Focal Depth Estimation from Intensity Distribution



For the scarcity of data, isoseismal maps frequently cannot be drawn based on the intensity distributions of historic earthquakes. Therefore, the traditional focal depth estimations with isoseismals are out of question for such events. The method presented in this paper, instead of isoseismals, uses the discrete intensity distributions of earthquakes. The focal depth is determined from the observed intensities by the Kövesligethy model using a nonlinear least-squares method. The method is tested for 50 earthquakes and though the results are not satisfactory for intermediate Haromszék-Vrancea events and may be questionable to some crustal earthquakes, too, the method has the capability of depth estimation of historic earthquakes when isoseismals cannot be drawn. Even, when isoseismals are compiled, this method means a more objective solution, because of the subjective nature of isoseismals.


focal depth isoseismal intensity Kövesligethy 


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Copyright information

© Akadémiai Kiadó 1997

Authors and Affiliations

  1. 1.Geodetic and Geophysical Research Institute of the Hungarian Academy of SciencesBudapestHungary

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