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Present‐day crustal thinning in the southern and northern Tibetan Plateau revealed by GPS measurements
Author(s) -
Ge WeiPeng,
Molnar Peter,
Shen ZhengKang,
Li Qiang
Publication year - 2015
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2015gl064347
Subject(s) - geology , thinning , plateau (mathematics) , crust , extensional definition , geodesy , seismology , tectonics , paleontology , geography , mathematical analysis , mathematics , forestry
GPS measurements from sites within the Tibetan Plateau show not only east‐southeast‐west‐northwest extension but also, more importantly, horizontal dilation throughout the interior of the plateau. Assuming conservation of volume, vertical (thinning) strain rates equal horizontal dilation rates, and they, 8.9 ± 0.8 nanostrain a −1 and 7.4 ± 1.2 nanostrain a −1 in northern and southern Tibet, and 12.0 ± 3.2 nanostrain a −1 in its southwestern part, suggest no measureable difference. Principal extensional strain rates also are similar in magnitude and orientation. If crustal thinning began at 10–15 Ma and the current rates of horizontal dilation applied both to the entire crust and to that period, the crust should have thinned by 5.5–8.5 km. If isostatic equilibrium applied, the mean elevation of the plateau would have dropped ~1 km. The similar rates for northern, southern, and southwestern Tibet suggest that the processes dictating crustal extension, normal faulting, and crustal thinning in the three regions differ little from one another.