The article presents the results of FCAZ-recognition of the strongest (M ≥ 7.75) earthquake-prone areas on the Pacific coast of the Kamchatka Peninsula and strong (M ≥ 6.5) earthquake-prone areas in California. For the first time, earthquake epicenters from declustered catalogs were used as recognition objects. Based on the example of the considered regions it is shown that the presence of foreshock and aftershock sequences in the earthquake catalogs does not significantly affect the results of FCAZ-recognition based on the clustering study of weak earthquake epicenters.