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JOURNAL OF GEOPHYSICAL RESEARCH,
VOL. 110,
B06402,
doi:10.1029/2003JB002603,
2005
Irregular earthquake cycle along the southern Tianshan front, Aksu area, China
Aurélia Hubert-Ferrari
Institut de Géologie, Université de Neuchatel, Neuchâtel, Switzerland Department of Geosciences, Princeton University, Princeton, New Jersey, USA
John Suppe
Department of Geosciences, Princeton University, Princeton, New Jersey, USA
Jerome Van Der Woerd
Institut de Physique du Globe de Strasbourg, CNRS UMR 7516, Strasbourg, France
Xin Wang
Geosciences Department, Zhejiang University, Hangzhou, China
Huafu Lu
Department of Earth Sciences, Nanjing University, Nanjing, China
Abstract
A long deformation record (∼16.5 ka) showing nonsteady earthquake recurrence is established for the Aksu thrust (Tianshan,
China) on the basis of cosmogenic 10Be dating of faulted surfaces. Topographic leveling across the Aksu fault scarp indicates up to ∼10 m uplift across a moraine
abandoned ∼16.5 ka and similar uplift of ∼6 m across two inset surfaces yielding ages of ∼12.5 and ∼5 ka. Successively smaller
uplifts of terraces younger than 5 ka indicate that three or more major earthquakes occurred during this period. These data
show that the Aksu thrust fault was quiet for at least 7500 years and active in the last ∼5000 years and probably in the interval
16.5–12.5 ka. The seismic cycle along the Aksu thrust fault over the last ∼16,500 years was thus strongly irregular showing
long quiescence and clustering, which is a challenge for paleoseismology and hazard assessment. This irregularity also makes
it more difficult to estimate long-term shortening rates. Nevertheless, we are able to constrain a minimum total shortening
rate (>7 mm/yr) across the southern Tianshan front for the last 12,500 years that is about a third of the total geodetic rate
for the western Tianshan (∼20 mm/yr).
Received 28
May
2003;
accepted 1
February
2005;
published 11
June
2005.
Keywords: Tianshan;
thrust faulting;
seismic cycle.
Index Terms: 8123 Tectonophysics: Dynamics: seismotectonics; 8158 Tectonophysics: Plate motions: present and recent (3040); 8178 Tectonophysics: Tectonics and magmatism.
Read Full Article (file size: 2301099 bytes) Cited by
Citation: Hubert-Ferrari, A., J. Suppe, J. Van Der Woerd, X. Wang, and H. Lu
(2005),
Irregular earthquake cycle along the southern Tianshan front, Aksu area, China,
J. Geophys. Res.,
110,
B06402,
doi:10.1029/2003JB002603.
Copyright 2005 by the American Geophysical Union.
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