the effect of an earthquake can be measured by a seismometer. it detects the shakes caused and it puts these movements on a seismograph. the strength, or magnitude, of an earthquake, is measured using the richter scale. the richter scale was invented by charles francis richter in 1935. the scale is numbered 0-10. on the scale, 2 is scarcely noticeable, and magnitude 5 (or more) creates damage over a wide area. the largest earthquake ever measured was a 9.5. an earthquake of 10 has never been recorded.