Invisible tsunami deposits – the Misawa example, Japan

2021 ◽  
Author(s):  
Piero Bellanova ◽  
Mike Frenken ◽  
Yuchi Nishimura ◽  
Jan Schwarzbauer ◽  
Klaus Reicherter
Keyword(s):  
Analytical Data ◽  
Field Work ◽  
Organic Layer ◽  
Natural Environments ◽  
Sandy Sediment ◽  
Tsunami Deposit ◽  
Critical Observation ◽  
Sandy Deposit ◽  
Sand Sheets ◽  
Northern Japan

<p>With at least three reported waves, the 2011 Tohoku-oki tsunami’s destructive force caused massive damage along the Aomori coastline in northern Japan. At Misawa the coastal area was inundated up to 550 m inland and sandy sediment remnants can be traced to c. 350 m (c. 61-63% of the maximum inundation) from the shoreline.</p><p>The discovery of a floatable plastic object within a previously inconspicuous woody and organic layer in connection to our analytical data lead to the detection of a yet undocumented ‘invisible’ tsunami deposit. This layer is first appearing on top of the sandy deposit but then reaching even further inland (approx. 69-72% of the max. inundation). Initially the organic and woody layer was not evident during early stages of the field work and this would have been unchanged without the discovery of the floatable plastic particle embedded within the deposit. That critical observation was the turning point for the interpretation of the layer’s origin and thus our understanding of processes during the Tohoku-oki tsunami at the Aomori coast near Misawa harbor. Overall, may the first recognition of this woody-organic and up to now ‘invisible’ layer lead to an improvement in the understanding of tsunami processes and their sedimentological characteristics. Further, may the knowledge obtained from these types of deposits be transferred to and improve paleo-tsunami investigations, especially in rural natural environments, as sand sheets of historic and paleo-tsunamis represent minimum estimates for the coastal inundation and potential underestimations may be reduced by addressing the ‘invisible’ fraction of a tsunami’s inundation.</p>

scholarly journals Tracing woody-organic tsunami deposits of the 2011 Tohoku-oki event in Misawa (Japan)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Piero Bellanova ◽  
Mike Frenken ◽  
Yuichi Nishimura ◽  
Jan Schwarzbauer ◽  
Klaus Reicherter
Keyword(s):  
Analytical Data ◽  
Control Area ◽  
Organic Layer ◽  
Sandy Sediment ◽  
Tsunami Deposit ◽  
Organic Fraction ◽  
Tsunami Deposits ◽  
Tsunami Inundation ◽  
Sandy Deposit ◽  
Sand Sheets

AbstractWith a minimum of three reported waves, the 2011 Tohoku-oki tsunami’s destructive force caused massive damage along the northern Japanese Aomori coast. At Misawa the coastal control area was inundated up to 550 m inland and sandy sediment remnants can be traced to c. 350 m (c. 61–63% of the maximum inundation) from the shoreline. Linking the discovery of floatable plastic objects within a woody and organic layer to our analytical data lead to the detection of a yet undocumented woody-organic tsunami deposit first appearing on top of the sandy deposit but then reaching even further inland (approx. 69–72% of the max. inundation). By this observation our understanding of the documented part of the tsunami inundation may be improved. As a consequence, sand sheets of historic and paleo-tsunamis represent minimum estimates for the coastal inundation and underestimation may be reduced by addressing the woody and organic fraction of a tsunami’s inundation.

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>

scholarly journals Naturally Occurring Asbestos (NOA) in Granitoid Rocks, A Case Study from Sardinia (Italy)

Minerals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 442 ◽  
Author(s):  
Federico Lucci ◽  
Giancarlo Della Ventura ◽  
Alessandra Conte ◽  
Manuela Nazzari ◽  
Piergiorgio Scarlato
Keyword(s):  
Power Plants ◽  
Field Work ◽  
Natural Environments ◽  
Hydroelectric Power ◽  
Magmatic Complex ◽  
Naturally Occurring ◽  
Naturally Occurring Asbestos ◽  
Granitoid Rocks ◽  
Felsic Rocks

All six minerals defined as “asbestos” by the existing regulation on asbestos hazard, i.e., actinolite, tremolite, anthophyllite, crocidolite and amosite amphiboles, and the serpentine-group mineral chrysotile are typical constituents of mafic and ultramafic magmatic rocks of ophiolitic sequences. However, little is known about the presence and distribution of naturally occurring asbestos (NOA) in plutonic felsic rocks. The Isadalu magmatic complex outcropping in central Sardinia and belonging to the post-variscan Permian volcanic cycle, is described here as an interesting occurrence of fibrous amphiboles in granitoid rocks. Field work and collected mineralogical/petrological data show that NOA fibers from the Isadalu complex belong compositionally to the actinolite-tremolite series. They were generated by metasomatic growth on pristine magmatic hornblende, at ca. 470 °C at 1 kbar, during sodic-calcic hydrothermal alteration. In terms of environmental hazard, the Isadalu complex represents a high-value case study, since the actinolite-bearing felsic rocks outcrop in a strongly anthropized area. Here, towns with local and regional strategic infrastructures (dams, pipes, hydroelectric power plants, water supply, roads) have been developed since the last century, also using the granitoid asbestos-rich stones. The aim of this study is to demonstrate that NOA and relative hazard are not univocally connected to a restricted typology of rocks. This result should be taken into account in any future work, procedure or regulation defining asbestos occurrences in natural environments.

