Active Tectonics of Central Asia

Neill Marshall, Ian Pierce, Richard Walker, Tamarah King, Shengsue Lei, Zakeria Shnizai, Chia-Hsin Tsai, Roberta Wilkinson, & Ben Johnson

Submitted September 11, 2022, SCEC Contribution #12212, 2022 SCEC Annual Meeting Poster #091

Our efforts are focused on solving earthquake and tectonic problems from Mongolia and China in the east, through to Iran and the Caucasus. We work with local partners, combining research with capacity building efforts and support for early career researchers. Here we demonstrate our ongoing efforts towards 1) understanding earthquake occurrence in continental interiors by combining recent, historic, and palaeoseismic examples, 2) investigating regional distributions of active faults, and unravelling the kinematics and evolution of tectonic regimes, and 3) working with our partners towards increasing resilience to earthquake hazards. The 19th century to mid 20th century earthquakes of central Asia offer a world class insight into the processes of earthquake occurrence and rupture in continental interiors. Using seismological and geomorphic methods, we uncover the sources of the destructive Mw7.4 1949 Khait earthquake in Tajikistan and the Mw7.4 1948 Ashgabat earthquake in Turkmenistan. We use the pristine landscape to investigate the very rare, largest, earthquakes, such as on the Dzhungarian fault in Kazakhstan which shows evidence for a prehistoric earthquake of upto Mw 8.4. An important aim is to define earthquake sources close to cities and critical infrastructure. We demonstrate at least 2 earthquakes in the past 10 kyrs on the Zailisky Rangefront Fault which runs beneath Almaty, Kazakhstan's largest city. Near Dushanbe, the capital of Tajikistan, we combine time series InSAR and tectonic geomorphology to characterize behaviour of the Ilyak fault, which runs through the city. We find it is creeping close to the surface, but its behavior at depth remains uncertain. We are compiling regional active fault maps, and populating these maps with results from fault slip-rate and palaeoseismic studies, with an initial focus on Kazakhstan and Kyrgyzstan. Our Tien Shan database integrates decades of mapping and field-studies from a range of contributors using a three-tiered database structure, which retains variable resolutions (scales) of fault line-mapping for diverse purposes. We are developing detailed fault maps of the Kabul region, Afghanistan, and of Xian in China. Our work in Azerbaijan (onshore and offshore) using combined remote sensing and paleoseismic data reveals highly active faults with destructive earthquake histories that together form a complicated triple-junction plate boundary between the Iranian, Caspian, and Eurasian plates.

Citation
Marshall, N., Pierce, I., Walker, R., King, T., Lei, S., Shnizai, Z., Tsai, C., Wilkinson, R., & Johnson, B. (2022, 09). Active Tectonics of Central Asia. Poster Presentation at 2022 SCEC Annual Meeting.

Related Projects & Working Groups
Earthquake Geology