Gravity Measurements along the Lines of Precise Levels over Whole Japan by Means of a WORDEN Gravimeter.

Gravity survey in the Central Ranges, Honshu, Japan.

“…(1) TSUBOI et al (1955) and HAGIWARA (1967) noted a broad zone of large negative anomalies in the area of the Central Ranges. This broad zone is now resolved into two parts, one along the axis of the Hida mountain range and the other along the northern Fossa Magna (the Matsumoto sedimentary basin).…”

“…The land gravity data so far obtained through nation-wide measurements in Japan have been summarized by TSUBOI et al (1955), the GEOGRAPHICAL SURVEY INSTITUTE (GSI) (1964) and HAGIWARA (1967). Rather local gravity surveys have been carried out in Central Honshu by the Geological Survey of Japan (GSJ) (e.g., CHUJO and SUDA, 1972) and other institutions.…”

Geochemistry of lanthanides in basalts of Central Japan

“…The contours of earthquake depth ( 3 , 5) gravity isostatic anomaly (6) and heat flow (7) appear t o run approximately parallel with the elongation of the island a r c of Japan. Based on the parallelism between petrographic boundaries and contours of intermediate and deep seismic foci, Kuno (3) postulated that the depth of source of magmas below Japan increases from the Pacific Ocean to the Japan Sea side, namely, towards the continent.…”

Microearthquake Survey in Northeastern Honshu, Japan

“…This is the reason why northeastern (Tohoku) Honshu was chosen as an object of the Japan-US cooperative microearthquake survey. The survey was carried out for 20 days in October and November in 1967. In the Tohoku area of Honshu, a major tectonic structure, a remarkable geological line, was detected by a gravity survey (TSUBOI et al, 1956) as shown in Fig. 1.…”