Andrija Mohorovicic
Encyclopedia
Andrija Mohorovičić (̝ǎndri̞ja mɔ̝xɔ̝rɔ̝̌vi̞ʧi̞ʨ) (January 23, 1857 – December 18, 1936) was a Croatia
n meteorologist and seismologist. He is best known for the eponymous
Mohorovičić discontinuity
and is considered a founder of modern seismology
.
, Opatija
, where his father (also named Andrija), was a blacksmith, making anchors. The younger Andrija also loved the sea and married a captain's daughter, Silvija Vernić. They 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.
gymnasium (1879–1880), then at secondary school in Osijek
. From 1882, he taught for nine years at the Royal Nautical School in Bakar
, near Rijeka. Work started or completed there was important to his later scientific career. From 1893, when he became a corresponding member of the Faculty of Philosophy, University of Zagreb
, to 1917-18 he taught in the fields of geophysics
and astronomy
. In 1898 he became a full member of what was then the Yugoslav Academy of Sciences and Arts in Zagreb, where he was a private docent. In 1910 he became titular associate university professor.
he was first exposed to meteorology
, which he taught at the Royal Nautical School. This influenced him to the extent that he founded the local meteorological station in 1887. He made systematic studies and both invented and constructed instruments to observe precipitation in Croatia
and Slavonia
. At his own request in 1891, he was transferred to the secondary school in Zagreb
where, in 1892, he founded the Meteorological Observatory in Grič and established a service for all Croatia, while teaching geophysics
and astronomy
at the university
.
On 13 March 1892, he observed the tornado
in Novska
, which picked up a 13 ton railway carriage with fifty passengers and threw it 30m. He observed also the "vihor" (whirlwind) near Čazma
in 1898 and studied the climate
in Zagreb. In his last paper on meteorology (1901), he discussed the decrease in atmospheric temperature
with height. His observations of cloud
s 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.
with its epicentre in the Pokuplje region, 39km southeast of Zagreb. A number of existing seismographs were installed before and provided invaluable data upon which he made new discoveries. He concluded that when seismic
waves strike the boundary between different types of material, they are reflected and refracted, just as light is when striking a prism, and that when earthquakes occur, two waves—longitudinal
and transverse
—propagate through the soil with different velocities
.
By analyzing data from more observation posts, Mohorovičić concluded that the Earth
has several layers above a core. He was the first to establish, based on the evidence from seismic waves, the discontinuity that separates the Earth's crust
from its mantle
. This is now called the Mohorovičić discontinuity
or (because of the complexity of that name) Moho. According to Mohorovičić, a layered structure would explain the observation of depths where seismic waves change speed and the difference in chemical composition between rocks from the crust and those from the mantle. From the data, he estimated the thickness of the upper layer (crust) to be 54 km. We know today that the crust is 5–9 km below the ocean
floor and 25–60 km below the continent
s, which are carried on tectonic plates.
Subsequent study of the Earth's interior
confirmed the existence of the discontinuity under all continents and oceans. 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.
Mohorovičić retired in 1921. Crater Mohorovičić
(on the Moon
's far side) is named in his honour. A Gymnasium
in Rijeka
, Croatia and a school ship in the Croatian Navy are named after him, as was (in 1996) asteroid
8422 Mohorovičić
.
Croatia
Croatia , officially the Republic of Croatia , is a unitary democratic parliamentary republic in Europe at the crossroads of the Mitteleuropa, the Balkans, and the Mediterranean. Its capital and largest city is Zagreb. The country is divided into 20 counties and the city of Zagreb. Croatia covers ...
n meteorologist and seismologist. He is best known for the eponymous
Eponym
An eponym is the name of a person or thing, whether real or fictitious, after which a particular place, tribe, era, discovery, or other item is named or thought to be named...
Mohorovičić discontinuity
Mohorovičić discontinuity
The Mohorovičić discontinuity , usually referred to as the Moho, is the boundary between the Earth's crust and the mantle. Named after the pioneering Croatian seismologist Andrija Mohorovičić, the Moho separates both the oceanic crust and continental crust from underlying mantle...
and is considered a founder of modern seismology
Seismology
Seismology is the scientific study of earthquakes and the propagation of elastic waves through the Earth or through other planet-like bodies. The field also includes studies of earthquake effects, such as tsunamis as well as diverse seismic sources such as volcanic, tectonic, oceanic,...
