Thèse la Sismicité et la Tectonique Active Ont-Elles Influencé les Migrations des Hominidés en Asie Centrale Depuis la Fin du Pléistocène le Cas du Nord du Tien Shan H/F - Doctorat.Gouv.Fr

Établissement : Université Grenoble Alpes École doctorale : STEP - Sciences de la Terre de l'Environnement et des Planètes Laboratoire de recherche : Institut des Sciences de la Terre Direction de la thèse : Pascale HUYGHE ORCID 000000034463506X Début de la thèse : 2026-10-01 Date limite de candidature : 2026-05-15T23:59:59 Active tectonics have a lasting influence on landscapes and constitute a major factor in the mobility, settlement, and dispersion of human populations. By altering hydrological networks, landforms, and shelter possibilities, seismic activity directly affects settlement conditions on timescales compatible with the evolution of ecosystems and human societies. The proximity of water resources, essential for habitation sites, is particularly sensitive to tectonic deformations, while major earthquakes (Mw 6 to 8) can lead to the destruction of sites and cause population displacements. In orogenic contexts, the interactions between tectonics and climate amplify these effects, with the terrain controlling both precipitation patterns and ecosystem diversity. 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 TalasFergana 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 generalized damages to the cities like Almaty or Bishkek. Specific magnetograms allowed to recover 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 this other hand, Central Asia is positioned at the cross-roads 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 drying up of local springs (e.g. Obi-Rakhmat Grotto archeological 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 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.
Déterminer si les séismes et la dynamique des paysages associée à la tectonique active ont structuré les trajectoires de peuplement humain au Pléistocène supérieur dans le nord de la chaine du Tien Shan. We propose to focus on sites carefully selected in collaboration with Zoostan (Almaty), in the ages range of 80 to 3 kyr. The idea is to analyze the overall neotectonic features in the vicinity of the targeted sites with classical methodologies such as paleoseismology (detailed sedimentology and dating), quantitative morphotectonics, surface dating, near-surface geophysics (georadar, electric methods, etc.) to characterize the active faults and the related seismicity (size, energy, timing). We will combine this field approach with seismotectonics (relocation of earthquakes, focal mechanisms investigations, stress inversion) and eventually geodetic approaches (GNSS and InSAR).
The tectonic part will be led in parallel with the archeological approach, with sites and caves investigations oriented toward the detection of potential effect of seismicity (sedimentology of the infills, speleothem analysis, dating, archaeometry, etc.). A key-point is to determine if the settlements then abandonments of the caves or rock shelter was sudden or progressive, and potentially related to earthquakes.
If the opportunity arises, we also plan to deploy a temporary seismic nodes network (6 months to 1 year, SISMOB nodes) along one of the most active fault systems we could determine, to better characterize its current activity. That point could represent a sub-project, at the margin of the core topic, but eventually bringing connections with seismologist community in Almaty and Bishkek.

Nous recherchons un(e) candidat(e) très motivé(e) ayant une formation en sciences de la Terre, avec de solides compétences en tectonique. Alternativement, le(a) candidat(e) pourrait avoir une solide formation en archéologie des hominidés, avec des compétences complémentaires en géophysique et en géologie. Le(a) candidat(e) devra être à l'aise avec le travail sur le terrain, en équipe et les collègues issus de divers domaines (sismologie, archéologie, tectonique, etc.), dans le cadre général des laboratoires ISTerre et Zoostan. Il/elle devra montrer un fort intérêt pour la coopération internationale, notamment en Asie centrale. Il/elle doit avoir un haut niveau d'autonomie et une bonne capacité de mobilité dans divers environnements, y compris lors de missions de terrain dans des conditions difficiles. Des compétences en programmation Python ou Matlab sont nécessaires pour la gestion des données. Un bon niveau d'anglais (oral et écrit) est requis.