Tonie Marie van Dam (born April 19, 1960) is an American geophysicist and geodesist, known for her pioneering research on solid Earth deformations due to loads from atmospheric and hydrologic pressures. She and her collaborators used space geodetic observations and modeling for increased precision in measuring and understanding such loads. [1]
Tonie van Dam graduated in 1982 with a B.S. in physics and geology from Mary Washington College (now renamed the University of Mary Washington). At the University of Colorado Boulder, she graduated in 1991 with a Ph.D. in geophysics. Her Ph.D. thesis Atmospheric Load Response of the Solid Earth and Oceans [2] was supervised by John M. Wahr. [1] From 1991 to 1993 she was a postdoc at Massachusetts Institute of Technology (MIT). From 1993 to 2000 she worked for the U.S. civil service as a research geophysicist at the Geosciences Laboratory of the National Geodetic Survey (part of the National Oceanic and Atmospheric Administration). In the Faculté des Sciences, de la Technologie et de la Communication at the University of Luxembourg, she was an associate professor from 2006 to 2013 and a full professor from 2013 to 2019. (In language skills, she has functional ability in French and basic skills in both Luxembourgish and Spanish.) [2] In 2020 she was appointed to a full professorship in the University of Utah's Department of Geology and Geophysics.
Van Dam is the author or coauthor of more than 120 publications. [3] Her research focuses on the geodesy and geophysics of loads from atmospheric and hydrologic pressures. [4] [5] [6] [7] [8] [9] [10] Her 2001 article Crustal displacements due to continental water loading (written with six collaborators, including John M. Wahr, Geoffrey Blewitt, and Kristine M. Larson) [11] is considered a classic in geodesy. [1] [3] [12] Van Dam has served the community of geophysicists and geodesist in several capacities and since 2019 is a member of the board of directors of UNAVCO. She is an associate editor for the Institute of Geophysics of the Czech Academy of Sciences's Studia Geophysica et Geodaetica from 2010 to the present and for the International Association of Geodesy's Journal of Geodesy from 2015 to the present. [2]
In 2017 van Dam was awarded Luxembourg's Grand Prix en Sciences de l’Institut Grand-ducal, Science Geologiques/Prix Feidt. [2] The American Geophysical Union (AGU) in 2017 appointed her the Bowie Lecturer [13] and in 2020 elected her a Fellow of the AGU. [12] She received in 2019 the European Geosciences Union’s Vening Meinesz Medal. [1]
Geodesy or geodetics is the science of measuring and representing the geometry, gravity, and spatial orientation of the Earth in temporally varying 3D. It is called planetary geodesy when studying other astronomical bodies, such as planets or circumplanetary systems. Geodesy is an earth science and many consider the study of Earth's shape and gravity to be central to that science. It is also a discipline of applied mathematics.
The geoid is the shape that the ocean surface would take under the influence of the gravity of Earth, including gravitational attraction and Earth's rotation, if other influences such as winds and tides were absent. This surface is extended through the continents. According to Gauss, who first described it, it is the "mathematical figure of the Earth", a smooth but irregular surface whose shape results from the uneven distribution of mass within and on the surface of Earth. It can be known only through extensive gravitational measurements and calculations. Despite being an important concept for almost 200 years in the history of geodesy and geophysics, it has been defined to high precision only since advances in satellite geodesy in the late 20th century.
In satellite laser ranging (SLR) a global network of observation stations measures the round trip time of flight of ultrashort pulses of light to satellites equipped with retroreflectors. This provides instantaneous range measurements of millimeter level precision which can be accumulated to provide accurate measurement of orbits and a host of important scientific data. The laser pulse can also be reflected by the surface of a satellite without a retroreflector, which is used for tracking space debris.
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. 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.
The International Terrestrial Reference System (ITRS) describes procedures for creating reference frames suitable for use with measurements on or near the Earth's surface. This is done in much the same way that a physical standard might be described as a set of procedures for creating a realization of that standard. The ITRS defines a geocentric system of coordinates using the SI system of measurement.
The vertical deflection (VD) or deflection of the vertical (DoV), also known as deflection of the plumb line and astro-geodetic deflection, is a measure of how far the gravity direction at a given point of interest is rotated by local mass anomalies such as nearby mountains. They are widely used in geodesy, for surveying networks and for geophysical purposes.
The Journal of Geophysical Research is a peer-reviewed scientific journal. It is the flagship journal of the American Geophysical Union. It contains original research on the physical, chemical, and biological processes that contribute to the understanding of the Earth, Sun, and Solar System. It has seven sections: A, B, C (Oceans), D (Atmospheres), E (Planets), F, and G (Biogeosciences). All current and back issues are available online for subscribers.
In geodesy and astrometry, earth orientation parameters (EOP) describe irregularities in the rotation of planet Earth. EOP provide the rotational transform from the International Terrestrial Reference System (ITRS) to the International Celestial Reference System (ICRS), or vice versa, as a function of time.
UNAVCO was a non-profit university-governed consortium that facilitated geology research and education using geodesy.
The Lwandle plate is one of three tectonic microplates, along with the Rovuma plate and Victoria plate, that make up the African plate with the Somali plate and the Nubian plate. Its discovery is very recent, so the velocity of the plate is neither well known nor well understood. Many experiments are ongoing to quantify this. The Lwandle plate lies between 30°E and 50°E, sharing a boundary with the Nubian, Somali, and Antarctic plates.
Kelin Wang is a senior research scientist and has worked for the Geological Survey of Canada since 1992. His research encompasses geodynamics and natural hazards, with major contributions in researching slow-slip events along the Cascadia subduction interface.
Juliet J. Biggs is a British geologist who is Professor of Earth Sciences at the University of Bristol. Her research uses satellite geodesy and interferometric synthetic-aperture radar (InSAR) to understand the physics of the Earth's crust. She was awarded the American Geophysical Union John Wahr Award in 2017 and a European Research Council (ERC) consolidator grant in 2020.
Seth Avram Stein is an American geophysicist who has done research in plate tectonics, seismology, and space geodesy. He has also done work in public policy for coping with earthquake hazards.
Richard G. Gordon is an American geophysicist, known for his research on global tectonics, including global plate motions and palaeomagnetism. He is noteworthy for leading two global plate motion projects: NUVEL and MORVEL. In the geosciences, NUVEL and MORVEL are standard models for global plate motions.
Thomas A. Herring is a geophysicist, known for developing and applying systems of space geodesy to high-precision geophysical measurements and geodynamic research.
The Vening Meinesz Medal is an annual award for outstanding research in geodesy.
Ivan Istvan Mueller was a Hungarian-American geodesist and professor at Ohio State University, a leading training center for geodesy in the USA.
John Matthew Wahr was an American geophysicist and geodesist, known for his research on Earth's rotation, Earth tides, ocean tides, post-glacial rebound, and other topics in the geosciences.
Susanna Zerbini is an Italian geophysicist, geodesist, and geodynamicist. She is known as a pioneer in developing and applying satellite geodesy for research in geodynamics and Earth system sciences.
EarthScope Consortium is a 501(c)(3) nonprofit geophysical science support organization. EarthScope Consortium operates two of the National Science Foundation's (NSF) major research facilities, the NSF Geodetic Facility for the Advancement of Geoscience (GAGE) and the NSF Seismological Facility for the Advancement of Geoscience (SAGE), which provide geophysical instrumentation, data access, and services to support geoscience research and education.