Biosocial aspects of Ainu hirsuteness

1969 ◽  
Vol 1 (2) ◽  
pp. 109-124 ◽  
Author(s):  
R. G. Harvey ◽  
D. R. Brothwell
Keyword(s):  
Field Work ◽  
Social Attitudes ◽  
Human Populations ◽  
Body Hair ◽  
Facial Hair ◽  
Controversial Subject ◽  
The Past ◽  
History Of ◽  
Methodological Problems ◽  
Northern Japan

SummaryThere are as yet few studies of body hair variation in man. Of all human populations, the Ainu of Japan are most famous for their alleged hirsuteness, and the history of this somewhat controversial subject is reviewed. Data are presented on chest, back and facial hair pattern and quantity in a sample of Ainu and Ainu/Japanese hybrids, resulting initially from field work by the Cambridge Expedition to Northern Japan in 1964. Methodological problems are discussed. Social attitudes to hairiness in Japan over the past few centuries are commented on, in view of their possible relevance in maintaining the biological distinctiveness of the Ainu. It is concluded that although the Ainu have more body hair than other Japanese, compared with some other groups—for instance American ‘Whites’—they can not be considered exceptionally hirsute.

scholarly journals A 17th-century Tsunami Deposit Discovered on the Eastern Iburi Coast, Hokkaido, Northern Japan

2007 ◽  
Vol 46 (2) ◽  
pp. 119-130 ◽  
Author(s):  
Yasuhiro Takashimizu ◽  
Tsumoru Sagayama ◽  
Kenji Nishina ◽  
Takao Oka ◽  
Yugo Nakamura ◽  
...  
Keyword(s):  
17Th Century ◽  
Tsunami Deposit ◽  
Northern Japan

Semi-automated assessment of geological phenomena of Active Deformation Areas (ADA) detected by radar interferometry in Alt Urgell and Cerdanya, Catalonia (Spain)

2021 ◽  
Author(s):  
Ivan Fabregat ◽  
Jaume Casanovas ◽  
Jordi Marturià ◽  
Pere Buxó ◽  
Anna Barra
Keyword(s):  
Regional Scale ◽  
Field Work ◽  
Risk Identification ◽  
Current Data ◽  
Natural Environments ◽  
Active Deformation ◽  
Ground Movements ◽  
Radar Satellite ◽  
Geological Phenomenon

<p>Geological hazards related to ground movements are difficult to assess at a regional scale due the lack of detailed information on the occurrence of the phenomena and the large number of potential vulnerable elements in the territory. Therefore, progress in analyzes at the regional scale can be a very useful tool for risk management.</p><p>This work, developed in the Alt Urgell and La Cerdanya counties (Catalunya, NE Spain) has served as the basis for the geological risk identification associated with ground movements. The methodology is based on the use of the Active Deformation Areas (ADA) detected by medium resolution radar satellite interferometry (Sentinel-1A and Sentinel-1B). The goal is to obtain a quick and semi-automatically classification of the ADAs according to the probable geological phenomena origin (landslides, rockfalls and subsidence).</p><p>This ADA classification is based on current data (DTM and geology) and easy to implement with GIS, takes in account: (i), landslide inventories, to allow the direct validation of the geological phenomenon; (ii) geology -information of the geological units type-; (iii) slope terrain -morphology-, determines the classification of the movement cause, depending on the slope, they are more or less prone to the generation of geological phenomena (e.g. slopes <35º: landslides); and (iv) land uses, determines the potential impact on vulnerable areas (e.g. high, in urbanized areas; low, in natural environments). This methodology provides an ADA first geological susceptibility categorization that allows optimizing and prioritizing efforts in detailed geological and geomorphological characterization works.</p><p>The clustering of scattering points gave a result of 361 ADA (over an area of around 2,000 km<sup>2</sup>), 145 was classified as potentially generated by a geological phenomenon (126 susceptible to landslides, 7 as rockfalls, 7 as subsidence and 5 as landslides or rockfalls) and 215 were classified as other causes.</p><p>Ideally, validation is based on contrasting the ADA with actual inventory data. However, the lack of complete and exhaustive inventories require validation based on classic methods such as photointerpretation and field work. All areas were checked by means of geomorphological analysis to ensure their susceptibility: 143 has identified as caused by geological phenomena, 153 has related with geological depositional process (rocky ground) and 65 has discarded.</p><p>This work has been supported by the European Commission under the Interreg V-A-POCTEFA programme (grant no. Mompa – EFA295/19).</p>

scholarly journals Identification of a 17th-century tsunami deposit on the northern Hidaka coast, Hokkaido, northern Japan

2017 ◽  
Vol 56 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Yasuhiro Takashimizu ◽  
Kenji Nishina ◽  
Gentaro Kawakami ◽  
Yoshiki Sato ◽  
Satoshi Okamura ◽  
...  
Keyword(s):  
17Th Century ◽  
Tsunami Deposit ◽  
Northern Japan
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