Intensity Estimation Using the MSK-64 and EMS-98 Scales for Selected Historical Earthquakes

Two different approaches for the comparison of the intensity estimation using the MSK-64 and EMS-98 scales are presented for historical earthquakes: 1) a direct comparison of the scales; 2) intensity estimation for selected historical earthquakes using the both scales. The scales are directly compared in the graphic forms. First, the graphic form of the EMS-98 was constructed. The effects on humans, and objects and nature were displayed in the form of tables. The tables include the size of the effects for all intensities. The definition of damage to buildings was displayed in the form of vulnerability class vs. damage grade table for each intensity degree separately. The MSK-64 scale was re-arranged into the same form as the EMS-98 scale. Then the classification of buildings, definitions of quantities and damage grades were compared. Finally, the effects on people, effects on objects and nature, and damage to buildings were compared separately. The effects, which are used only in one of the scales, and the effects, which are used in the both scales were identified. The cases where the differences in the intensity estimation can reach up to one degree are shown and discussed. The situations where the intensity estimation can be done using only one of the scales are also shown and discussed. The graphic forms of the MSK-64 and EMS-98 scales enable us to identify how the observed effects correspond to the defined effects for an intensity degree. Intensity estimations using the both scales were compared for the January 15, 1858 Zilina (Slovakia) and January 25, 1348 Friuli earthquakes. Examples of different intensity estimations using the both scales are given.