How volcanic stratigraphy constrains headscarp collapse scenarios: the Samperre cliff case study (Martinique island, Lesser Antilles)

Abstract. Gravitational instabilities can be significant threats to populations and infrastructure. For hazard assessment, it is important estimate the geometry volume of potential unstable masses. This characterization particularly difficult in volcanic contexts due succession deposition erosion phases. Indeed, results complex layering geometries which interfaces between geological layers may neither parallel nor planar. Geometry all more when masses are located steep hard access landscapes, limits data acquisition. In this work, we show how remote observations used surface envelope an mass on a cliff. We use ortho-photographs, aerial views topographic surveys (i) describe different units cliff, (ii) characterize stability units, (iii) infer paleo-morphology site (iv) volumes. investigate Samperre cliff Martinique (Lesser Antilles, French West Indies) as study site, where recurrent destabilizations since at least 1988 have produced debris flows that threaten Our analysis suggests occurring associated with re-opening paleo-valley filled by pyroclastic materials. 3.5×106 8.3×106 m3 could still mobilized future coming decades.