Suitable geochemical markers to determine tsunami impact - an approach on coastal areas in Northern Japan

2021 ◽  
Author(s):  
Mike Frenken ◽  
Piero Bellanova ◽  
Yuichi Nishimura ◽  
Klaus Reicherter ◽  
Jan Schwarzbauer
Keyword(s):  
Coastal Areas ◽  
Tsunami Deposits ◽  
Destructive Effect ◽  
Linear Alkylbenzene ◽  
Polycyclic Aromatic ◽  
Geochemical Markers ◽  
Pollutant Distribution ◽  
Related Compounds ◽  
Terrestrial Material ◽  
Northern Japan

<p>The 2011 Tohoku-oki tsunami had a destructive effect and impact on the coast of Japan. Coinciding with the inundation of vast coastal areas, the catastrophic event released many pollutants from damaged facilities but also remobilized sediment-bound residues. These environmental and depositional variations left a distinct signature in the sediment, both sedimentologically and geochemically.</p><p>A wide variety of organic geochemical substances were detected in the sampled sediment profiles in Northern Japan (Misawa harbor, Futakawame and Oirase). Some compounds reflect the 2011 tsunami’s impact and may serve as possible indicators for further investigation of the inundation and backwash, sediment and pollutant distribution, and the preservation. For comparability, the tsunami samples and the respective over- and underlying layers (topsoil & soil) were analyzed.</p><p>The selected compound groups differentiated the tsunami layer from the non-affected layers. Natural compounds, relocated by the tsunami, revealed an enrichment of short-chained <em>n</em>-alkanes as expressed by the terrigenous/aquatic ratio (TAR) and locally accumulated <em>n</em>-aldehydes pointing to an intensive mixing of marine and terrestrial material. Petrogenic pollutants, for instance hopanes, steranes, and polycyclic aromatic hydrocarbons (PAHs), illustrate a higher load in tsunami sediments as the result of damage of harbor facilities. Sewage-related compounds, such as linear alkylbenzene (LABs) and diisopropylnaphthalene (DIPN), were also enriched in the tsunami samples in contrast to the surrounding sites. Another compound group enriched in the tsunami deposits, are chlorinated pollution burdens by the backwash, such as DDX and polychlorinated biphenyls (PCBs), remobilized by erosion dominantly.</p><p>The different environmental- and pollution-related compounds illustrate the suitability of geochemical markers as indicators to assess tsunami impact in 2011 Tohoku-oki tsunami affected sediments of Misawa harbor, Futakawame and Oirase in Northern Japan.</p>

Organic geochemical analysis of multiple tsunami deposits of the last century at the Aomori coast (Northern Japan)

2020 ◽  
Author(s):  
Mike Frenken ◽  
Piero Bellanova ◽  
Yuichi Nishimura ◽  
Jan Schwarzbauer ◽  
Klaus Reicherter
Keyword(s):  
Soil Layer ◽  
Strong Increase ◽  
Coastal Protection ◽  
Tsunami Deposit ◽  
Field Site ◽  
Tsunami Deposits ◽  
Anthropogenic Markers ◽  
Eyewitness Reports ◽  
Polycyclic Aromatic ◽  
Northern Japan

<p>Japan, more precisely, the eastern coastal areas of Honshu, are one of the most affected areas of tsunamis in the world. Major events within the last century were three Sanriki-oki tsunamis (1896, 1933, 1968), and the most recent 2011 Tohoku-oki tsunami, triggered by the 9.1 M<sub>W</sub> Tohoku-oki earthquake, which caused massive damage along the coastlines.</p><p>The 2011 Tohoku-oki tsunami overtopped the coastal defense walls with waves of 6-10 m height along the shores of the Aomori Prefecture in Northern Japan. The inundation reached up to 550 m inland, however, sandy tsunami deposits are limited to 250 – 350 m of the total inundation distance. At the field site of Misawa Harbor the well-preserved identifiable tsunami remains show up to 18 cm thick sand layers with sedimentary features, such as fining upward sequences, mud caps and rip-up clasts. The sandy deposits were enclosed in the soil of the coastal protection forest. Along with the sedimentary record of the tsunami, the use of organic geochemical indicators can provide a better understanding of the extend and processes, such as the deposition of tsunami layers and the backwash, of the inundation by the 2011 Tohoku-oki tsunami. The devastating damages caused by the interaction of tsunami and earthquake released pollutants associated as biological and anthropogenic markers. These released pollutants give the tsunami deposit an unique geochemical signature, that is distinguishable from the background sedimentation. Organic-geochemical results reveal a strong increase of anthropogenic (polycyclic aromatic hydrocarbons, pesticides and chlorinated compounds) and a variation of biological markers (i.e. n-alkanes, fatty acids) in the 2011 tsunami deposit close to the fishery port. During the analysis of the samples, another variation of biomarker and anthropogenic marker were identified right below the soil layer of the current forest. This layer is as well distinguishable from the paleo-dune that marks the lowest sedimentological unit at the field site. This differentiation shows the likely impact of a historical Sanriki-oki tsunami (1896, 1933 or 1968). These organic geochemical results in combination with local eyewitness reports of the tsunamis and lead to the assumption that the sedimentary archive of the Aomori coastline contains and preserved at two or more tsunami events of the last century.</p><p>The inclusion of organic geochemical markers to expand the characterizing and identifying proxies used in tsunami research are important to get a better understanding of the processes and deposition during tsunamis. Furthermore, this method can detect tsunami deposits beyond the visible recognizability of sedimentological identification of tsunami deposits and therefore can serve as a blue-print for historical and paleo-tsunami studies, as most of them only rely on visible sand deposits as marker for inundation distances from the beach. The high-resolution geochemical application can gain more information than standard techniques, like the identification of the “invisible” tsunami layer exceeding the limits of sandy deposits or the deposition in similar sedimentary textures, capturing a broader picture of the event.</p>