.
Early years
Mohorovičić was born in VoloskoVolosko
Volosko is a part of the city of Opatija, located in the Kvarner Gulf in western Croatia. It is located in the north of Opatija, on the road towards Kastav and Rijeka.-People:* Amelia Milka Sablich, born there...
, Opatija
Opatija
Opatija is a town in western Croatia, just southwest of Rijeka on the Adriatic coast. , the town proper had a population of 7,850, with the municipality having a total 12,719 inhabitants.-Geography:...
, where his father (also named Andrija), was a blacksmith, making anchors. The younger Andrija also loved the sea and married a captain's daughter, Silvija Vernić. They had four sons.
Mohorovičić obtained his elementary education in his home town, then continued at the gymnasium of neighbouring Rijeka
Rijeka
Rijeka is the principal seaport and the third largest city in Croatia . It is located on Kvarner Bay, an inlet of the Adriatic Sea and has a population of 128,735 inhabitants...
. He received his higher education in mathematics and physics at the Faculty of Philosophy in Prague
Prague
Prague is the capital and largest city of the Czech Republic. Situated in the north-west of the country on the Vltava river, the city is home to about 1.3 million people, while its metropolitan area is estimated to have a population of over 2.3 million...
in 1875, where one of his professors was Ernst Mach
Ernst Mach
Ernst Mach was an Austrian physicist and philosopher, noted for his contributions to physics such as the Mach number and the study of shock waves...
. At 15, Mohorovičić knew Italian, English and French. Later he learned German, Latin and Ancient Greek.
Career in education
He taught first at the ZagrebZagreb
Zagreb is the capital and the largest city of the Republic of Croatia. It is in the northwest of the country, along the Sava river, at the southern slopes of the Medvednica mountain. Zagreb lies at an elevation of approximately above sea level. According to the last official census, Zagreb's city...
gymnasium (1879–1880), then at secondary school in Osijek
Osijek
Osijek is the fourth largest city in Croatia with a population of 83,496 in 2011. It is the largest city and the economic and cultural centre of the eastern Croatian region of Slavonia, as well as the administrative centre of Osijek-Baranja county...
. From 1882, he taught for nine years at the Royal Nautical School in Bakar
Bakar
Bakar ) is a town in the Primorje-Gorski Kotar County in western Croatia. The population of the town is 1,566 , while the population of the municipality is 7,773. 90% declare themselves Croats . The old part of Bakar is situated on a hill overlooking the Bay of Bakar...
, near Rijeka. Work started or completed there was important to his later scientific career. From 1893, when he became a corresponding member of the Faculty of Philosophy, University of Zagreb
University of Zagreb
The University of Zagreb is the biggest Croatian university and the oldest continuously operating university in the area covering Central Europe south of Vienna and all of Southeastern Europe...
, to 1917-18 he taught in the fields of geophysics
Geophysics
Geophysics is the physics of the Earth and its environment in space; also the study of the Earth using quantitative physical methods. The term geophysics sometimes refers only to the geological applications: Earth's shape; its gravitational and magnetic fields; its internal structure and...
and astronomy
Astronomy
Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...
. In 1898 he became a full member of what was then the Yugoslav Academy of Sciences and Arts in Zagreb, where he was a private docent. In 1910 he became titular associate university professor.
Meteorology
In BakarBakar
Bakar ) is a town in the Primorje-Gorski Kotar County in western Croatia. The population of the town is 1,566 , while the population of the municipality is 7,773. 90% declare themselves Croats . The old part of Bakar is situated on a hill overlooking the Bay of Bakar...
he was first exposed to meteorology
Meteorology
Meteorology is the interdisciplinary scientific study of the atmosphere. Studies in the field stretch back millennia, though significant progress in meteorology did not occur until the 18th century. The 19th century saw breakthroughs occur after observing networks developed across several countries...
