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Full-Text Articles in Geology

Late Quaternary Slip Rates Across The Central Tien Shan, Kyrgyzstan, Central Asia, Stephen C. Thompson, Ray J. Weldon, Charles M. Rubin, Kanatbek Abdrakhmatov, Peter Molnar, Glenn W. Berger Sep 2002

Late Quaternary Slip Rates Across The Central Tien Shan, Kyrgyzstan, Central Asia, Stephen C. Thompson, Ray J. Weldon, Charles M. Rubin, Kanatbek Abdrakhmatov, Peter Molnar, Glenn W. Berger

All Faculty Scholarship for the College of the Sciences

Slip rates across active faults and folds show that late Quaternary faulting is distributed across the central Tien Shan, not concentrated at its margins. Nearly every intermontane basin contains Neogene and Quaternary syntectonic strata deformed by Holocene north‐south shortening on thrust or reverse faults. In a region that spans 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 are derived from faulted and folded river terraces and from trenches. Radiocarbon, optically stimulated luminescence, and thermoluminescence ages limit ages of terraces and …


Whole Mantle Shear Structure Beneath The East Pacific Rise, Timothy I. Melbourne, Donald V. Helmberger Sep 2002

Whole Mantle Shear Structure Beneath The East Pacific Rise, Timothy I. Melbourne, Donald V. Helmberger

All Faculty Scholarship for the College of the Sciences

We model broadband seismograms containing triplicated S, S2, and S3 along with ScS to produce a pure path one‐dimensional model extending from the crust to the core‐mantle boundary beneath the East Pacific Rise. We simultaneously model all body wave shapes and amplitudes, thereby eliminating depth‐velocity ambiguities. The data consist of western North American broadband recordings of East Pacific Rise (EPR) affiliate transform events that form a continuous record section out to 82° and sample nearly the entire East Pacific Rise. The best fitting synthetics contain attenuation and small changes in lithospheric thickness needed to correct for …