Assessment of the pyrogenic pollution of the soil-plant system on the base of geochemical markers for a local model of transport pressure

2021 ◽  
Vol 7 (1) ◽  
pp. 65-86
Author(s):  
A.P. Khaustov ◽  
◽  
M.M. Redina ◽  
Keyword(s):  
Heavy Traffic ◽  
Monitoring Program ◽  
Forest Park ◽  
Plant System ◽  
Local Pollution ◽  
Sources Of Pollution ◽  
Functional Zones ◽  
Integral Characteristics ◽  
Polycyclic Aromatic ◽  
Geochemical Markers

The choice of informative indicators for local estimates of the transport pressure on urban soil-plant systems is a serious problem of preserving green spaces. The spatial variations of the characteristics of the flows of marker compounds (polycyclic aromatic hydrocarbons (PAHs) acting as geochemical markers), the integral characteristics of the toxicity of soil pollutants, roots and aerial parts of plants TEQ, as well as the values of indicator ratios based on the concentrations of PAHs in the media are considered. The object of local research is the RUDN University campus (Moscow, Russia) with an adjacent forest park area. The territory is located in the zone of influence of heavy traffic flows and is experiencing an intense load from emissions. The state of the territory is monitored at 33 points according to a unique monitoring program. Pollution indicators showed different informativeness for constructing transport pressure models. Various modes of pollution in 3 functional zones of the territory are revealed; the zones of influence of the main sources of pollution are justified. The indicator ratios confirmed the leading source of pollution –pyrogenic emissions of transport, but they are to varying degrees sensitive to the activity of local pollution sources. Priority routes of PAH intake and accumulation in the components of the soil and plant system were identified. For the first time, a correlation between a number of ratios and indicators of polyarene contamination toxicity (TEQ) was established.

scholarly journals Exploring Offshore Sediment Evidence of the 1755 CE Tsunami (Faro, Portugal): Implications for the Study of Outer Shelf Tsunami Deposits

Minerals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 731 ◽  
Author(s):  
Vincent Kümmerer ◽  
Teresa Drago ◽  
Cristina Veiga-Pires ◽  
Pedro F. Silva ◽  
Vitor Magalhães ◽  
...  
Keyword(s):  
Grain Size ◽  
Magnetic Susceptibility ◽  
Multidisciplinary Approach ◽  
Outer Shelf ◽  
Tsunami Deposits ◽  
Sedimentary Records ◽  
Recurrence Intervals ◽  
Terrestrial Material ◽  
Water Depths ◽  
Tsunami Event

Outer shelf sedimentary records are promising for determining the recurrence intervals of tsunamis. However, compared to onshore deposits, offshore deposits are more difficult to access, and so far, studies of outer shelf tsunami deposits are scarce. Here, an example of studying these deposits is presented to infer implications for tsunami-related signatures in similar environments and potentially contribute to pre-historic tsunami event detections. A multidisciplinary approach was performed to detect the sedimentary imprints left by the 1755 CE tsunami in two cores, located in the southern Portuguese continental shelf at water depths of 58 and 91 m. Age models based on 14C and 210Pbxs allowed a probable correspondence with the 1755 CE tsunami event. A multi-proxy approach, including sand composition, grain-size, inorganic geochemistry, magnetic susceptibility, and microtextural features on quartz grain surfaces, yielded evidence for a tsunami depositional signature, although only a subtle terrestrial signal is present. A low contribution of terrestrial material to outer shelf tsunami deposits calls for methodologies that reveal sedimentary structures linked to tsunami event hydrodynamics. Finally, a change in general sedimentation after the tsunami event might have influenced the signature of the 1755 CE tsunami in the outer shelf environment.

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