, which he taught at the Royal Nautical School. This influenced him to the extent that he founded the local meteorological station in 1887. He made systematic studies and both invented and constructed instruments to observe precipitation in Croatia
Croatia
Croatia , officially the Republic of Croatia , is a unitary democratic parliamentary republic in Europe at the crossroads of the Mitteleuropa, the Balkans, and the Mediterranean. Its capital and largest city is Zagreb. The country is divided into 20 counties and the city of Zagreb. Croatia covers ...
and Slavonia
Slavonia
Slavonia is a geographical and historical region in eastern Croatia...
. At his own request in 1891, he was transferred to the secondary school in Zagreb
Zagreb
Zagreb is the capital and the largest city of the Republic of Croatia. It is in the northwest of the country, along the Sava river, at the southern slopes of the Medvednica mountain. Zagreb lies at an elevation of approximately above sea level. According to the last official census, Zagreb's city...
where, in 1892, he founded the Meteorological Observatory in Grič and established a service for all Croatia, while teaching geophysics
Geophysics
Geophysics is the physics of the Earth and its environment in space; also the study of the Earth using quantitative physical methods. The term geophysics sometimes refers only to the geological applications: Earth's shape; its gravitational and magnetic fields; its internal structure and...
and astronomy
Astronomy
Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...
at the university
University
A university is an institution of higher education and research, which grants academic degrees in a variety of subjects. A university is an organisation that provides both undergraduate education and postgraduate education...
.
On 13 March 1892, he observed the tornado
Tornado
A tornado is a violent, dangerous, rotating column of air that is in contact with both the surface of the earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. They are often referred to as a twister or a cyclone, although the word cyclone is used in meteorology in a wider...
in Novska
Novska
Novska is a town in Croatian Slavonia, located between Kutina and Nova Gradiška, southeast of the capital, Zagreb. It has a total population of 13,573 in the following settlements:* Bair, population 6* Borovac, population 276* Brestača, population 911...
, which picked up a 13 ton railway carriage with fifty passengers and threw it 30m. He observed also the "vihor" (whirlwind) near Čazma
Cazma
Čazma is a town and municipality in Bjelovar-Bilogora County, Croatia. It is part of Moslavina.-Geography:Čazma is situated 60 kilometers east of Zagreb and only 30 kilometres from the center of the region - Bjelovar....
in 1898 and studied the climate
Climate
Climate encompasses the statistics of temperature, humidity, atmospheric pressure, wind, rainfall, atmospheric particle count and other meteorological elemental measurements in a given region over long periods...
in Zagreb. In his last paper on meteorology (1901), he discussed the decrease in atmospheric temperature
Temperature
Temperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...
with height. His observations of cloud
Cloud
A cloud is a visible mass of liquid droplets or frozen crystals made of water and/or various chemicals suspended in the atmosphere above the surface of a planetary body. They are also known as aerosols. Clouds in Earth's atmosphere are studied in the cloud physics branch of meteorology...
s 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
University of Zagreb
The University of Zagreb is the biggest Croatian university and the oldest continuously operating university in the area covering Central Europe south of Vienna and all of Southeastern Europe...
and which earned him his degree as doctor of philosophy in 1893.
Seismology
On October 8, 1909 there was an earthquakeEarthquake
An earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. The seismicity, seismism or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time...
with its epicentre in the Pokuplje region, 39km southeast of Zagreb. A number of existing seismographs were installed before and provided invaluable data upon which he made new discoveries. He concluded that when seismic
Seismology
Seismology is the scientific study of earthquakes and the propagation of elastic waves through the Earth or through other planet-like bodies. The field also includes studies of earthquake effects, such as tsunamis as well as diverse seismic sources such as volcanic, tectonic, oceanic,...
waves strike the boundary between different types of material, they are reflected and refracted, just as light is when striking a prism, and that when earthquakes occur, two waves—longitudinal
Longitudinal wave
Longitudinal waves, as known as "l-waves", are waves that have the same direction of vibration as their direction of travel, which means that the movement of the medium is in the same direction as or the opposite direction to the motion of the wave. Mechanical longitudinal waves have been also...
and transverse
Transverse wave
A transverse wave is a moving wave that consists of oscillations occurring perpendicular to the direction of energy transfer...
