Paleoseismology of the Xorxol Segment of the Central Altyn Tagh Fault, Xinjiang, China

Z. Washburn, J. R. Arrowsmith, G. Dupont-Nivet, W. X. Feng, Z. Y. Qiao, C. Zhengle

Abstract


Although the Altyn Tagh Fault (ATF) is thought to play a key role in accommodating India-Eurasian convergence,
little is known about its earthquake history. Studies of this strike-slip fault are important for interpretation
of the role of faulting versus distributed deformation in the accommodation of the India- Eurasia collision.
In addition, the > 1200 km long fault represents one of the most important and exemplary intracontinental
strike-slip faults in the world. We mapped fault trace geometry and interpreted paleoseismic trench exposures to
characterize the seismogenic behavior of the ATF. We identified 2 geometric segment boundaries in a 270 km
long reach of the central ATF. These boundaries define the westernmost Wuzhunxiao, the Central Pingding, and
the easternmost Xorxol (also written as Suekuli or Suo erkuli) segments. In this paper, we present the results
from the Camel paleoseismic site along the Xorxol Segment at 91.759°E, 38.919°N. There evidence for the last
two earthquakes is clear and 14C dates from layers exposed in the excavation bracket their ages. The most recent
earthquake occurred between 1456 and 1775 cal A.D. and the penultimate event was between 60 and 980 cal
A.D. Combining the Camel interpretations with our published results for the central ATF, we conclude that multiple
earthquakes with shorter rupture lengths (?? 50 km) rather than complete rupture of the Xorxol Segment better
explain the paleoseismic data. We found 2-3 earthquakes in the last 2-3 kyr. When coupled with typical
amounts of slip per event (5-10 m), the recurrence times are tentatively consistent with 1-2 cm/yr slip rates. This
result favors models that consider the broader distribution of collisional deformation, rather than those with
northward motion of India into Asia absorbed along a few faults bounding rigid blocks.

Keywords


paleoseismology;Altyn Tagh Fault;strike-slip faults;India-Eurasia collision

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References


DOI: https://doi.org/10.4401/ag-3443
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Published by INGV, Istituto Nazionale di Geofisica e Vulcanologia - ISSN: 2037-416X