Proceedings of the 12th International INQUA meeting on paleoseismology, active tectonic and archaeoseismology

140 PATA Days 2024 1971; Weber & Cotton, 1980; Phillip et al., 1992) (Fig. 1b). The type of collapse and degradation of thrust fault scarps also depend on other controlling factors, such as the ramp angle, hanging wall composition, type of fault slip, climate, topography, etc. If the thrust tip rolls over the footwall, it may give rise to a suite of landforms with systematic/non-systematic extensional fractures and local collapse phenomena at the hanging wall, namely pressure ridges (Phillip et al., 1992), tank-tread (Yeats et al., 1997), or bulldozing scarps (Kelson et al. (2001) (Fig. 1c). These scarp types could be driven by simple thrusts, or combined with backthrusting and strike-slip movements. They result from surface rupture and may give rise to rupture- related deposits, namely colluvial wedges sensu stricto, or scarp-derived deposits. A different scenario arises when the thrust tip line does not reach the surface and/or flattens out below it. These blind thrusts also give rise to monocline-like scarps, but the fold surface does not disrupt layers above the tip line and the lithofacies assemblage at the thrust deformation zone differs from those derived from emergent thrusting. Such scarps can be named fold-related scarps and may result from a simple propagating ramp (fault-propagation or fault-bend folding) (Fig. 1d) or from wedge thrusting, where passive back thrusting develops (Fig. 1e). Blind thrusts commonly do not lead to hanging-wall gravitational collapse and classical colluvial wedges in the sense described by (Nelson, 1992) do not develop in the thrust deformation zone. According to analog and mechanical models, other processes also seem to shape the lithofacial architecture at the thrust zone, like lateral mass transfer as the thrust propagates (Takao et al., 2015; Chiama et al., 2023). Coseismic scarp-derived deposits can certainly be present, but they may not be characterized by a wedge-shaped geometry and do not necessarily exhibit a colluvial fabric. They may rather result in a tabular array, overlying both hanging and foot walls, tending to be thicker above the latter. The blind or emergent character of a single thrust trace (and therefore the type of scarp and derived deposits) may vary through time, particularly in those active depositional settings where relationships between sedimentation, erosion, and fault slip rate are not steady. C O N C L U S I O N S It is considered useful to discriminate scarps derived fromQuaternary-activethrustingbetweenthoseresulting from emergent thrusts (overhanging scarps) from those led by shallow blind thrusting (fold-related scarps). The first type may vary from non-collapsed (simple thrust) scarps to different degrees of hanging- wall collapse- related landforms or bulldozing effects (pressure ridges, backthrust pressure ridges, mole tracks). The fold- related landforms could be driven by a single blind thrust ramp or by flat-lying faults (wedge thrusting). Metric- scale wedge thrusting might be an under-represented situation in trench descriptions. Morphologies of fold- related scarps may depict the front limb geometry, but surface ruptures and classical colluvial wedge deposits do not develop under these scenarios. Identifying the linkage among the blind or emergent character of thrusting, the type of thrust scarp developed, and the nature of the resulting lithofacial assemblages derived may provide useful insights to unravel the coseismic or interseismic nature of the scarp- derived deposits (i. e. tectonic vs climatic interplay). A C K N O W L E D G E M E N T S Fruitful discussions of different field cases with many colleagues are truly acknowledged.