axis is the Ground Displacement measured in millimeters.
A simple Seismograph instrument is very sensitive to the up-down motions of earth and is like a Weight hanging from a spring. Both Spring and Weight are suspended from a frame that moves along with the motion detected. The relative motion between the weight and the frame provides a measurement of the vertical ground motion. There is a rotating Drum attached to the frame and a pen is attached to the Weight which records any motion in the Seismogram. The present-day Seismographs are digital and do not have any paper recordings.