skip to main content

DOE PAGESDOE PAGES

Title: The Pingding segment of the Altyn Tagh Fault (91 °E): Holocene slip-rate determination from cosmogenic radionuclide dating of offset fluvial terraces

Morphochronologic slip-rates on the Altyn Tagh Fault (ATF) along the southern front of the Pingding Shan at ~90.5°E are determined by cosmogenic radionuclide (CRN) dating of seven offset terraces at two sites. The terraces are defined based upon morphology, elevation and dating, together with fieldwork and high-resolution satellite analysis. The majority of the CRN model ages fall within narrow ranges (<2 ka) on the four main terraces (T1, T2, T3 and T3′), and allow a detailed terrace chronology. Bounds on the terrace ages and offsets of 5 independent terraces yield consistent slip-rate estimates. The long-term slip-rate of 13.9 ± 1.1 mm/yr is defined at the 95% confidence level, as the joint rate probability distribution of the rate derived from each independent terrace. It falls within the bounds of all the rates defined on the central Altyn Tagh Fault between the Cherchen He (86.4°E) and Akato Tagh (~88°E) sites. This rate is ~10 mm/yr less than the upper rate determined near Tura at ~87°E, in keeping with the inference of an eastward decreasing rate due to progressive loss of slip to thrusts branching off the fault southwards but it is greater than the 9 ± 4 mm/yr rate determined at ~90°Emore » by GPS surveys and other geodetic short-term rates defined elsewhere along the ATF. Furthermore, whether such disparate rates will ultimately be reconciled by a better understanding of fault mechanics, resolved transient deformations during the seismic cycle or by more accurate measurements made with either approach remains an important issue.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6] ;  [7]
  1. Newcastle Univ. (United Kingdom)
  2. Univ. de Strasbourg, Strasbourg Cedex (France)
  3. Nanyang Technological Univ. (Singapore); Institut de Physique du Globe de Paris, Paris (France)
  4. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  5. Univ. of California, Berkeley, CA (United States)
  6. ISTerre, Grenoble Cedex (France)
  7. Central Earthquake Administration, Beijing (China)
Publication Date:
OSTI Identifier:
1245708
Report Number(s):
LLNL-JRNL--566181
Journal ID: ISSN 0148-0227
Grant/Contract Number:
AC52-07NA27344
Type:
Accepted Manuscript
Journal Name:
Journal of Geophysical Research
Additional Journal Information:
Journal Volume: 117; Journal Issue: B9; Journal ID: ISSN 0148-0227
Publisher:
American Geophysical Union
Research Org:
Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES beryllium-10; strike-slip fault slip-rate; Altyn Tagh Fault; Asia; Continental deformation; early holocene optimum