During his research on seismology, Croatian scientist Andrija Mohorovičić examined data from an earthquake occurring in Zagreb. His analysis led him to identify an unusual deflection in the graphs, but this one was at a shallower depth than previously noted. This crucial observation marked the discovery of a significant geological boundary.

Mohorovičić's finding delineated the crust from the underlying mantle, a discovery that became known as the Mohorovičić discontinuity, or simply the Moho. This term has been widely adopted in the field of geology and continues to be essential in understanding Earth's structure.