Although the Gulf of Aqaba-Eilat is located in the tectonically active northern Red Sea, it has been described as low-risk with regard to tsunami activity because there are no modern records of damaging tsunami events and only one tsunami (1068 AD) referred to in historical records. However, this assessment may be poorly informed given that the area was formed by and is located along the seismically active Dead Sea Fault, its population is known to fluctuate in size and literacy in part due to its harsh hyper-arid climate, and there is a dearth of field studies addressing the presence or absence of tsunamigenic deposits. Here we show evidence from two offshore cores for a major paleotsunami that occurred ~2300 years ago with a sedimentological footprint that far exceeds the scarce markers of the historically mentioned 1068 AD event. The interpretation is based on the presence of a laterally continuous and synchronous, anomalous sedimentological deposit that includes allochtonous inclusions and unique structural characteristics. Based on sedimentological parameters, these deposits could not be accounted for by other transport events, or other known background sedimentological processes.

Amino acids compound-specific nitrogen stable isotope analysis (AA-CSIA) is an emerging tool in ecology for understanding trophic system dynamics. While it has been successfully used for several independent studies across a range of environments and study locations, researchers have encountered calculation issues for determining trophic position values. Most studies introduce modifications to the constants of trophic position equation calculations, but then fail to account for the equation variations when comparing across separate research studies. The broad acceptance of this approach is anchored in an underlying presumption that no addition of the exogenous nitrogen atom occurs in the different methods; and therefore, such variations should not affect the outcome. In this paper, we evaluate the use of the EZfaast amino acid derivatization kit (chloroformate) and compare it to the isotopic results of two other derivatization methods. We highlight new considerations for working with AA-CSIA that might account for some of the variations in the results and lead researchers to modify constants in the equation. This study concludes that developing unique constants per derivatization method is required to have more accurate cross-study comparisons of trophic positions.

<p>The first physical field evidence for any dated tsunami event on the coast of Israel was discovered twenty years ago.  Since then, three campaigns of offshore core collections were completed with the aim of testing the validity of that interpretation, further completing the catalogue of known tsunami events, providing constraining data for models, determining associations with potential source tsunami-generating mechanisms, and assessing risk for purposes of emergency planning and coastal management.  Those follow-up coring campaigns provided many additional examples of anomalous sedimentary deposits that agreed with tsunami-derived interpretations and failed to fit criteria of other potential causes (e.g. floods, storms); reinforcing the theory that multiple tsunami events impacted that coastline and building a more complete record.  The interpretation of these offshore deposits has been improved by ongoing contributions from modern sedimentological studies following the set of recent megatsunamis.  Specifically, tsunami sediment characterization from modern tsunami studies has greatly improved the ability to recognize cryptic, anomalous deposits with higher confidence.  In addition, a small set of new land-based evidence has been identified, some of which match written historical records, and many that corroborate the offshore sedimentary record. In this presentation, a summary of these finds and the latest, most updated catalogue of events based on physical sedimentary deposits will be presented highlighting knowledge gained regarding variations in the efficacy of various proxies in the tsunami ‘tool box’ with relationship with this particular stretch of coastline.</p>

Introduction General ContextCoastal boulders are important because they document extreme wave actions, such as those that occur during storms and tsunamis. Furthermore, boulders are a unique type of deposit as they can consist of only few "particles." Nott (2003) demonstrated that information about the pre-transport setting of boulders is important. A variety of different approaches have been developed to consider boulder motion, assuming different pre-transport settings and simplifying assumption about the hydrodynamic forcing to quantify the storm or tsunami that moved boulders. We refer to Cox et al. (2020) for more information about Nott's 2003 approach, the most common approach from which others, such as Benner et al. (2010), Nandasena et al. (2011b), Nandasena et al. (2011a, Buckley et al. (2012), andBarbano et al. (2010), are derived. More fundamentally, if information about the causative events is available, and better yet, data that can be used to calibrate hydrodynamic models, boulder transport can be understood at a much more advanced level (see for example, Watanabe et al., 2019, and references therein). However, very often, especially for historic events or events in the geologic record, such information is not available-including the pre-transport setting of the boulder. None of the existing approaches can accommodate the ambiguity related to the causative process and pre-transport setting in a consistent manner. To address this shortcoming, we present a Monte-Carlo-type ensemble model with the capability to sample parameter distributions that describe the uncertainties around the pre-transport setting as well as how the flow interacts with the boulder.Boulders as heavy as 50 or 80 tonnes have been reported as moved by storms (Cox et al., 2012) and tsunamis (Dewey & Ryan, 2017). Just the fact that hydrodynamic forces during storms and tsunamis are capable of transporting such large particles is in itself astonishing and should narrate a cautionary tale independent of the causative process. However, much of the debate, when it comes to boulder deposits during coastal hazard events, is focused on whether the boulders were moved during a tsunami or a storm. Of course, it is important to delineate the causative boulder movement processes for hazard assessment, as while both storms and tsunamis can have devastating effects, they do vary in their coastal inundation, duration, and the character of how they impact the coastline. However, especially without enhanced knowledge and specific information about the hydrodynamic forcing, it remains difficult to defend a conclusion regarding whether a storm or a tsunami caused the motion of a boulder. Advanced numerical simulations, such as presented in Zainali and Weiss (2015), Kennedy et al. (2016) and Watanabe et al. (2019) are capable, but the wealth of information needed to create the input waves has only been recorded by tide gauges, wave buoys, or other measuring devices in the past few decades. Without these existing constraints, advanced simulations produc...