Annals of the Tohoku Geographical Association

On the Shore Type of the Tohoku District

Akio Mogi

1960 Volume 12 Issue 4 Pages 103-114
Published: 1960
Released on J-STAGE: October 29, 2010

DOIhttps://doi.org/10.5190/tga1948.12.103

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As the result of the consideration on the distribution of the shore type in the Tohoku District, the author recognized the followings.
(1) In the Japan Sea coast, several parallel bars are developing for many miles along the shore. On the other hand, in the Pacific coast, either one significant bar is existing or bar is absent entirely. The shore without bar in the Pacific coast exist in the bay such as the Sendai bay and the northern coast of the Shimokita Peninsula.
(2) The difference of the shore type between the Japan Sea coast and the Pacific coast occurs from the difference of the breaking type. In the Japan Sea coast, sea bottom gradients are smaller and initial wave steepness are greater than in the Pacific coast. So that in the Japan Sea coast, the tendency of spilling breaker is stronger than in the Pacific coast.
(3) In the bar coast, the size of bar of the open shore is burger than that of the secret shore, On the other hand, in without bar coast also, the bottom profile of the open shore has the terrace 3 meters in depth.
(4) The size of these bars is related to the gradient of the sea bottom shallower than 20 meters in depth.

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On the Measurement of the Frequency Belt of Weather Divide

Hiroshi Shitara

1960 Volume 12 Issue 4 Pages 115-119
Published: 1960
Released on J-STAGE: October 29, 2010

DOIhttps://doi.org/10.5190/tga1948.12.115

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Erosion and Deposition due to the Tsunami caused by the Chile Earthquake on May 24, 1960

Enzo Kon'no, Nobu Kitamura, Tamio Kotaka, Jun Kataoka

1960 Volume 12 Issue 4 Pages 120-127
Published: 1960
Released on J-STAGE: October 29, 2010

DOIhttps://doi.org/10.5190/tga1948.12.120

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The problems related with erosion and deposition due to the Tsunami caused by the Chile Earthquake on May 24, 1960 are briefly summarized in this report. The area where observations were made is the Takada-Matsubara beach and the vicinity in Iwate Prefecture.
Waves cussed by the Tsunami like oceanic waves and currents, is an important agency in modifying the geomorphological features of the land adjacent to the sea. This agency is subdivided, from its process, into three types of streams, namely, sheet-flow, linear-flow and eddy. Each of the processes is described on the observed features and are accompanied with illustrations.
Degradation and aggradation due to the Tsunami changes the landform by erosion, masswasting and deposition. These different processes, related with the three types of agencies above-mentioned, are discussed and accompanied with illustrations.
The Takada-Matsubara beach and bay-head bar of the Hirota Bay along the Sanriku coast of Iwate prefecture was damaged by and due to the after effects of the Tsunami. The beach extending from Wakinosawa to the Kesen River was cut into three parts, and the lagoon of Furukawa-numa, situated behind the bay-head bar, became united directly with the Hirota Bay.
The erosional processes and the deposits in the vicinity of the Takada-Matsubara beach are elucidated by the accompanying illustrations.

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[title in Japanese]

1960 Volume 12 Issue 4 Pages 128-129
Published: 1960
Released on J-STAGE: October 29, 2010

DOIhttps://doi.org/10.5190/tga1948.12.128

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