For more information on computation, see the article Bossu et al., 2016:

Regional instrumental seismicity

This seismicity maps have been generated by concatenating the ISC catalogue (since 1964), the EMSC Euro-Med Bulletin catalogue and the EMSC Real Time catalogue. Therefore, they show the seismicity from 1964 until the earthquake occurrence.

Regional deadly earthquakes from 1500 to 2000

Date Long. Lat. Mag. Death Location

1959-08-17 -111.1 44.8 7.1 28 IDAHO-MONTANA BORDER REGION

Source: T. Utsu ; International Handbook of Earthquake and Engineering Seismology; vol. A; 691-718