![]() Seismograms are digital now - there are no more paper recordings. ![]() When there is NO EARTHQUAKE reading, there is just a straight line except for small wiggles caused by local disturbance or "noise" and the time markers. In reality, these mechanisms are no longer manual, but instead work by measuring electronic changes produced by the motion of the ground with respect to the mass.Ī seismogram is the recording of the ground shaking at the specific location of the instrument. On a seismogram, the HORIZONTAL axis = time (measured in seconds) and the VERTICAL axis= ground displacement (usually measured in millimeters). As the seismograph shakes under the mass, the recording device on the mass records the relative motion between itself and the rest of the instrument, thus recording the ground motion. This did not, however, record earthquakes it only indicated that an earthquake was occurring. The first seismograph was developed in 1890.Ī seismograph is securely mounted onto the surface of the earth so that when the earth shakes, the entire unit shakes with it EXCEPT for the mass on the spring, which has inertia and remains in the same place. The earliest "seismoscope" was invented by the Chinese philosopher Chang Heng in A.D. They are installed in the ground throughout the world and operated as part of a seismographic network. ![]() Seismographs are instruments used to record the motion of the ground during an earthquake. Moment magnitude scale was considered for the study because surface-wave magnitude (M s), body-wave magnitude (M b). Measures the total energy released by an earthquake. Based on the analysis of the distribution of the dataset, the reversible conversion relationships between modified Mercalli intensity (MMI) and peak. Developed in 1935 by Charles Richter, this scale uses a seismometer to measure the magnitude of the largest jolt of energy released by an earthquake. A seismometer is the internal part of the seismograph, which may be a pendulum or a mass mounted on a spring however, it is often used synonymously with "seismograph". The predicted ground motion intensity in this study will aid in the safe design of structures and the proper planning of important infrastructure projects. In this study, we use the strong motion records and seismic intensity data from 11 moderate-to-strong earthquakes in the mainland of China since 2008 to develop new conversion equations between seismic intensity and peak ground motion parameters.
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