Lynchets are topographic ledges that are formed by the accumulation of colluvium behind a hedge grown perpendicular to the slope of a hillside. This colluvium constitutes a natural archive for the analysis of agricultural erosion over time, as we demonstrate in this study of a toposequence characterized by two lynchets along a loess slope. The detailed description of the soil catena coupled with OSL dating records the major erosional phases. The earliest phase begins during the late Neolithic at ca. 5,760 ± 500 yr. The upslope hedge is installed at ca. 2,710 ± 200 yr, at the very end of the Bronze Age or the beginning of the Early Iron Age and the downslope hedge is planted during the Early Middle Ages. Therefore, onwards from 2,710 ± 200 yr, erosion only affects individual plots or sections rather than the entire slope. Our dates also show that the soils on the uppermost portion of the slope had undergone a complete ablation prior to 2,710 ± 200 yr. This early erosional phase, likely Neolithic in age, is consistent with other dates obtained in the northern Alsace region.

Indonesia is exposed to earthquakes, volcanic activities, and associated tsunamis. This is particularly the case for Lombok and Sumbawa Islands in West Nusa Tenggara, where evidence of tsunamis is frequently observed in its coastal sedimentary record. If the 1815 CE Tambora eruption on Sumbawa Island generated a tsunami with well-identified traces on the surrounding islands, little is known about the consequences of the 1257 CE tremendous eruption of Samalas on the neighboring islands, and especially about the possible tsunamis generated in reason of a paucity of research on coastal sedimentary records in this area. However, on Lombok Island, the eruption of the Samalas volcano produced significant volumes of pyroclastic flows that entered the sea in the North and East of the island. These phenomena must have produced a tsunami that left their traces, especially on Sumbawa Island, whose western coastline is only 14 km away from Lombok’s eastern shore. Therefore, the main goal of this study is to investigate, find evidence, and determine the age of marine-origin sediments along the shore of the Alas Strait, Indonesia. We collected and analyzed samples of coral and seashells from marine deposits identified along the west coast of Sumbawa, i.e., in Belang Island and abandoned fishponds in Kiantar Village, in order to identify the sources and the occurrence period of these deposits events. Based on the radiocarbon dating of coral and seashell samples, we concluded that none of the identified marine deposits along the western coast of Sumbawa could be related chronologically to the 1257 CE eruption of Samalas. However, possible tsunami deposits located in Belang Island and abandoned fishponds in Kiantar Village yielded 4th century CE, 9th century CE, and 17th century CE. We also conclude that past large earthquakes triggered these tsunamis since no known volcanic eruption occurred near the Alas Strait at that time that may have triggered a tsunami.

L’UMR 7044 (ARCHIMEDE) regroupe une forte concentration d’archéologues, de philologues et d’historiens des mondes anciens dont la spécialité porte sur l’Europe moyenne et centrale, ainsi que sur la Méditerranée et ses voisins orientaux (Rome, Grèce, Byzance, Anatolie, Mésopotamie, Syro-Palestine, Égypte).

Today, coastal cities worldwide are facing major changes resulting from climate change and anthropogenic forcing, which requires adaptation and mitigation strategies to be established. In this context, sedimentological archives in many Mediterranean cities record a multi-millennial history of environmental dynamics and human adaptation, revealing a long-lasting resilience. Founded by the Phoenicians around 3000 years ago, Cádiz (south-western Spain) is a key example of a coastal resilient city. This urban centre is considered to be one of the first cities of western Europe and has experienced major natural hazards during its long history, such as coastal erosion, storms, and also tsunamis (like the one in 1755 CE following the destructive Lisbon earthquake). In the framework of an international, joint archaeological and geoarchaeological project, three cores have been drilled in a marine palaeochannel that ran through the ancient city of Cádiz. These cores reveal a ≥50 m thick Holocene sedimentary sequence. Importantly, most of the deposits date from the 1st millennium BCE to the 1st millennium CE. This exceptional sedimentary archive will allow our scientific team to achieve its research goals, which are (1) to reconstruct the palaeogeographical evolution of this specific coastal area; (2) to trace the intensity of activities of the city of Cádiz based on archaeological data, as well as geochemical and palaeoecological indicators; and (3) to identify and date high-energy event deposits such as storms and tsunamis.