Coastal Plain Of Israel Research Articles

Shedding light on the Ophel biome: the trans-Tethyan phylogeography of the sulfide shrimp Tethysbaena (Peracarida: Thermosbaenacea) in the Levant.

Tethysbaena are small peracarid crustaceans inhabiting extreme environments such as subterranean lakes and thermal springs, represented by endemic species found around the ancient Tethys, including the Mediterranean, Arabian Sea, Mid-East Atlantic, and the Caribbean Sea. Two Tethysbaena species are known from the Levant: T. relicta, found along the Dead Sea-Jordan Rift Valley, and T. ophelicola, found in the Ayyalon cave complex in the Israeli coastal plain, both belonging to the same species-group based on morphological cladistics. Along the biospeleological research of the Levantine subterranean fauna, three biogeographic hypotheses determining their origins were proposed: (1) Pliocenic transgression, (2) Mid-late Miocenic transgression, and (3) The Ophel Paradigm, according to which these are inhabitants of a chemosynthetic biome as old as the Cambrian. Tethysbaena specimens of the two Levantine species were collected from subterranean groundwaters. We used the mitochondrial cytochrome c oxidase subunit I (COI) gene and the nuclear ribosomal 28S (28S rRNA) gene to establish the phylogeny of the Levantine Tethysbaena species, and applied a molecular clock approach for inferring their divergence times. Contrary to the morphological cladistic-based classification, we found that T. relicta shares an ancestor with Tethysbaena species from Oman and the Dominican Republic, whereas the circum-Mediterranean species (including T. ophelicola) share another ancestor. The mean age of the node linking T. relicta from the Dead Sea-Jordan Rift Valley and Tethysbaena from Oman was 20.13 MYA. The mean estimate for the divergence of T. ophelicola from the Mediterranean Tethysbaena clade dated to 9.46 MYA. Our results indicate a two-stage colonization of Tethysbaena in the Levant: a late Oligocene transgression, through a marine gulf extending from the Arabian Sea, leading to the colonization of T. relicta in the Dead Sea-Jordan Rift Valley, whereas T.ophelicola, originating from the Mesogean ancestor, inhabited anchialine caves in the coastal plain of Israel during the Mid-Miocene.

The Oxford Handbook of Contemporary Middle Eastern and North African History

The Oxford Handbook of Contemporary Middle Eastern and North African History

Climate, sea level and culture in the Southeastern Mediterranean 20–4 ky BP

In this paper sediments accumulated between 20 and 4 ky BP on the Israeli coastal plain and their cultural contents are described. Sediments carried by the Nile River into the Mediterranean are transported northward along the Levant coast. These sediments are intermittently windblown on land and together with their derivative sandy loams form the bulk of sediments on the coastal plain of Israel. The younger these sediments are further west they are located. The sand beds apparently accumulated during cold and dry periods and pedogenesis occurred during warm and humid periods. Cultural remains on the coastal plain are encountered only in the soils. Hence in periods of sand transport humans avoided the coastal plain. Between the Last Glacial Maximum (LGM, ca. 18–20 ky BP) and about 4 ky BP, global sea level rose from −130 to 0m. The coastal sediments accumulated during that period are here correlated with both sea level and climatic factors. From the last glacial the living space was continuously shrinking under the encroaching sea and human communities were continuously driven landward. Cultural evolution since 20 ky ago includes major leaps such as the move from hunting-gathering nomads to permanent, year-round settlements, the birth of religion, domestication and food production. Climatic events seemingly played a minor role in these leaps. They were apparently initiated by social factors possibly stemming from environmental constraints – the progressive loss of living space.

Self‐organizing map classification of the boundary layer profile: A refinement of Eastern Mediterranean winter synoptic regimes

