Donald V. Helmberger
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Donald V. Helmberger
Donald Vincent Helmberger () was an American seismologist; described in his ''Seismological Research Letters'' obituary as "one of the most impactful seismologists to have lived". A memorial issue in ''Earthquake Science'' was published in his honor February 2022. He served as head of the Caltech Seismological Laboratory from 1998 to 2003, and was the Smits Family Professor of Geophysics, Emeritus upon his death. He was named to the National Academy of Sciences in 2004. Helmberger was the first winner of the Inge Lehmann Medal in 1997. Career After earning his Ph.D. in 1967, he worked as a research associate for Massachusetts Institute of Technology, and then as a faculty member at Princeton University. He began working as an assistant professor at Caltech in 1970. He became an emeritus in 2017. Ultra-low velocity zones were discovered by Helmberger in 1995. Following his death, Mike Gurnis Michael Gurnis is the John E. and Hazel S. Smits Professor of Geophysics at the C ...
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Perham, Minnesota
Perham ( ) is a city in Otter Tail County, Minnesota. The population was 3,512 at the time of the 2020 census. History Perham was platted in 1873, and named for Josiah Perham, first president of the Northern Pacific Railway. As the village grew in economic importance, the surrounding township was renamed Perham Township in 1877 and Perham was incorporated in 1881. Geography According to the United States Census Bureau, the city has a total area of , all land. U.S. Route 10 and Minnesota State Highways 78 and 108 are three of the main routes in the community. Demographics 2010 census As of the census of 2010, there were 2,985 people, 1,304 households, and 722 families living in the city. The population density was . There were 1,388 housing units at an average density of . The racial makeup of the city was 94.1% White, 1.1% African American, 0.5% Native American, 0.5% Asian, 0.1% Pacific Islander, 2.3% from other races, and 1.5% from two or more races. Hispanic or Latin ...
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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 activities are focused on the organization and dissemination of scientific information in the interdisciplinary and international fields within the Earth and space sciences. The geophysical sciences involve four fundamental areas: atmospheric and ocean sciences; solid-Earth sciences; hydrologic sciences; and space sciences. The organization's headquarters is located on Florida Avenue in Washington, D.C. History The AGU was established in December 1919 by the National Research Council (NRC) to represent the United States in the International Union of Geodesy and Geophysics (IUGG), and its first chairman was William Bowie of the United States Coast and Geodetic Survey (USCGS). For more than 50 years, it operated as an unincorporated affili ...
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American Seismologists
American(s) may refer to: * American, something of, from, or related to the United States of America, commonly known as the "United States" or "America" ** Americans, citizens and nationals of the United States of America ** American ancestry, people who self-identify their ancestry as "American" ** American English, the set of varieties of the English language native to the United States ** Native Americans in the United States, indigenous peoples of the United States * American, something of, from, or related to the Americas, also known as "America" ** Indigenous peoples of the Americas * American (word), for analysis and history of the meanings in various contexts Organizations * American Airlines, U.S.-based airline headquartered in Fort Worth, Texas * American Athletic Conference, an American college athletic conference * American Recordings (record label), a record label previously known as Def American * American University, in Washington, D.C. Sports teams Soccer * Ba ...
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University Of California, Los Angeles Alumni
A university () is an institution of higher (or tertiary) education and research which awards academic degrees in several academic disciplines. Universities typically offer both undergraduate and postgraduate programs. In the United States, the designation is reserved for colleges that have a graduate school. The word ''university'' is derived from the Latin ''universitas magistrorum et scholarium'', which roughly means "community of teachers and scholars". The first universities were created in Europe by Catholic Church monks. The University of Bologna (''Università di Bologna''), founded in 1088, is the first university in the sense of: *Being a high degree-awarding institute. *Having independence from the ecclesiastic schools, although conducted by both clergy and non-clergy. *Using the word ''universitas'' (which was coined at its foundation). *Issuing secular and non-secular degrees: grammar, rhetoric, logic, theology, canon law, notarial law.Hunt Janin: "The university ...
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People From Perham, Minnesota
A person ( : people) is a being that has certain capacities or attributes such as reason, morality, consciousness or self-consciousness, and being a part of a culturally established form of social relations such as kinship, ownership of property, or legal responsibility. The defining features of personhood and, consequently, what makes a person count as a person, differ widely among cultures and contexts. In addition to the question of personhood, of what makes a being count as a person to begin with, there are further questions about personal identity and self: both about what makes any particular person that particular person instead of another, and about what makes a person at one time the same person as they were or will be at another time despite any intervening changes. The plural form "people" is often used to refer to an entire nation or ethnic group (as in "a people"), and this was the original meaning of the word; it subsequently acquired its use as a plural form of ...
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California Institute Of Technology Faculty
The California Institute of Technology (branded as Caltech or CIT)The university itself only spells its short form as "Caltech"; the institution considers other spellings such a"Cal Tech" and "CalTech" incorrect. The institute is also occasionally referred to as "CIT", most notably in its alma mater, but this is uncommon. is a private research university in Pasadena, California. Caltech is ranked among the best and most selective academic institutions in the world, and with an enrollment of approximately 2400 students (acceptance rate of only 5.7%), it is one of the world's most selective universities. The university is known for its strength in science and engineering, and is among a small group of institutes of technology in the United States which is primarily devoted to the instruction of pure and applied sciences. The institution was founded as a preparatory and vocational school by Amos G. Throop in 1891 and began attracting influential scientists such as George Ellery Ha ...
