著者

広野 卓蔵 佐藤 馨

出版者

気象庁気象研究所

雑誌

Papers in Meteorology and Geophysics (ISSN:0031126X)

巻号頁・発行日

vol.22, no.3-4, pp.177-193, 1971 (Released:2012-12-11)

参考文献数

5

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MSK震度階が我が国に適した震度階であるかどうかを試験するために,106の気象官署で, MSK震度とJMA震度の同時観測を1967年から1970年まで行った.このために作った調査表に地震時に観測した現象の項目をチェックして気象研究所に送り,著者等はそれによってMSK震度の決定を行った.地震を大地震と小地震に分けて,JMA震度と比較しながら統計を取った.その結果JMA震度は低震度に適し, MSK震度は高震度に適していることが分った.JMA震度3までの低震度をMSK震度になおす式はM=1.5J+1.5で,ここにMはMSK, JはJMA震度である.また大地震のときの両者の関係はM=1.5J+0.75と求められた.両者にはそれぞれ長所と短所があり,気象庁は両者を併用することが望ましい,すなわち,JMAは緊急報告用に,MSKは大地震の現地調査などに用いられる.

著者

湯村 哲男 広野 卓蔵 和達 清夫

出版者

公益社団法人 日本地震学会

雑誌

地震 第2輯 (ISSN:00371114)

巻号頁・発行日

vol.23, no.2, pp.99-121, 1970

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Spatial distribution of earthquake foci for the period from 1926 to 1968 in and near Japan were expressed in 16 maps each for a layer of 20-40km in thickness lying between 0 to 600km in depth. The maps show definitely the boundary lines and centers of local activities distinguishable in seismicity from each other. We named them seismic blocks. The centers of the shallow seismic blocks which crowd in a zone along the west side of the Japan trench can be traced down to 600km in depth. At first such centers move with increasing depth toward two junction areas of the island arcs of Kuril, NE-Japan and Izu-Bonin, that is, the Hokkaido and the Kwanto districts. From there they continue sinking to north for Hokkaido and to west for Kwanto making a dipping angle of 30°. Then their directions change abruptly by 90° at a depth of about 300km. From North Hokkaido one branch of the locus of the center goes into the Okhotsk Sea and the other into the Japan Sea along the coast of Primorye. On the other hand, the locus of the block center moving toward the west Kwanto turns to the south at that depth under Gifu Pref. for the Shikoku Basin, although a shorter branch goes northward into the Japan Sea. It is notable that few deep shocks occur in the middle of the Japan Sea. Considering the other geophysical and geological phenomena such as (1) the negative zone of isostatic anomaly of gravity lying along the Japan trench branches out to the junction areas in land, (2) the movement of the triangulation stations for the last 60 years or so amounts to about 3m to the north at Aomori Pref. in comparison with the Kui Peninsula, showing that two forces are acting in the respective areas in opposite directions, (3) the axis of mountain ranges made of metamorphic rocks which encounter the locus of the block center in Hokkaido and Central Honshu underwent severer bending, we conclude that the locus of the seismic block center expresses the location of the mantle current coming from the Pacific. itself.

著者

広野 卓蔵 末広 重二 古田 美佐夫 小出 馨

出版者

気象庁気象研究所

雑誌

Papers in Meteorology and Geophysics (ISSN:0031126X)

巻号頁・発行日

vol.19, no.2, pp.323-339, 1968-10-25 (Released:2012-12-11)

参考文献数

4

被引用文献数

1 2

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本研究は本邦の地震予知に関する研究の一環として,高感度地震計の市街地における地震観測方法の改善を最終目的としている。このため,気象庁が現用している電磁式地震計と同一性能の地中地震計を開発し,これを主として地盤の雑微動の実態を解明する目的で観測井(深さ200m)の掘削過程における各種深度面(10,20,50,100,150,200m)に設置して,それぞれ地上との同時比較観測を行った。本論文は観測資料の解析結果,また,地質調査資料について述べる。おもな帰結;(1) 高周波ノイズほど深さと共に減衰し,特に50mまでは著るしい。(2)0.5cps以下の低周波ノイズはほとんど減衰しない。(3) 周期1secの地震計による近地地震の観測を目的とする場合,50m程度の深さで著るしいSN比の改善が期待される。(4) 重錘落下や自動車の通過によるノイズは50mより深くなると問題にならない。

著者

湯村 哲男 広野 卓蔵 和達 清夫

出版者

公益社団法人 日本地震学会

雑誌

地震 第2輯 (ISSN:00371114)

巻号頁・発行日

vol.23, no.2, pp.99-121, 1970-06-28 (Released:2010-03-11)

参考文献数

18

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Spatial distribution of earthquake foci for the period from 1926 to 1968 in and near Japan were expressed in 16 maps each for a layer of 20-40km in thickness lying between 0 to 600km in depth. The maps show definitely the boundary lines and centers of local activities distinguishable in seismicity from each other. We named them seismic blocks. The centers of the shallow seismic blocks which crowd in a zone along the west side of the Japan trench can be traced down to 600km in depth. At first such centers move with increasing depth toward two junction areas of the island arcs of Kuril, NE-Japan and Izu-Bonin, that is, the Hokkaido and the Kwanto districts. From there they continue sinking to north for Hokkaido and to west for Kwanto making a dipping angle of 30°. Then their directions change abruptly by 90° at a depth of about 300km. From North Hokkaido one branch of the locus of the center goes into the Okhotsk Sea and the other into the Japan Sea along the coast of Primorye. On the other hand, the locus of the block center moving toward the west Kwanto turns to the south at that depth under Gifu Pref. for the Shikoku Basin, although a shorter branch goes northward into the Japan Sea. It is notable that few deep shocks occur in the middle of the Japan Sea. Considering the other geophysical and geological phenomena such as (1) the negative zone of isostatic anomaly of gravity lying along the Japan trench branches out to the junction areas in land, (2) the movement of the triangulation stations for the last 60 years or so amounts to about 3m to the north at Aomori Pref. in comparison with the Kui Peninsula, showing that two forces are acting in the respective areas in opposite directions, (3) the axis of mountain ranges made of metamorphic rocks which encounter the locus of the block center in Hokkaido and Central Honshu underwent severer bending, we conclude that the locus of the seismic block center expresses the location of the mantle current coming from the Pacific. itself.

著者

広野 卓蔵

出版者

一般社団法人日本建築学会

雑誌

建築雑誌 (ISSN:00038555)

巻号頁・発行日

vol.75, no.891, pp.601-605, 1960-11-20