AbstractThe boundary layer (BL) profile over the coastal plain of Israel, Eastern Mediterranean (EM), varies considerably during winter. Although in the context of air pollution, the characteristics of the BL height (BLH) was intensively investigated, a quantitative classification of the BL profile regimes has not been performed. Here, we seek to reveal the dominant, recurring regimes of the BL profiles, their quantitative characteristics and links to regional synoptic‐scale patterns. An objective unsupervised classification of winter BL radiosonde profiles is performed for the first time by multi‐parameter self‐organizing map (SOM) analysis. The analysis uses high‐resolution, 12:00‐UTC data of wind, temperature, humidity and pressure measurements during December to February 2007–2018, and yields 30 distinct profile regimes. Composite analysis using ERA5 reanalysis suggests strong association between the profile regimes and synoptic weather systems and highlights four groups: (a) Deep winter cyclones with strong westerly wind and precipitation; (b) Strong surface anticyclones and Red Sea troughs (RST) with a mid‐tropospheric ridge, moderate dry easterly wind and extreme temperatures. (c) Moderate pressure gradients under shallow cyclones, anticyclone to the west and RST to the east of Israel. (d) Active RSTs, accompanied by upper‐tropospheric trough/cutoff low and heavy precipitation. For the first time, general objective classification observes the active RST without requiring specific criteria. Consistent with previous knowledge, the new classification exhibits distinct categories of thermal stability, BLH and turbulence. Importantly, we show that the automatic objective classification of profile data from a single station can be a sensitive discriminator of winter synoptic regimes in the EM, and therefore explains the variability of the BL profile. It facilitates the study of the interaction between the BL and the free troposphere and may improve the prediction of air pollution or future BL profile regimes based on long time series from historical data or climate models.

Life in the Dunes

ABSTRACT This article discusses a section of the Israeli coastal plain known as Yavneh Sands between 1800 and 1948. This sand-dune strip, which legally belonged to the large village of Yubna/Yavneh and to the waqf of the major pilgrimage site of Nabi Rubin, was a peripheral territory, both economically and socially. The area was de facto controlled by wandering and sedentary Bedouin groups, who were accompanied by (seasonal?) peasant villagers, fishermen, and—in late summertime—numerous pilgrims from various coastal towns and villages who made their way to and from Nabi Rubin. These people usually left behind quantitatively and qualitatively modest material traces, which reinforce the assumption that the various Late Ottoman and Mandatory sites documented in the Yavneh Sands area were not permanent settlements but rather seasonal farmsteads and mainly temporary and even one-time campsites.

Chalcolithic groundwater mining in the southern Levant: open, vertical shafts in the Late Chalcolithic central coastal plain settlement landscape of Israel

Levantine adaptive water subsistence and exploitative water management studies concerning late pre- and proto-history have intensified since 2000. This comes in the wake of findings concerning domestic water (e.g., groundwater wells and surface irrigation systems) in particular in the eastern Mediterranean basin. Excavations conducted over the last 15 years on Israel's central coastal plain revealed several clusters of anthropogenic, vertical, narrow, deep shafts, apparently disassociated from contemporary settlement or burial localities. The shafts were cut through local kurkar and/or hamra soils. Despite their seemingly isolated, open-space locations within the settlement landscape, the shaft fills yielded a rich, albeit secondary source of typical settlement waste, consisting mostly of discarded pottery vessels, chipped- and ground-stone tools, and faunal remains. All these remains date exclusively to within the Late Chalcolithic period (LC1), contemporary with and relatable to the Beer Sheva aspect of the period (c. 4200 cal BC-3900 cal BC). This paper reviews the current state of research vis à vis these shafts in the eastern Mediterranean basin, in an attempt to integrate the recently recorded phenomenon of Late Chalcolithic shaft clusters in Israel's central coastal plain, into the framework of artificial groundwater wells from the early Pre-Pottery Neolithic through the Late Chalcolithic periods.

Multispectral Approach for Identifying Invasive Plant Species Based on Flowering Phenology Characteristics

Invasive plant species (IPS) are the second biggest threat to biodiversity after habitat loss. Since the spatial extent of IPS is essential for managing the invaded ecosystem, the current study aims at identifying and mapping the aggressive IPS of Acacia salicina and Acacia saligna, to understand better the key factors influencing their distribution in the coastal plain of Israel. This goal was achieved by integrating airborne-derived hyperspectral imaging and multispectral earth observation for creating species distribution maps. Hyperspectral data, in conjunction with high spatial resolution species distribution maps, were used to train the multispectral images at the species level. We incorporated a series of statistical models to classify the IPS location and to recognize their distribution and density. We took advantage of the phenological flowering stages of Acacia trees, as obtained by the multispectral images, for the support vector machine classification procedure. The classification yielded an overall Kappa coefficient accuracy of 0.89. We studied the effect of various environmental and human factors on IPS density by using a random forest machine learning model, to understand the mechanisms underlying successful invasions, and to assess where IPS have a higher likelihood of occurring. This algorithm revealed that the high density of Acacia most closely related to elevation, temperature pattern, and distances from rivers, settlements, and roads. Our results demonstrate how the integration of remote-sensing data with different data sources can assist in determining IPS proliferation and provide detailed geographic information for conservation and management efforts to prevent their future spread.

