Richter magnitude scale Richter correlation tables based on Richter standard seismic event (formula_26, formula_27, formula_28). Below, formula_29 is the epicentral distance (in kilometers unless otherwise specified). The Lillie empirical formula: Where formula_31 is the amplitude (maximum ground displacement) of the P-wave, in micrometers, measured at 0.8 Hz. For distances formula_32 less than 200 km, and for distances between 200 km and 600 km, where formula_31 is seismograph signal amplitude in mm and formula_32 is in km. The Bisztricsany (1958) empirical formula for epicentral distances between 4˚ to 160˚: Where formula_38 is the duration of the surface wave in seconds, and formula_39 is in
Rating scale at the ordinal level. Numbers indicate the relative position of items, but not the magnitude of difference. Attitude and opinion scales are usually ordinal; one example is a Likert response scale: Some data are measured at the interval level. Numbers indicate the magnitude of difference between items, but there is no absolute zero point. A good example is a Fahrenheit/Celsius temperature scale where the differences between numbers matter, but placement of zero does not. Some data are measured at the ratio level. Numbers indicate magnitude of difference and there is a fixed zero point. Ratios can be calculated. Examples include