The seismic activities around the Sinmoe-dake and the Takatiho-no-mine are discussed on the basis of the data obtained by the seismological observation networks of the Kirisima Volcano Observatory (KVO), a branch station of Earthquake Research Institute. Almost all of the earthquakes occurred in these area are ultra-micro earthquakes and no felt shocks occurred during 1965 to 1973. A mean number of earthquakes per day of the Sinmoe area is smaller than 0.5 except during the years, 1967, 1968 and 1969. The occurrence of earthquakes in these three years does not fit to a Poisson distribution, but those in the other years fit. The seismic activity in this area was high in 1967, 1968 and 1969, but becomes lower since 1968. A mean number of earthquakes per day of the Takatiho area is larger than 1.0 except 1968, and the occurrence of earthquakes in this area does not fit to a Poisson distribution. The number of earthquakes per day in this area is several to ten times larger than those of the other areas in and near the Kirisima volcanoes.

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Earthquakes occurred in and near the Takatiho volcano are charactrized by the very shallow depth of their hypocenter. An earthquake swarm which has deeper focus than usual one occurred on June 17, 1973. Thirty shocks were recorded for five hours, and further twenty-two shocks observed from June 18 to August 25, 1973. The focal depth of these earthquakes is determined around -10 km from the mean sea level (MSL) using the data of the Kirisima Volcano Observatory (KVO). The depth around -10 km is several kilometers deeper than that for earthquakes which have usually occurred in this area. Some earthquake swarms in this area have been observed since 1968, but the focus of these earthquakes is shallower than -5 km from MSL. No such relatively deeper earthquakes and/or earthquake swarms as observed on June are not recognized. The number of earthquakes per day of this swarms is 0.9. This value is very small as compared to that of the other swarms which have occurred in the Takatiho area. But the magnitude of the shocks is relatively large.

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The greater parts of aphanitic dark grey Togawa lava occur in underground. Its areal distribution is estimated about 40 km² mainly by boring data. Akai volcano is the source of Togawa lava and mainly consists of reddish scoria. It has a crater about 0.5km, across, the floor of which is cultivated. Akai volcano has first erupted a lava flow and then formed a small cinder cone. Akai volcano is closely connected with the neighbouring Oomine volcano in types of volcanic structure and eruptive activity. Akai and Oomine volcanoes may be regarded as parasitic cones of Aso gigantic caldera volcano.

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Radiometric ages have been determined over the samples of Apollo 11, 12, 14, 15, 16, and 17 rocks and soils. From the age data of the lunar materials it is attempted to initiate a framework for a lunar chronology. The ages for the mare basalts are : Oeeanus Procellarum 3.2-3.4 b.y.; Mare Imbrium 3.3-3.4 b.y.; Mare Tranquilitatis 3.5-3.8 b.y.; Mare Serenitatis 3.7-3.8 b.y.; pre-Mare Imbrium 3.9-4.0 b.y. For the highland anorthosites and basalts : Hadley-Apennine highlands 3.3-3.4 b.y.; Taurus-Littrow valley 3.7-3.8 b.y.; Descartes highlands 3.8-3.9 b.y.; Fra Mauro hills～3.90 b.y.; Apennine Mountains～4.1 b.y. The moon originated about 4.6 b.y. ago. The outermost layers of the moon must have been very hot about 4.6 b.y. ago, by virtue of conservation of accretional energy; as based on the whole-rock and soil model Rb-Sr ages of 4.6 b.y. Cooling within the outer layers commences after the period of intensive rapid heating.

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