Hybridisation and detection of a hybrid zone between mesic and desert ragworts (Senecio) across an aridity gradient in the eastern Mediterranean

ABSTRACTBackground: Hybrid zones provide excellent opportunities for studying plant adaptation and speciation.Aims: We tested whether two herbaceous species of Senecio, S. vernalis and S. glaucus, hybridise in the eastern Mediterranean region and form a hybrid zone across an aridity gradient in the Jordan Rift Valley.Methods: Allozyme variation surveyed across both species was analysed by the programme STRUCTURE to assign individuals to genetic groups and determine levels of admixture. Populations in the Jordan Rift Valley were subsequently subjected to a cline analysis.Results: STRUCTURE showed that interspecific hybrids were produced at low frequency along the Israeli coastal plain where S. glaucus is represented by ssp. glaucus. In contrast, hybrids were more commonly produced in central populations of the Jordan Rift Valley. Here, the two species form a hybrid zone with S. vernalis occurring in mesic sites to the north and S. glaucus (ssp. coronopifolius) in arid sites to the south. Cline analysis showed that the hybrid zone is centred towards the northern end of the Dead Sea, but the analysis failed to distinguish how it is maintained.Conclusions: Future detailed genetic and ecological analysis of the Senecio hybrid zone should improve our understanding of plant adaptation and speciation across aridity gradients.

Natural saturation of OSL and TT-OSL signals of quartz grains from Nilotic origin

Abstract The upper limit of optically stimulated luminescence (OSL) dating technique is usually defined by signal saturation. In nature the OSL signal saturates even faster than in the laboratory. Here we present a study on natural saturation of OSL and thermally transferred OSL (TT-OSL) signals of quartz grains from Nilotic origin. Quartz samples from two representative sections from the coastal plain of Israel, and which span approximately similar time frames, were used to construct semi-natural dose response curves (DRC) for OSL and TT-OSL by plotting the natural signal of samples against their depth and equivalent dose (De). Samples from these two sections, as well as from other sites, define typical OSL and TT-OSL DRC's for Nilotic quartz that was transported to the eastern shores of the Mediterranean Sea. The constructed semi-natural OSL DRC is unique to the quartz of Nilotic origin and indicates the upper limit for reliable OSL dating of this quartz at 140 Gy due to signal saturation. The natural TT-OSL luminescence grows linearly up to 400 Gy, and is constant for 400–600 Gy. Steady-state between TT-OSL trap-filling, due to ionizing radiation, and concurrent thermal emptying of these traps is achieved at 600 Gy. TT-OSL dating of the Nilotic quartz is expected to underestimate ages over ∼120 ka due to the low thermal stability of the signal.

A new modeling approach for assessing the contribution of industrial and traffic emissions to ambient [formula omitted] concentrations

The Optimized Dispersion Model (ODM) is uniquely capable of incorporating emission estimates, ambient air quality monitoring data and meteorology to provide reliable high-resolution (in both time and space) air quality estimates using non-linear regression. However, it was so far not capable of describing the effects of emissions from elevated sources. We formulated an additional term to extend the ODM such that these sources can be accounted for, and implemented it in modeling the fine spatiotemporal patterns of ambient NOx concentrations over the coastal plain of Israel. The diurnal and seasonal variation in the contribution of industry to the ambient NOx is presented, as well as its spatial features. Although industrial stacks are responsible for 88% of the NOx emissions in the study area, their contribution to ambient NOx levels is generally about 2% with a maximal upper bound of 27%. Meteorology has a major role in this source allocation, with the highest impact of industry in the summer months, when the wind is blowing inland past the coastal stacks and vertical mixing is substantial. The new Optimized Dispersion Model (ODM) out-performs both Inverse-Distance-Weighing (IDW) interpolation and a previous ODM version in predicting ambient NOx concentrations. The performance of the new model is thoroughly assessed.

