The Ryoke metamorphic and granitic rocks along the Median Tectonic Line (MTL) in the Misakubo area consist of gneisses, migmatitic granites and mylonitic rocks. The gneisses are mainly pelitic, psamitic and silicious. The migmatitic granites are leucocratic, and occur as veins or dyke-like forms ranging from a few centimeters to several tens of centimeter in the fine-grained gneisses. These rocks were metamorphosed under moderate to higher temperature part of the amphibolite facies. The mylonitic rocks are close to the MTL and consist of mylonitized fine-grained gneisses, K-feldspar porphyroblast mylonite gneisses (mylonitized migmatitic granites) and mylonitized diorite or quertz-diorite.
Based on the observation of progressive shearing and mylonitic fabrics under the microscope, pelitic, psamitic fine-grained gneisses and migmatitic granites are classified into seven types: A, without shear bands and mylonitic textures; From AB to B, increasing shear bands (shear band type of deformation); From BC through C to CD and D, protomylonitic texture to blastomylonitic textures (mylonite type of deformation).
The distribution of these types for the pelitic, psamitic gneisses and migmatitic granites in this area are as follows. From west toward the MTL the change of types are irregular. However, types C, CD and D are abundant close to the MTL. Furthermore, types C, CD and D occur considerably in the northern part, but they are nearly absent in the southern part of the area.
The unzonal structure of the type distribution along the MTL might support the view of Yamamoto and Masuda (1990), that mylonite zone formed prior to the formation of the MTL.

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The boundaries of Pacific, Philippine Sea, North America, Amur, and South China plates locate around Japanese Island arcs. Triple junction of plate boundaries off Boso acts as a controller on the strain of the Japanese Island arcs. Chuetsu Earthquake of October 2004 in Niigata Prefecture occurred under the extraordinary circumstance of the strain.
We examine relative plate convergence and earthquakes along the plate boundaries of Kuril Northeast Japan Arc along Kuril-Japan Trench, Ryukyu Arc along Ryukyu Trench and Taiwan, Izu Arc along Izu-Ogasawara-Mariana-Yap-Palau Trench, Southwest Japan Arc along Sagami-Suruga-Nankai Trough. The earthquakes from January 1997 to January 2005, reported on Monthly Report of Earthquakes and Volcanoes in Japan as main earthquakes around Japan and world by Japan Meteorological Agency were used. Convergent area in km² per year S_y, Euler latitude of ends of interval on plate boundary φ₁ and φ₂, and rate R of relative rotation along the plate boundary around Euler Pole in degree /million years relate as follow;
S_y = 0.7074 (sinφ₁ − sinφ₂) R
and area of dislocation Sƒ in km2 for earthquake with magnitude M is calculated as follow;
S_f = 10^{1.2M − 9.9}
Cumulative convergent areas ΣS_y, for relative plate motions and cumulative areas for dislocations ES_f with earthquakes along plate boundaries correlate well.
The earthquakes did not uniformly occur along the plate boundaries, and divition into stages is defined using the behavior of occurrence of earthquakes along the plate boundaries around Japanese Island arcs.

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Many low-frequency earthquakes were observed under Mt. Fuji from October 2000 to May 2001, and it was pointed out that the volcanic activity of Mt. Fuji might increase.
In order to monitor the volcanic activity, we performed precise relative gravity measurements over Mt. Fuji area by using LaCoste & Romberg gravimeters since 2002, and investigated temporal change of gravity over Mt. Fuji for three years.
The number of the low-frequency earthquakes has decreased since June 2001, and no significant gravity temporal changes were observed, however the data obtained form an important data base to investigate the future volcanic activity of Mt. Fuji.

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Molluscan thanatocoenoses are described on the basis of the Smith-McIntyre grab samples collected by Geological Survey of Japan during the autumn of 1977 in Suruga Bay, central Japan. The sampling points cover entire Suruga Bay, which contains various sedimentary settings, such as fan deltas (off Oi, Abe, and Fuji Rivers), a branch bay (Uchiura Bay), sand-wave dominant shelf (off Sagara), narrow shelf and steep slope (off Izu Peninsula), a topographic high (Senoumi Bank), a deep-sea basin (Senoumi Basin) and a trench (Suruga Trough) over 2,500 m water depth. Species composition of the molluscan thanatocoenoses is mainly controlled by the frequency of disturbance events such as rapid burial and bottom turbulence. Molluscan shell-remains are generally rare in the inner shelf of the fan deltas, but are characterized by the occurrence of tellinid bivalves (off Oi River) and solenid, pharid, and venerid bivalves as well as tellinids (off Abe River). These siphonate bivalves can escape from rapid burial during storm and flood events in the fan deltas. In the outer shelf and shelf break environments of the fan-delta margins, the molluscan thanatocoenoses are composed of deposit-feeding nuculoid bivalves, and lack any suspension-feeding bivalves such as Neopycnodonte cochlear, Cryptopecten vesiculosus, Glycymeris rotunda, Venus foveolata, and Limopsis belcheri, which are abundant in the outer shelf to shelf break of the other areas characterized by low sedimentation rate. Molluscan shell-remains in the slope and basin floor environments are generally rare and characterized by occurrences of deposit-feeding bivalves such as nuculoids, tellinids, and semelids, but the steep slope off Izu Peninsula and around Senoumi Bank are characterized by frequent to common occurrence of suspension-feeding bivalves, Limopsis belcheri and Limopsis aff. obliqua. This benthic faunal difference in the deep-sea environments may be related to the difference of bottom cohesiveness and bottom current conditions.

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