Hi John. I believe it is an intensity scale such as the Mercalli Scale. Take Care…Don in creepy town

Dec. 7, 1988 - SOVIET UNION - More than 25,000 killed, 18,000 injured. 6.9 Richter, 10 on Soviet 12-point scale. NW Armenia. The town of Spitak almost totally destroyed and Leninakan half destroyed.

In 1964 the first version of the MSK Scale was published by Medvedev, Sponheuer and Karnik (Sponheuer and Karnik, 1964). This new scale was based on MCS, MM56 and previous work by Medvedev in Russia, and greatly developed the quantitative aspect to make the scale more powerful. This scale became widely used in Europe, and received minor modifications in the mid 1970s and in 1981 (Ad hoc group, 1981). In 1988 the European Seismological Commission agreed to initiate a thorough revision of the MSK Scale. The result of this work (undertaken by a large international Working Group under the chairmanship of Gottfried Grünthal, Potsdam) was published in draft form in 1993, with the final version released (after a period of testing and revision) in 1998 (Grünthal, 1998). Although this new scale is more or less compatible with the old MSK Scale, the organization of it is so different that it was renamed the European Macroseismic Scale (EMS). Since its publication it has been widely adopted inside and also outside Europe.

• Intenstiy Scale