In large parts of Central Asia, written records of strong earthquakes cover only a few hundred years. However, severe earthquakes are usually rare, so we often lack a detailed understanding of regional tectonics and fault activity. Geological archives, on the other hand, allow insights into seismic events that are much older. In our latest publication in Tectonics, we report on an extremely strong earthquake that struck the Kazakh-Chinese border region about 2000-4000 years ago. It is possible that two fault systems ruptured in one quake, the Dzhungarian and Lepsy faults. The quake had a magnitude of up to M8.4. Even today, offsets of 6-20 m can be found in the landscape.
To track down this quake, we analysed satellite data and carried out extensive mapping in the field. Offset river terraces and scarp degradation analyses allowed dating of the event.
This work was done in an international collaboration led by Oxford University.
Tsai, C. H., Abdrakhmatov, K., Mukambayev, A., Elliott, A. J., Elliott, J. R., Gruetzner, C., Rhodes, E. J., Ivester, A. H., Walker, R. T., & Wilkinson, R. (2022). Probing the Upper End of Intra‐continental Earthquake Magnitude: A Prehistoric Example from the Dzhungarian and Lepsy Faults of Kazakhstan. Tectonics, e2022TC007300.