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2020 Deaths
This is a list of deaths of notable people, organised by year. New deaths articles are added to their respective month (e.g., Deaths in ) and then linked here. 2022 2021 2020 2019 2018 2017 2016 2015 2014 2013 2012 2011 2010 2009 2008 2007 2006 2005 2004 2003 2002 2001 2000 1999 1998 1997 1996 1995 1994 1993 1992 1991 1990 1989 1988 1987 See also * Lists of deaths by day The following pages, corresponding to the Gregorian calendar, list the historical events, births, deaths, and holidays and observances of the specified day of the year: Footnotes See also * Leap year * List of calendars * List of non-standard ... * Deaths by year {{DEFAULTSORT:deaths by year ...
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1938 Births
Events January * January 1 ** The Constitution of Estonia#Third Constitution (de facto 1938–1940, de jure 1938–1992), new constitution of Estonia enters into force, which many consider to be the ending of the Era of Silence and the authoritarian regime. ** state-owned enterprise, State-owned railway networks are created by merger, in France (SNCF) and the Netherlands (Nederlandse Spoorwegen – NS). * January 20 – King Farouk of Egypt marries Safinaz Zulficar, who becomes Farida of Egypt, Queen Farida, in Cairo. * January 27 – The Honeymoon Bridge (Niagara Falls), Honeymoon Bridge at Niagara Falls, New York, collapses as a result of an ice jam. February * February 4 ** Adolf Hitler abolishes the War Ministry and creates the Oberkommando der Wehrmacht (High Command of the Armed Forces), giving him direct control of the German military. In addition, he dismisses political and military leaders considered unsympathetic to his philosophy or policies. Gene ...
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Mike Gurnis
Michael Gurnis is the John E. and Hazel S. Smits Professor of Geophysics at the California Institute of Technology. Gurnis served as director of the Computational Infrastructure for Geodynamics (CIG), an NSF-funded institute operated by Caltech which supports and promotes Earth science by developing and maintaining open-source software for computational geophysics and related fields. Gurnis was awarded the 2013 Agustus Love Medal for fundamental contributions to geodynamics from the European Geosciences Union The European Geosciences Union (EGU) is a non-profit international union in the fields of Earth, planetary, and space sciences whose vision is to "realise a sustainable and just future for humanity and for the planet." The organisation has headq .... External links Michael Gurnis' Caltech Home PageMichael Gurnis' 2013 Augustus Love Medal citation California Institute of Technology faculty Living people Year of birth missing (living people) {{US-academic-stub ...
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Phys
Physics is the natural science that studies matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge which relates to the order of nature, or, in other words, to the regular succession of events." Physics is one of the most fundamental scientific disciplines, with its main goal being to understand how the universe behaves. "Physics is one of the most fundamental of the sciences. Scientists of all disciplines use the ideas of physics, including chemists who study the structure of molecules, paleontologists who try to reconstruct how dinosaurs walked, and climatologists who study how human activities affect the atmosphere and oceans. Physics is also the foundation of all engineering and technology. No engineer could design a flat-screen TV, an interplanetary spacecraft, or even a better mousetrap without first understanding the basic laws of physics. (. ...
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Ultra Low Velocity Zone
Ultra low velocity zones (ULVZs) are patches on the core-mantle boundary that have extremely low seismic velocities. The zones are mapped to be hundreds of kilometers in diameter and tens of kilometers thick. Their shear wave velocities can be up to 30% lower than surrounding material. The composition and origin of the zones remain uncertain. The zones appear to correlate with edges of the African and Pacific Large low-shear-velocity provinces (LLSVPs) as well as the location of hotspots. Discovery and constraints ULVZs are discovered by the delay and scattering of body waves that reflect and diffract on or are refracted by the core-mantle boundary. Different body waves types give different constraints on the dimensions or velocity contrasts of the ULVZ. Even though ULVZs are discovered in places, it remains difficult to map out their extent and constrain their density and velocity. Usually trade-offs between various parameters exist. In general though, ULVZs appear to be a h ...
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Caltech
The California Institute of Technology (branded as Caltech or CIT)The university itself only spells its short form as "Caltech"; the institution considers other spellings such a"Cal Tech" and "CalTech" incorrect. The institute is also occasionally referred to as "CIT", most notably in its alma mater, but this is uncommon. is a private university, private research university in Pasadena, California. Caltech is ranked among the best and most selective academic institutions in the world, and with an enrollment of approximately 2400 students (acceptance rate of only 5.7%), it is one of the world's most selective universities. The university is known for its strength in science and engineering, and is among a small group of Institute of Technology (United States), institutes of technology in the United States which is primarily devoted to the instruction of pure and applied sciences. The institution was founded as a preparatory and vocational school by Amos G. Throop in 1891 and began ...
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