3D Effects of Sedimentary Wedges and Subsurface Canyons: Ground‐Motion Amplification in the Israeli Coastal Plain

Abstract We study the propagation of seismic waves, the resulting ground motions, and their amplification atop sedimentary structures underlying continental passive margins. We employ a set of generic models with increasing complexity within a framework of a 3D numerical scheme. The basic geological structure and velocity model were derived from the subsurface of the Israeli coastal plain where soft sediments form a wedge over the stiffer bedrock and fill subsurface canyons that incise deep into the bedrock. Ground motions were modeled for both seaside and landside seismic sources. We show that for a landside source, peak ground velocities (PGVs) atop a sedimentary wedge are amplified by a maximum factor of 2.6 and on average by a factor of 1.6, relative to a reference model. This amplification is mainly due to the ellipticity of Rayleigh waves in the soft sediment layer. Spatial distribution of amplification factors shows that sedimentary wedges do not exhibit a prominent edge effect. Atop sediment‐filled canyons and landside source, PGV are amplified by a maximum factor of 3.3, relative to a reference model, along the exposed part of the canyon. The PGV amplification factor in the canyon relative to adjacent hard‐rock site is up to 2.4. PGV amplification atop the sediment‐filled canyons is mainly due to the geometrical focusing of SH waves. Based on our findings, we present a simplified ground‐motion amplification map for the Israeli coastal plain. Electronic Supplement: Animations of the three components of the ground‐motion models.

A Roman pottery kiln at Khirbet ‘Azzun (Ra‘anana), Israel

This paper focuses on a 3rd–4th century AD pottery kiln from Khirbet ‘Azzun (Ra‘anana), in the Sharon, in the central coastal plain of Israel. The kiln belongs to the updraft type, with an oval-shaped and crater-like firebox, a fuel opening on the north and spanned by brick arches designed to support the floor of the missing ware chamber. Like many other kilns in that region, it produced storage jars. Our kiln is the first from the region dating to the Roman period, to be fully studied. The kiln’s components, technology and supposed process of operation will be examined closely, in light of other kilns from Roman-Byzantine Palestine and ethnoarchaeological evidence.

Urbanization effects on sediment and trace metals distribution in an urban winter pond (Netanya, Israel)

This paper aims to elucidate urban development-induced processes affecting the sediment and the distribution of contaminating metals in a seasonal pond located in the highly populated Israeli Coastal Plain. The paper demonstrates how an integrated approach, including geochemical, sedimentological, geochronological, mathematical, historical, and geographical analyses, may decipher a complicated and dynamic metal pollution history in a sedimentary environment controlled by anthropogenic activity. Three short sediment cores were collected from the margins and center of a small urban pond (Dora, Netanya), located within the Israeli Coastal Plain. Profiles of grain size, organic matter (OM), trace metals (Pb, Zn, V, Ni, Cu, Cr and Co), Pb isotopic ratios, and 210Pb activities (center and southern cores) were determined and a geochemical mixing model was employed (southern core). The watershed contour was calculated, and aerial photos and satellite images were examined. Construction activities in the watershed were chronologically associated with coarse sediment transport and deposition in the margins of the pond. The upper sandy layers were superimposed on layers rich in fine particles and OM, high concentrations of trace metals, and with Pb isotopic composition of more recent petrol. In the 210Pb-dated southern core, deep metal-rich layers with petrol-related Pb isotopic ratios were inconsistent with metal emissions history. These findings point to mobility and migration of recent contamination metals through the coarse upper sediment layers and into deeper denser layers, confirmed also by a geochemical mixing model. Conversely, in the center of the pond, homogeneous fine particles were deposited with metal profiles consistent with regional emissions. A small urban pond was found to provide an important case study for understanding heavy metal pollution records in highly populated regions. The margins of the pond depicted the surrounding urban development and the induced coarse sediment erosion, accompanied with post-depositional metal mobility. Due to the proximate developing residential areas, high metal concentrations accumulated in the margins, overshadowing regional atmospheric pollution levels recorded by sediment at the center of the pond.

New perspectives on coastal landscape reconstruction during the Late Quaternary: A test case from central Israel

