# scale judges

##### Article

July 5, 2022 The Richter Scale or SR is defined as the logarithm (base 10) of the maximum amplitude, measured in micrometers, from an earthquake recorded by a Wood-Anderson seismometer, at a distance of 100 km from the epicenter. For example, for example, if we have an earthquake record (seismogram) from a seismometer installed 100 km from the epicenter, the maximum amplitude is 1 mm, then the strength of the earthquake is log (10 to the power of 3 micrometers) equal to 3.0 on the Richter scale. This scale was proposed by the physicist Charles Richter. The basic equation used is: M L log 10 ️ A ️ log 10 ️ A 0 ( ️ ) log 10 ️ [ A / A 0 ( ️ ) ] , {\displaystyle M_{\mathrm {L} }\log _{10}A-\log _{10}A_{\mathrm {0} }(\delta )\log _{10}[A/A_{ \mathrm {0} }(\delta )],\ } Where A is the maximum excursion of the Wood-Anderson seismograph. To make it easier for people to determine the Richter scale, without performing complex mathematical calculations, a simple table was made as shown in the following figure. The parameters that must be known are the maximum amplitude recorded by the seismometer (in millimeters) and the difference in travel time between P-waves and S-waves (in seconds) or the distance between the seismometer and the epicenter (in kilometers). In the picture below, an example of a seismogram has a maximum amplitude of 23 millimeters and the difference between the P wave and S wave is 24 seconds, so by drawing a line from the 24 sec point on the left to the 23 mm point on the right, the line will cut the scale 5 ,0. So the scale of the earthquake was 5.0 on the Richter scale. The Richter scale was originally only made for earthquakes that occurred in the Southern California area. However, in its development, this scale was widely adopted for earthquakes that occurred in other places. The Richter scale is only suitable for earthquakes with a magnitude below 6.0. Above that magnitude, calculations using the Richter technique are no longer representative. It should be remembered that the calculation of earthquake magnitude does not only use the Richter technique like this. Sometimes there are misunderstandings in the media reporting about the magnitude of this earthquake because the method used is sometimes not mentioned in the media coverage, so it could be that one agency with another agency issued a magnitude that is not the same.