The Altyn Tagh fault (ATF) is one of the most important structures in
the India-Eurasia collision and earth scientists often cite it when discussing
the behavior of large strike-slip faults, however little is known about its
earthquake geology and history. To address this irony, we documented the fault
trace geometry, magnitude of surface offsets, and timing of recent earthquakes
to reconstruct the earthquake history of the central ATF for the last ~3000
years. Our data indicate that the central ATF produces moderate to large earthquakes,
but is presently not as active as either the San Andreas or North Anatolia
faults. The results of this work address the current discrepancy between geologic
(~30 mm/yr), and geodetic (~10 mm/yr) estimates of slip rate. This discrepancy
may result from changes in long term loading rate (e.g., southward migration
of deformation to structures such as the Kunlun fault).
The following pages are divided into three sections (geometry, geomorphic offsets, paleoseismology) and show the results of three years of study along the central Altyn Tagh fault by Zack Washburn (ECI), and J Ramón Arrowsmith.
Fault Trace Geometry