—propagate through the soil with different velocities
Velocity
In physics, velocity is speed in a given direction. Speed describes only how fast an object is moving, whereas velocity gives both the speed and direction of the object's motion. To have a constant velocity, an object must have a constant speed and motion in a constant direction. Constant ...
.
By analyzing data from more observation posts, Mohorovičić concluded that the Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
has several layers above a core. He was the first to establish, based on the evidence from seismic waves, the discontinuity that separates the Earth's crust
Crust (geology)
In geology, the crust is the outermost solid shell of a rocky planet or natural satellite, which is chemically distinct from the underlying mantle...
from its mantle
Mantle (geology)
The mantle is a part of a terrestrial planet or other rocky body large enough to have differentiation by density. The interior of the Earth, similar to the other terrestrial planets, is chemically divided into layers. The mantle is a highly viscous layer between the crust and the outer core....
. This is now called the Mohorovičić discontinuity
Mohorovičić discontinuity
The Mohorovičić discontinuity , usually referred to as the Moho, is the boundary between the Earth's crust and the mantle. Named after the pioneering Croatian seismologist Andrija Mohorovičić, the Moho separates both the oceanic crust and continental crust from underlying mantle...
or (because of the complexity of that name) Moho. According to Mohorovičić, a layered structure would explain the observation of depths where seismic waves change speed and the difference in chemical composition between rocks from the crust and those from the mantle. From the data, he estimated the thickness of the upper layer (crust) to be 54 km. We know today that the crust is 5–9 km below the ocean
Ocean
An ocean is a major body of saline water, and a principal component of the hydrosphere. Approximately 71% of the Earth's surface is covered by ocean, a continuous body of water that is customarily divided into several principal oceans and smaller seas.More than half of this area is over 3,000...
floor and 25–60 km below the continent
Continent
A continent is one of several very large landmasses on Earth. They are generally identified by convention rather than any strict criteria, with seven regions commonly regarded as continents—they are : Asia, Africa, North America, South America, Antarctica, Europe, and Australia.Plate tectonics is...
s, which are carried on tectonic plates.
Subsequent study of the Earth's interior
Structure of the Earth
The interior structure of the Earth, similar to the outer, is layered. These layers can be defined by either their chemical or their rheological properties. The Earth has an outer silicate solid crust, a highly viscous mantle, a liquid outer core that is much less viscous than the mantle, and a...
confirmed the existence of the discontinuity under all continents and oceans. 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
Energy
In physics, energy is an indirectly observed quantity. It is often understood as the ability a physical system has to do work on other physical systems...
of the wind, hail defence and other related elements of the geological body of knowledge known as geoscience.
Mohorovičić retired in 1921. Crater Mohorovičić
Mohorovicic (crater)
Mohorovičić is a lunar impact crater that is located on the far side of the Moon. It lies to the southwest of the larger crater Doppler and the huge walled plain Korolev. To the southwest is a small lunar mare that has been named Lacus Oblivinis....
(on the Moon
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...
's far side) is named in his honour. A Gymnasium
Gymnasium (school)
A gymnasium is a type of school providing secondary education in some parts of Europe, comparable to English grammar schools or sixth form colleges and U.S. college preparatory high schools. The word γυμνάσιον was used in Ancient Greece, meaning a locality for both physical and intellectual...
in Rijeka
Rijeka
Rijeka is the principal seaport and the third largest city in Croatia . It is located on Kvarner Bay, an inlet of the Adriatic Sea and has a population of 128,735 inhabitants...
, Croatia and a school ship in the Croatian Navy are named after him, as was (in 1996) asteroid
Asteroid
Asteroids are a class of small Solar System bodies in orbit around the Sun. They have also been called planetoids, especially the larger ones...
8422 Mohorovičić
8422 Mohorovicic
8422 Mohorovičıć is an asteroid named after Croatian scientist Andrija Mohorovičić.Its orbital period is 5 years and 38 days. It was discovered on December 5, 1996 from Farra d'Isonzo .-External links:...
.