The stratigraphic architecture of coastal plains is determined by the interactions between local (e.g. fluvial processes and topography), regional (e.g. climate) and global (e.g. sea level) forcing factors, primarily during the Late Quaternary Period. Detailed stratigraphic and sedimentological analyses of boreholes, cored between coastal ridges in the lowlands, coupled with optically stimulated luminescence (OSL) dating, and integrated with existing onshore and offshore databases, has enabled a 4-D reconstruction of the evolution of the coast of Israel during the last glacial-interglacial cycle. This model revealed that Nilotic-sourced littoral sand, intermittently transported inland by wind, has either been lithified into aeolianite or pedogenized into orange–brown palaeosol from about 100ka to 8ka. Dark silty clay wetlands were deposited between the aeolian coastal ridges adjacent to streams which cut the Israeli coastal plain and flow westward, from the Last Glacial Maximum until the onset of the Holocene. These units are topped by beach and aeolian quartz sand dated to 6.6–0.1ka. Diachronous thicknesses and lithological dissimilarities were identified between the sections studied and previous reports on adjacent coastal aeolianite ridges. Streams were found to be a dominant control on the stratigraphical composition and related facies architecture due to fluvial-induced erosion. Consequently, the relief variations between the lowland and cliff controlled aeolian pedogenesis as well as alluvial processes from about 80 to 5ka. Climate, mainly influenced by precipitation and dust input, induced pedogenic processes; while sea level lowstand during the Last Glacial Maximum is shown to have hindered sediment deposition in the shallow offshore, which in turn affected aeolian transport, reducing sediment accumulation on the palaeo-coastal plain. The palaeoenvironmental model presented in the current study serves as an example for understanding the evolution of similar low-latitude siliciclastic-rich low-gradient shelf-coastal areas during the last glacial-interglacial cycle. Furthermore, it demonstrates the influence of local to global forcing factors on these environments.

Earthquake damage history in Israel and its close surrounding - evaluation of spatial and temporal patterns

Israel was hit by destructive earthquakes many times in the course of history. To properly understand the hazard and support effective preparedness towards future earthquakes, we examined the spatial and temporal distribution of the resulted damage. We described in detail our systematic approach to searching the available literature, collecting the data and screening the authenticity of that information. We used GIS (Geographic Information System) to map and evaluate the distribution of the damage and to search for recurring patterns. Overall, it is found that 186 localities were hit, 54 of them at least twice. We also found that Israel was affected by 4, 17, 8 and 2 damaging earthquakes that originated, respectively, from the southern, central, central-northern and northern parts of the Dead Sea Transform (DST). The temporal appearance of the northern earthquakes is clustered; the central earthquakes are more regular in time, whereas no damage from the north-central and the central quakes, with the exception of the year 363 earthquake, seems to have occurred south of the Dead Sea region.Analyzing the distribution of the damage, we realized that the number of the damage reports reflects only half of the incidents that actually happened, attesting to incompleteness of the historical catalogue. Jerusalem is the most reported city with 14 entries, followed by Akko (Acre), Tiberias, Nablus and Tyre with 8, 7, 7 and 6 reports, respectively. In general, localities in the Galilee and north of it suffered more severely than localities in central Israel with the exception of Nablus and the localities along the coastal plain of Israel, most probably due to local site effects. For the sake of hazard management, these observations should be considered for future planning and risk mitigation.

The age of the Lower Paleolithic site of Kefar Menachem West, Israel—Another facet of Acheulian variability

A salvage excavation at the Lower Paleolithic site of Kefar Menahem West in the interior of the Israeli coastal plain yielded a flake industry devoid of handaxes and their byproducts. The archeological finds covering an area exceeding 2000m2, are found at the contact of two distinct sedimentological units: Quartzic Brown and hamra (red clay loam paleosols). The absence of handaxes hamper placing the site within the relative chronology of the Lower Paleolithic record of the Levant.New paleomagnetic analysis coupled with optically stimulated luminescence (OSL) and thermally transferred optically (TT-OSL) dating yielded a chronological range between 780 and 460ka for the archeological occupation. The techno-typological similarities with Late Acheulian assemblages together with possible variations in the mode of occupations by early hominids at the site, both suggest that the KMW should be conceived as part of the Late Acheulian variability.

Technological radiation and the process of technological change at the end of the Levantine Lower Paleolithic

The systematics of Paleolithic stone tools often borrows the concept of lineage from biological evolution. The goal of this paper is to explore the applicability of the concept of adaptive radiation that plays a critical role in evolutionary biology for the study of Paleolithic technology. It is proposed that the concept of technological radiation might be a useful addition to the emphasis on lineages found in the work of Simondon, Leroi-Gourhan, and Boëda. The idea of a technological radiation is then applied to the later stages of the Lower Paleolithic of the southern Levant, particularly the coastal plain of Israel, and the transition to the Middle Paleolithic.

