Adam Marian Dziewoński (November 15, 1936 – March 1, 2016) was a Polish-American

geophysicist Geophysics () is a subject of natural science concerned with the physical processes and physical properties of the Earth and its surrounding space environment, and the use of quantitative methods for their analysis. The term ''geophysics'' som ...

who made seminal contributions to the determination of the large-scale structure of the

Earth's interior The internal structure of Earth is the solid portion of the Earth, excluding its atmosphere and hydrosphere. The structure consists of an outer silicate solid crust, a highly viscous asthenosphere and solid mantle, a liquid outer core whose ...

and the nature of

earthquakes An earthquake (also known as a quake, tremor or temblor) is the shaking of the surface of the Earth resulting from a sudden release of energy in the Earth's lithosphere that creates seismic waves. Earthquakes can range in intensity, fro ...

using seismological methods. He spent most of his career at

Harvard University Harvard University is a private Ivy League research university in Cambridge, Massachusetts. Founded in 1636 as Harvard College and named for its first benefactor, the Puritan clergyman John Harvard, it is the oldest institution of highe ...

, where he was the Frank B. Baird, Jr. Professor of Science.

Life and main scientific contributions

Dziewonski was born in

Lwów Lviv ( uk, Львів) is the largest city in Western Ukraine, western Ukraine, and the List of cities in Ukraine, seventh-largest in Ukraine, with a population of . It serves as the administrative centre of Lviv Oblast and Lviv Raion, and is o ...

, which was then a part of Poland, currently a part of Ukraine. After having earned a master's degree from the

University of Warsaw The University of Warsaw ( pl, Uniwersytet Warszawski, la, Universitas Varsoviensis) is a public university in Warsaw, Poland. Established in 1816, it is the largest institution of higher learning in the country offering 37 different fields of ...

, Poland (1960), and a Doctorate of Technical Sciences from the Academy of Mines and Metallurgy, Cracow, Poland (1965) Dziewonski taught at the

University of Texas at Dallas The University of Texas at Dallas (UTD or UT Dallas) is a public research university in Richardson, Texas. It is one of the largest public universities in the Dallas area and the northernmost institution of the University of Texas system. It w ...

for several years before settling at Harvard. In the 1960s and 1970s, Dziewonski and his collaborators laid the foundation to understanding the underlying cause of tectonic plate motions by exploring

convection Convection is single or multiphase fluid flow that occurs spontaneously due to the combined effects of material property heterogeneity and body forces on a fluid, most commonly density and gravity (see buoyancy). When the cause of the c ...

currents in the

Earth's mantle Earth's mantle is a layer of silicate rock between the crust and the outer core. It has a mass of 4.01 × 1024 kg and thus makes up 67% of the mass of Earth. It has a thickness of making up about 84% of Earth's volume. It is predominantly so ...

with radial maps of seismic property variations, based on measurements of

seismic waves A seismic wave is a wave of acoustic energy that travels through the Earth. It can result from an earthquake, volcanic eruption, magma movement, a large landslide, and a large man-made explosion that produces low-frequency acoustic energy. ...

. These studies led to the development of the

Preliminary reference Earth model The preliminary reference Earth model (PREM) plots the average of Earth's properties by depth. It includes a table of Earth properties, including elastic properties, attenuation, density, pressure, and gravity. PREM has been widely used as ...

(PREM) in collaboration with

Don Anderson Sir Donald George Anderson (1 March 191730 November 1975) was a senior Australian public servant. He was Director-General of the Department of Civil Aviation from January 1956 until September 1973. Life and career Anderson was born to parent ...

; PREM established an accurate radial model of the Earth for seismic velocities,

attenuation In physics, attenuation (in some contexts, extinction) is the gradual loss of flux intensity through a medium. For instance, dark glasses attenuate sunlight, lead attenuates X-rays, and water and air attenuate both light and sound at var ...

, and

density Density (volumetric mass density or specific mass) is the substance's mass per unit of volume. The symbol most often used for density is ''ρ'' (the lower case Greek letter rho), although the Latin letter ''D'' can also be used. Mathematicall ...

. Starting in the 1980s, Dziewonski led two original and powerful research efforts. He extended the radial Earth models to be fully three-dimensional, along the way mapping and interpreting four "grand" structures. The four include two regions of higher-than-average wavespeed, inferred to be cold and sinking mantle, one under the western edge of the Americas and the other under southern Eurasia. The two other features are large-scale regions of slower-than-average wavespeed, inferred to be hot and rising superplumes, located at the bottom of the mantle under the middle of the Pacific Ocean and Africa. His other research direction systematically determined the orientation and magnitude of the deformation for most of the significant earthquakes that have been well-recorded. These results are known as the Harvard CMTs (centroid moment tensor solutions) and are continued today at

Lamont–Doherty Earth Observatory The Lamont–Doherty Earth Observatory (LDEO) is the scientific research center of the Columbia Climate School, and a unit of The Earth Institute at Columbia University. It focuses on climate and earth sciences and is located on a 189-acre ( ...

by Göran Ekström and Meredith Nettles as the Global CMT Project. Dziewonski received numerous honours and awards for his scientific achievements, among them the Gold Medal of

Ettore Majorana Foundation and Centre for Scientific Culture Ettore Majorana Foundation and Centre for Scientific Culture (acronym EMFCSC) is an scientific organization based in Erice, Sicily (Italy). The President of EMFCSC is Prof. Antonino Zichichi. It sponsors the International School of Subnuclear Phys ...

(1999), the Harry Fielding Reid Medal of the Seismological Society of America (1999), the

Crafoord Prize The Crafoord Prize is an annual science prize established in 1980 by Holger Crafoord, a Swedish industrialist, and his wife Anna-Greta Crafoord. The Prize is awarded in partnership between the Royal Swedish Academy of Sciences and the Crafoord Foun ...

of the Royal Swedish Academy of Sciences (1998), and the Bowie Medal of the

American Geophysical Union The American Geophysical Union (AGU) is a 501(c)(3) nonprofit organization of Earth, atmospheric, ocean, hydrologic, space, and planetary scientists and enthusiasts that according to their website includes 130,000 people (not members). AGU's ...

(2002). In 1995 he was also elected a member of the

United States National Academy of Sciences The National Academy of Sciences (NAS) is a United States nonprofit, non-governmental organization. NAS is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy of Engineering (NAE) and the N ...

.Dziewonski, Adam M. - Member profile.

. Accessed September 12, 2008. He died in

Cambridge, Massachusetts Cambridge ( ) is a city in Middlesex County, Massachusetts, United States. As part of the Boston metropolitan area, the cities population of the 2020 U.S. census was 118,403, making it the fourth most populous city in the state, behind Boston, ...

, on March 1, 2016.

Important publication

* A. M. Dziewonski, D. L. Anderson: Preliminary reference Earth model. ''Physics of the Earth and Planetary Interiors 25, S.297–356 (1981)

References

External links

Dziewonski's webpage at HarvardOral history interview transcript with Adam Dziewonski on 26 January 1994, American Institute of Physics, Niels Bohr Library & ArchivesGlobal Centroid Moment Tensor project
{{DEFAULTSORT:Dziewonski, Adam Marian 1936 births 2016 deaths Seismologists University of Warsaw alumni University of Texas at Austin faculty Harvard University faculty Members of the United States National Academy of Sciences