Isoseismal map

Isoseisten are isolines, the loci of the same ( integer ) combine intensities of an earthquake.

The intensity of an earthquake is determined according to the Mercalli scale or according to the MSK scale and usually determined by questionnaire surveys. The intensity is based on the subjective perception of audible and tactile effects and subjective classification of impact damage that causes an earthquake at a given location. Since the effects of the vibrations decrease with distance from the epicenter and also depend on numerous other factors such as the oven operation or the nature of the substrate, it is in the intensity around a stationary dependent variable. It is, therefore, not to be confused with the magnitude of an earthquake.

The determined spatial distribution of the intensities is shown in a so-called Isoseistenkarte. Because of the distance dependence, the Isoseisten always represent a closed path around the epicenter around which are interpolated from the specified local intensities. The shape of the line trains depends in particular on the emission characteristics of the released seismic energy and soil characteristics ( transmission of seismic waves), is in addition also influenced by factors such as the Bevölkerungesdichte and the general ground unrest.

Since the scale used to know only integral values ​​, the innermost of the Isoseisten are simultaneously at the maximum intensity I0. The Isoseistenkarte not only allows the conclusion to the location of the epicenter, but delivers about the distance of one another Isoseisten also clues to the depth of the hypocenter and allowed within the accuracy of the subjective information and statements to the wave propagation and related to geological structures.