Taxonomy and Biology ofAndricus miriami(Hymenoptera: Cynipidae: Cynipini)—A Remarkable Bud-Galling Cynipid from the Middle East

The rich Israeli fauna of cynipid gall wasps (Hymenoptera: Cynipidae) includes dozens of species, many of which induce complex, conspicuous galls on the five local oak species, in what constitutes the southern edge of distribution for both the wasps and their host plants. The taxonomy and life history of the cynipid species of the Levant in general, and of Israel in particular, are virtually unstudied, although some of the Israeli galls were recorded and keyed in the 1960s. As part of a comprehensive revision of the Israeli cynipid fauna, we describe here Andricus miriami n. sp., which induces one of the most conspicuous and complex galls in inflorescence buds of Quercus ithaburensis along the Galilee and Coastal Plain in Israel, and in north-western Jordan. The species has been treated in the literature as a nomen nudum since 1968, and its current description clarifies its taxonomic status and validates the name given to it when first reported. We provide a detailed description of adults of the asexual generation and the galls they induce, as well as information on their life history and distribution.

Molluscan live and dead assemblages in an anthropogenically stressed shallow-shelf: Levantine margin of Israel

Abstract Mismatches between live and dead molluscan assemblages associated with recent, rapid, anthropogenic changes, can be used to track these changes. The eastern Mediterranean is naturally oligotrophic, but recent urbanization of the Israeli coastal plain has enriched the littoral environment by injection of large amounts of treated wastewater onto the shelf. The largest point source is the Dan region wastewater project (Shafdan). Taxonomy and species rank order of abundance of modern (sediment-top) death assemblages were compared to live-collected mollusk assemblages, from two clean control stations (PL29, PL64) and a polluted site (PL3), near the Shafdan sewage sludge outlet at 36 m water depth. Seasonal variability was captured by dredge and box-core sampling in winter (January), spring (May), summer (July) and fall (November) of 2012. Over 11,000 individuals of bivalves and gastropods were collected and analyzed. Diversity indices and nMDS and cluster analysis showed significant differences between live and dead assemblages from all stations and seasons. However, the rank order of the abundant live and dead species remained similar at each sampling station, resulting in high live–dead agreement of Jaccard-Chao index and Spearman's rho similarity coefficient. Live–dead agreement of molluscan assemblages was preserved in the Shafdan area by the naturally high abundance of species that are tolerant to pollution, and by the annual dispersion of the sludge by winter storms, which prevent development of long-term anoxia. Moreover, the high frequency of storms in the winter of 2012 prevented a substantial amount of sludge from accumulating on the seafloor, explaining the similarity between the live assemblages of the polluted and the control sampling sites. Live–dead agreement is a test that is too conservative to track the impact of the Shafdan sludge on the macrobenthic fauna in the Israeli shelf. Other tests, especially the increase in the abundance of deposit-feeding pollution-tolerant species in the live assemblage, show that there is an ongoing impact of the sludge on the benthic community.

Historical sand injections on the Mediterranean shore of Israel: evidence for liquefaction hazard

The abundant silt and sand along the coastal plain of Israel have long been considered susceptible to liquefaction, but previous searches have failed to find field evidence for it. We report the first finding of typical liquefaction features and silty sand injections in trenches that were excavated behind a fourth century Byzantine dam on the Taninim Creek, some 850 m inland of the Mediterranean shore. The trenches revealed a series of flame-shape injections of silty sand that penetrate the overlying clay-rich soil. The injections are largest and most frequent within several meters of the point where the dam is badly damaged on the seaward side, which we interpret as a possible result of a large wave. Three features make the sand injections special: (1) their lower extent is commonly asymmetric with dominant southeastward vergence, away from the breach in the dam, (2) zigzag shapes characterize the upper parts of many injections, and (3) the size and frequency of the injections diminish gradually with distance from the dam until they completely disappear some 100 m away from it. We suggest that the sand injections can be explained by overpressure that was induced either directly by earthquake shaking or by a tsunami wave that breached the dam, filled the reservoir behind the dam and increased the pressure on the water-saturated silt and sand layers and triggered liquefied sand injections. The movement of water sloshing back and forth in the lake accounts for the zigzag shape of the injections. The similarity to structures that were observed in Thailand after the great 2004 tsunami and other palaeotsunami observations lead us to prefer the tsunami origin of the liquefaction features. Based on the stratigraphic position, the archeological context, and the historical accounts, we suggest that an earthquake of November 25, 1759 is the most plausible trigger of the sand injections, either directly or via earthquake-induced tsunami. The observations demonstrate the vulnerability of the densely populated coastal plain to liquefaction.