Diatom assemblages within tsunami deposit from the 2011 Tohoku-oki earthquake along the Misawa coast, Aomori Prefecture, northern Japan

Lithology and microfossil biostratigraphy beneath the marshes of a central Oregon estuary limit geophysical models of Cascadia megathrust rupture during successive earthquakes by ruling out >0.5 m of coseismic coastal subsidence for the past 2000 yr. Although the stratigraphy in cores and outcrops includes as many as 12 peat-mud contacts, like those commonly inferred to record subsidence during megathrust earthquakes, mapping, qualitative diatom analysis, foraminiferal transfer function analysis, and 14C dating of the contacts failed to confirm that any contacts formed through subsidence during great earthquakes. Based on the youngest peat-mud contact’s distinctness, >400 m distribution, ∼0.6 m depth, and overlying probable tsunami deposit, we attribute it to the great 1700 CE Cascadia earthquake and(or) its accompanying tsunami. Minimal changes in diatom assemblages from below the contact to above its probable tsunami deposit suggest that the lower of several foraminiferal transfer function reconstructions of coseismic subsidence across the contact (0.1–0.5 m) is most accurate. The more limited stratigraphic extent and minimal changes in lithology, foraminifera, and(or) diatom assemblages across the other 11 peat-mud contacts are insufficient to distinguish them from contacts formed through small, gradual, or localized changes in tide levels during river floods, storm surges, and gradual sea-level rise. Although no data preclude any contacts from being synchronous with a megathrust earthquake, the evidence is equally consistent with all contacts recording relative sea-level changes below the ∼0.5 m detection threshold for distinguishing coseismic from nonseismic changes.

Download Full-text

Female Settling Pattern and Polygynous Breeding in a Great Reed Warbler Population in Aomori Prefecture, Northern Japan

Japanese Journal of Ornithology ◽

10.3838/jjo.44.157 ◽

1995 ◽

Vol 44 (3) ◽

pp. 157-168

Author(s):

Eiichiro URANO

Keyword(s):

Great Reed Warbler ◽

Reed Warbler ◽

Aomori Prefecture ◽

Northern Japan

Download Full-text

Pit Houses of Asia – A Japanese Phase

American Antiquity ◽

10.2307/277043 ◽

1953 ◽

Vol 18 (3) ◽

pp. 261-262

Author(s):

David W. Chase

Keyword(s):

North America ◽

Air Force ◽

River Valley ◽

American Antiquity ◽

Old World ◽

Archaeological Work ◽

Air Force Base ◽

Aomori Prefecture ◽

Northern Japan

The discussion of pit houses in the Old World and in North America by Hiroshi Daifuku (American Antiquity, Vol. 18, pp. 1-7) prompts me to add a note concerning certain pit house sites which I explored in northern Japan during the spring and summer of 1951.While searching the Yamagawa River Valley near Furumaki-machi in Aomori Prefecture for early Jomon sites, I encountered several pit house village sites. I had previously been advised of the general location of these by Major Howard McCord, formerly of Misawa Air Force Base, who had done considerable archaeological work in that region.

Download Full-text

Possible explanations on the formative processes of the Tsugaru-Juniko landslide, northern Japan

10.5194/egusphere-egu2020-6609 ◽

2020 ◽

Author(s):

Ching-Ying Tsou ◽

Daisuke Higaki ◽

Kousei Yamabe ◽

Tomo Kiru ◽

Takayoshi Sasagawa ◽

...

