ResearchWorks Archive

Active tectonics in the central Tien Shan, Kyrgyz Republic

Show simple item record Thompson, Stephen C., 1970- en_US 2009-10-06T16:37:15Z 2009-10-06T16:37:15Z 2001 en_US
dc.identifier.other b46440719 en_US
dc.identifier.other 48660742 en_US
dc.identifier.other Thesis 50598 en_US
dc.description Thesis (Ph. D.)--University of Washington, 2001 en_US
dc.description.abstract Fault slip rates show that late Quaternary contraction is distributed across the Kyrgyz central Tien Shan, and not concentrated at its margins. Nearly every intermontane basin contains Neogene and Quaternary syntectonic strata deformed by Holocene north-south shortening on thrust and reverse faults. In a region that spans almost two-thirds of the north-south width of the central Tien Shan, slip rates on eight faults in five basins range from ∼0.1 to ∼3 mm/yr. Fault slip rates come from faulted and folded river terraces and from trench-wall exposures. Radiocarbon, infrared-stimulated luminescence, and thermoluminescence ages limit ages of terraces and aid in their regional correlation. A major episode of regional river incision occurred ∼13.5--15.7 x 103 cal yr B.P., coincident with abrupt warming of global climate at the end of the last glacial period. The penultimate major river incision occurred ∼141 ka, coincident with the end of the penultimate glacial period. The sum of late Quaternary rates of shortening resembles current rates of north-south shortening measured using Global Positioning System (GPS) geodesy since 1992. This similarity suggests that deformation is concentrated along major fault zones near range-basin margins. Such faults, separated by essentially rigid blocks, accommodate most of the shortening in the upper crust.Paleoseismic data from offset river terraces and trench exposures of faults in the northern foreland and intermontane basins provide evidence ∼2--4 m of displacement during earthquakes, and include a ∼3.5 m displacement from the 1885 M ≈ 6.9 Byelovoda earthquake. The range of displacement is similar to the observed surface displacement after the 1992 Ms = 7.3 Suusamyr earthquake. A preliminary source map of high slip-rate faults across the Kyrgyz central Tien Shan indicates that a 2--4 m event should occur every 60--70 years. This result is generally consistent with the historical record. en_US
dc.format.extent ix, 141 p. en_US
dc.language.iso en_US en_US
dc.rights Copyright is held by the individual authors. en_US
dc.rights.uri en_US
dc.subject.other Theses--Geology en_US
dc.title Active tectonics in the central Tien Shan, Kyrgyz Republic en_US
dc.type Thesis en_US

Files in this item

This item appears in the following Collection(s)

Show simple item record

Search ResearchWorks

Advanced Search


My Account