Did active tectonics and seismicity shape hominid migrations in Central Asia from Late Pleistocene onward? Case studies along the North Tian Shan mountains.

By shaping the landscapes, active tectonics, and notably seismicity, have shaped the patterns of human mobility, settlement, and dispersion, as shown in the East African rift (King & Baley, 2006) and further around the entire Africa (Baley et al., 2011). From a conceptual viewpoint, tectonism interacts with hominid dynamics at first order through their impact on hydrogeological fluxes and shelters opportunities. Dynamic landscapes, under the influence of active faulting (earthquakes), would locally maintain or displace hydrological patterns, within timescales that match the timescales of ecosystems’ evolution, hence the hominid dynamics. The proximity of water sources, rivers, and lakes, is necessary for favorable settlement sites, and their sensitivity to earthquake activity, in particular in the Tian Shan belt (e.g. Poisson & Avouac, 2004; Guerit et al., 2016), connects hominids’ development to tectonics. Beyond that point, in an orogenic context, interaction between climate and tectonics would also modulate the human activity, relief acting as moisture and rain barrier. Last but not least, mountain building, as far as the relief remains moderated, provide a variety of (uplifting) landscapes that would favor food resources diversity (flora and fauna) through the development of altitude ecosystems, and may provide shelter (cliffs, caves). Human occupation sites may be destroyed or damaged by earthquakes, specifically of high Mw (6 to 8). Such large events may thus be responsible for migration of human groups.

This PhD proposal aims to investigate the formal interactions between tectonics (earthquakes, landscape dynamics) and hominid mobility in the frame of Central Asia (e.g. Beeton et al., 2014; Rybin et al., 2015; Namen et al., 2022; Radu et al., 2024). We propose to focus on the North Tian Shan mountains, as this region presents both a high seismotectonic activity (historical and instrumental), recorded by the Kazakh and Kyrgyz seismological networks (e.g. Kalmetieva et al., 2009; Kruger et al., 2028) and a dense corpus of archeological sites studied by archeologist and anthropologist colleagues at the ZooStan institute (Almaty, Kazakhstan) and at the French institute for Central Asia (Bishkek, Kyrgyzstan).

From a geodynamic viewpoint, the Tian Shan is an intracontinental mountain range in Central Asia located to the north of the Tibetan Plateau. It has been strongly reactivated since the Cenozoic due to the collision between the Indian and Eurasian plates (e.g. Molnar and Tapponnier, 1975). Fold and thrust belts along the northern and southern flanks of the Tian Shan have accommodated the propagation of deformation and the widening of the mountain belt (e.g. Avouac et al., 1993; Qiu et al., 2019). The present-day deformation of the belt is still very active, with about 20 mm/yr of horizontal shortening accommodated across the whole Tian Shan belt as seen by GNSS studies (Yang et al., 2008; Zubovich et al., 2010). Most of this shortening is accommodated along reverse E-W and oblique NW-SE right-lateral strike-slip faults such as the Talas‐Fergana Fault (Rizza et al., 2019). The overall fault system in the Tian Shan vicinity regularly produces major earthquakes (Mw in the range of 6 to 8), with generalised damage to cities like Almaty or Bishkek. Specific magnetograms allowed the recovery of the parameters of the 1887 (Verny, Mw 7.7) and 1889 (Chilik, Mw 7.9) (Krüger et al., 2018), located in the North Tian Shan, in the vicinity of the larger 1911 Kemin earthquake (Mw 8.0) (e.g. Nurmagambetov et al., 1999; Kalmetieva et al., 2009). In summary, the study area, to the northern front of the Tian Shan belt, is one of the most seismically active regions in the larger Asia-India collisional system.

On the other hand, Central Asia is positioned at the crossroads between several important zones of hominin settlements and migrations from the Late Pleistocene onward (Finestone et al., 2025). Several sites have been described as abandoned following the drying up of local springs (e.g. Obi-Rakhmat Grotto archaeological site, NW Tien Shan, Baumann et al., 2025). These sites are often located in the vicinity of active faults responsible for historical earthquakes with Mw>6.5 (see Kalmetieva et al., 2009 and Rizza et al, 2019). We can reasonably assume that the recorded tectonic activity is representative of what occurred during the Pleistocene, shaping the overall landscapes of the region. This tectonic activity could have a strong impact on the hominid implantation, and may have triggered their mobility and/or dispersion. This is the core of the project, and the main question we aim to investigate.