George Plafker

from Wikipedia, the free encyclopedia

George Plafker (born March 6, 1929 in Upland (Pennsylvania) ) is an American geologist and geophysicist .

Plafker graduated from Brooklyn College with a bachelor's degree in 1949 and the University of California, Berkeley , with a master's degree in 1956 and received his doctorate in geology and geophysics from Stanford University in 1972 . In between, he was an engineering geologist for the US Corps of Engineers in the Sacramento district in 1949/50 and at the US Geological Survey (USGS) from 1951 to 1956, initially in the Department of Military Geology and from 1952 in the Department of Alaska (headquarters was the same as for the whole of western District at that time in Menlo Park ). From 1956 to 1962 he was a petroleum geologist for Standard Oil of California in Bolivia and Guatemala, among others. From 1962 until his retirement in 1995, he was a research geologist with the US Geological Survey. After that he was a consulting engineer geologist.

He dealt with earthquake hazards in Alaska ( tsunamis , landslides ), the connection between tectonic deformation and large earthquakes (with observations in Alaska, Central and South America), oil deposits in the Gulf of Alaska and neighboring offshore areas, the deep crustal structure of Alaska and engineering geology . In the analysis of large earthquakes in Alaska ( Good Friday quake 1964 ) and in Chile in the 1960s (such as the Valdivia earthquake in 1960 ), he found indications of their causes in subduction zones in the early days of plate tectonics . When the Alaska quake of March 27, 1964, with a magnitude of 9.2 on the Richter scale, the largest recorded earthquake in US history, Plafker was at a regional conference of the Geological Society of America in Seattle (he felt nothing himself, colleagues in the Space Needle but the long oscillations typical of large earthquakes) and was immediately sent to the earthquake area with his USGS colleagues Art Grantz and Reuben Kachadoorian . At that time, like his companions, he was not an earthquake specialist, but a field geologist with experience in Alaska. After a week of on-site field studies, they returned and issued the preliminary report (Circular 491) that planned the more intensive research in the summer. In particular, the extensive land uplifts and subsidence were included and the results were incorporated into a Science paper from 1965. The areas of large uplift and subsidence were clearly separated by a 800 km long fault line on the sea floor parallel to the Aleutian Trench and were a clear indication of plate subduction as the cause - the Pacific plate was pushed in the Aleutian Trench under Alaska. Previously the preferred explanation was that of a horizontal counterclockwise rotation of the Pacific plate against the North American plate. They were later classified as splay faults along a fault line that reached deep into the subduction plane, and along which Alaska performed a vertical twisting movement in relation to the Pacific foreland, during which the hinterland was lowered, but where the fault occurred but caused an uplift on the sea floor, which Plafker made particularly clear when investigating the uplift of Montague Island . Large subsidence occurred on the other side of the fault line to the Pacific. By examining the regional geology, Plafker found that the observed deformation behavior was also reflected in the earthquakes and tectonic movements of the past. The violence of the earthquake, impressively documented by Plafker and colleagues, made the public in the USA aware of the dangers of earthquakes and vividly illustrated their plate tectonic causes. Soon afterwards, he subjected the Chile earthquake of 1960 with a magnitude of 9.5 to a new analysis and after studies along over a thousand kilometers of coastline on site, he and colleagues came to a similar explanation to the Alaskan earthquake ( megathrust quake ).

In 2017 he received the Penrose Medal . In 1967 he received the Harry Oscar Wood Award in Seismology and in 2017 the Harry Fielding Reid Medal from the Seismological Society of America and in 1979 the Distinguished Service Award from the US Department of the Interior. He is a member of the American Association for the Advancement of Science .

He has been married since 1949 and has three children.

Fonts (selection)

  • Tectonic deformation associated with the 1964 Alaska earthquake, Science, Volume 148, 1965, pp. 1675-1687
  • Tectonics of the March 27, 1964, Alaska Earthquake: US Geol. Surv. Prof. Paper 543 – I, 1969 (74 pages)
  • with JC Savage: Mechanism of the Chilean Earthquakes of May 21 and 22, 1960, Bulletin of the Geological Society of America, No. 81/4, April 1970, pp. 1001-1030
  • The Alaskan earthquake of 1964 and Chilean earthquake of 1960; Implications for arc tectonics and tsunami generation, J. Geophys. Res., Vol. 77, 1972, pp. 901-925.
  • Tectonic aspects of the Guatemala earthquake of Feb. 4, 1976, Science, Volume 193, 1976, pp. 1201-1208.
  • with HC Berg (Ed.): The geology of Alaska, Geological Society of America, The Geology of North America, Volume G 1, Boulder 1994, therein by Plafker:
    • with HC Berg: An overview over the geology and tectonic structure of Alaska, pp. 989-1021
    • with LM Gilpin, JC Lahr: Neotectonic map of Alaska, scale 1: 2.5 million
    • with JC Moore, GR Winkler: Geology of the Southern Alaska Margin, pp. 389-449

Web links

Individual evidence

  1. ↑ Life and career data according to American Men and Women of Science , Thomson Gale 2004.
  2. ↑ Andrew Alden, 50 Years Ago, Alaskan Earthquake Was Key Event for Earth Science, KQED Science, March 27, 2014
  3. ^ Circular 491, USGS
  4. ↑ Marc Pitzke, Alaska Disaster 1964. The Quake That Woke America , Spiegel Online, March 27, 2014
  5. ↑ George Plafker wins top honor in seismology , Eureka Alert, May 11, 2017
personal data
SURNAME Plafker, George
BRIEF DESCRIPTION American geologist and geophysicist
DATE OF BIRTH March 6, 1929
PLACE OF BIRTH Upland, Pennsylvania