The Wednesday Centerfault (9) – Altyn Tagh Fault

Quite near my personal working area or, in other words, some hundreds of kilometers away (which I didn’t experience as much of a distance in a huge country like China), the terrific and over 1500 km long Altyn Tagh Fault separates the northern Tibetan Plateau from the Tarim Basin and the Alashan and Alxa blocks. Being a major fault (Fig. 1) that facilitates the eastward squeeze of the thickened crustal structure of the Tibet orogen, the sinistral strike-slip fault shoulders a total displacement of 375-500 km!

Topography of the Tibetan Plateau and adjacent regions with some of the major faults, from Darby et al. (2005)

The Altyn Tagh Fault is active with slip rates of ±10 mm/a, determined by various studies e.g. through field work (8-12 mm/a; Gold et al., 2011), GPS (±10 mm; Zhang et al., 2007) and InSAR (11 ±5 mm; Elliot et al., 2008). The instrumental seismicity record is sparse and no major earthquakes are documented.

Fortunately, a paleoseismologic study has been conducted by Washburn et al. (2003). They trenched and found evidence for 2-3 earthquakes in the last 2-3 kyr and estimante slip rates of 5-10 m per event at the Xorxol segment at the central Altyn Tagh Fault. The last major earthquake hence may have occured between 1456 and 1775 cal. AD, following 14C dating.

Lots of articles are available on that topic!

Fault trace map from Washburn et al., 2003
Trench log from Washburn et al., 2003

References and Further Reading:

Gold, R.D., E. Cowgill, J.R. Arrowsmith, X. Chen, W.D. Sharp, K.M. Cooper, and X. Wang (2011): Faulted terrace risers place new constraints on the late Quaternary slip rate for the central Altyn Tagh fault, northwest Tibet, GSA Bulletin 123, no. 5/6, May/June 2011, pp. 958-978, doi: 10.1130/B30207.1

Elliot, J.R., J. Biggs, B. Parsons, T.J. Wright (2008): InSAR slip rate determination on the Altyn Tagh Fault, northern Tibet in the presence of topographically correlated atmospheric delays, Geophysical Research Letters 35, L12309, doi: 10.1029/2008GL033659.

Zhang, P., P. Molnar, X. Xu (2007): Late Quaternary and present-day rates of slip along the Altyn Tagh Fault, northern margin of the Tibetan Plateau, Tectonics 26, TC5010, doi: 10.1029/2006TC002014.

Darby, B.J., B.D. Ritts, Y. Yue, and Q. Meng (2005): Did the Altyn Tagh fault extend beyond the Tibetan Plateau? Earth and Planetary Science Letters 240, pp. 425-435, doi: 10.1016/j.epsl.2005.09.011.

Washburn, Z., J.R. Arrowsmith, G. Dupont-Nivet, W. Feng, Z. Qiao, and C. Zhengle (2003): Paleoseismology of the Xorxol segment of the central Altyn Tagh Fault, Xinjiang, China, Annals of Geophysics 46, 5, doi: 10.4401/ag-3443.

Tapponnier, P., Z. Xu, F. Roger, B. Meyer, N. Arnaud, G. Wittlinger, and J. Yang (2001): Oblique Stepwise Rise and Growth of the Tibet Plateau, Science 294, 23 November 2001, doi: 10.1126/science.105978.

Leave a Reply

Your email address will not be published. Required fields are marked *