Keyword(s):

High Resistivity ◽

High Porosity ◽

Resistivity Tomography ◽

Internal Structures ◽

Radial Cracks ◽

Irregular Topography ◽

Pumice Tuff ◽

Aomori Prefecture ◽

Landslide Deposit ◽

Northern Japan

Identification of complex surficial and internal sedimentological characteristics of landslide deposits can provide insights into the emplacement mechanisms of mass movements. In this study, deposits of the Tsugaru-Juniko landslide, which was historically recorded triggered by an earthquake in 1704 (Imamura, 1935), in Aomori Prefecture, Japan were investigated. This landslide extended about 2 km from east to west with a volume of about 108 m3 (Furuya et al., 1987), of which deposit is represented by irregular topography and several lakes on and around the rim of it. We conducted field geological and geomorphological surveys and made geomorphological and geophysical analyses using a 1-m resolution LiDAR-DEM and 2D electrical resistivity tomography (ERT) measurement (10 m spacing of electrodes) over a 450 m wide landslide deposit. In plain view, the landslide deposit exhibits quite different features between its northern and southern parts, and each shows a clear sequential distribution of various features. At the northern part, the translation zone is characterized by hummocks and debris lobes containing mixtures of poorly sorted, angular, blocky rock debris of andesitic tuff. Prominent features on the debris lobes are debris-flow-ridges with lobate-shaped aprons extending NW to the downslope. In the accumulation zone, slope surface upheavals of compression origin and radial cracks are observed in the front part of the landslide. At the southern part, as compared to those features observed at the northern part, the slope is commonly marked by transverse ridges, oriented NE-SW, with prevalent steep cliffs on both sides, but generally steeper on the east. The ridges are separated from one another by trenches, elongated across the slope. Based on the distributions of these features, possible explanations on the formative processes of the landslide are complex associated with flowing and sliding at northern and southern parts, respectively. However, geological evidences from its internal structures are rare, ERT survey at the northern part of the landslide deposit reveals that up to 30-m-deep high-resistivity anomaly is associated with the landslide deposit, and low-resistivity anomaly with the bedrock consisting of pumice tuff, as also confirmed in the field. This may result from the high porosity of landslide deposit, because the displaced material deposited loosely.

Download Full-text

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

10.5194/egusphere-egu2020-7824 ◽

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

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&#160;MW Tohoku-oki earthquake, which caused massive damage along the coastlines.The 2011 Tohoku-oki tsunami overtopped the coastal defense walls with waves of 6-10&#160;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 &#8211; 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.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 &#8220;invisible&#8221; tsunami layer exceeding the limits of sandy deposits or the deposition in similar sedimentary textures, capturing a broader picture of the event.

Download Full-text

Sexual dimorphism in the size of bulbous nasal tubes of yellow goosefish Lophius litulon off Aomori Prefecture, northern Japan

NIPPON SUISAN GAKKAISHI ◽

10.2331/suisan.17-00031 ◽

2018 ◽

Vol 84 (1) ◽

pp. 130-132

Author(s):

YUHEI TAKEYA ◽

TETSUYA TAKATSU ◽

TOMOYUKI YAMANAKA ◽

YASUTOKI SHIBATA ◽

MITSUHIRO NAKAYA

Keyword(s):

Sexual Dimorphism ◽

Aomori Prefecture ◽

Northern Japan

Download Full-text

When global and local culture meet

Language Problems & Language Planning ◽

10.1075/lplp.37.2.04rap ◽

2013 ◽

Vol 37 (2) ◽

pp. 179-196

Author(s):

Ian Rapley

Keyword(s):

Cultural Differences ◽

World View ◽

Nation Building ◽

Local Culture ◽

Local Identity ◽

Arts And Culture ◽

Global And Local ◽

Aomori Prefecture ◽

Rural Part ◽

Northern Japan

In the 1920s Aomori prefecture, a rural part of northern Japan, a group of Esperanto clubs emerged as a sub-part of a “local arts movement”. This movement was an attempt to counter a perception of underdevelopment through the cultivation of local arts and culture together with a simultaneous engagement with global and transnational ideas such as Esperanto. By studying this unexpected manifestation of internationalism (as well as debates regarding the local/global relationship) it is argued that Esperanto represented a cosmopolitan world view that retained explicit respect for local and cultural differences, a “rooted cosmopolitanism”. This enabled the residents of Aomori to imagine an alternative to the process of modern nation building in which their local identity was seen as a remnant of an undesirable past.

Download Full-text