Andrija Mohorovičić

Andrija Mohorovičić (23 January 1857 – 18 December 1936) was a Croatian geophysicist and academic. He is best known for the eponymous Mohorovičić discontinuity and is considered one of the founders of modern seismology. He is also considered among the greatest Croatian natural scientists.

Early years

Mohorovičić was born in Volosko, Opatija, where his father (also named Andrija) was a blacksmith, specializing in making anchors. The younger Andrija also loved the sea and married a captain's daughter, Silvija Vernić, with whom he had four sons. Mohorovičić obtained his elementary education in his home town, then continued at the gymnasium of neighbouring Rijeka. He received his higher education in mathematics and physics at the Faculty of Philosophy in Prague in 1875, where one of his professors was Ernst Mach. At 15, Mohorovičić knew Italian, English and French. Later he learned German, Latin, and Ancient Greek. In his last paper on meteorology (1901), he discussed the decrease in atmospheric temperature with height. His observations of clouds formed the basis of his doctoral thesis On the Observation of Clouds, the Daily and Annual Cloud Period in Bakar presented to the University of Zagreb and which earned him his degree as doctor of philosophy in 1893. Geophysicists subsequently determined that the crust is 5–9 km below the ocean floor and 25–60 km below the continents, which rest on tectonic plates. Subsequent study of the Earth's interior confirmed the existence of the discontinuity under all continents and oceans.

Mohorovičić assumed that the velocity of seismic waves increases with the depth. The function he proposed to calculate the velocity of seismic waves is called the Mohorovičić law. He developed a method for determining earthquake epicenters and constructed curves giving the travel-times of seismic waves over distances of up to 10,000 miles from their source. He also proposed the construction of a new type of seismograph for recording ground horizontal movement, but due to lack of funds the project was never realized.

As early as 1909 Mohorovičić started giving lectures recommending standards that both architects and building contractors should follow - he was ahead of his time in setting some of the basic principles of earthquake-resistant design. Mohorovičić's theories were visionary and were only truly understood many years later from detailed observations of the effects of earthquakes on buildings, deep focus earthquakes, locating earthquake epicenters, Earth models, seismographs, harnessing the energy of the wind, hail-defence and other related elements of the geological body of knowledge known as geoscience.

Legacy His theories and proposals were the foundation of the "Zagreb school of seismology", which continued his work. Swedish seismologist M. Båth counted Mohorovičić along with 13 other names among the most important researchers in the field of seismology in the 1900-1936 period. That same year, the Croatian Monetary Institute and the National Bank of Croatia issued a gold coin on the occasion of the 150th anniversary of his birth.