著者

益川 敏雄 表 俊一郎 久保寺 章 三浪 俊夫

出版者

日本地熱学会

雑誌

日本地熱学会誌 (ISSN:03886735)

巻号頁・発行日

vol.1, no.1, pp.3-14, 1979-06-30 (Released:2009-08-07)

参考文献数

5

被引用文献数

1

---

Recently, the Hatchobaru geothermal electric power station of Kyushu Electric Power Co. started its commertial operation on June 1977, under the prescribed power of 50, 000KW. In prior to the completion of the full scale Hatchobaru Power Station, a geothermal power station had been operated since August 1963 at Ohtake, about 2 km distant from the new station to the north. Together with the increase in the development of power production it was planned to improve the micro-earthquake observation network. A new network is composed by one base station and 6 branch stations distributed within an area of 20×20km, in which the Hatchobaru station is acting as the base station locating nearly in the center of the other stations. Each branch station is equipped with one vertical seismometer and is connected to the base station by telephone lines. In the base station all neccesarry devices for micro-earthquake observations are prepared including memory unit, trigger unit, amplifying unit, for-each respective station and a cloock system as well as a recording system. The recording system in Hatchobaru base station is so arranged that the six seismograms of all the seismic stations could be reproduced on one sheet of paper side by side. In doing so reading of seismograms and locating of epicenters could be realized most easily with high acculacy. In this report there are described the newly developed telemeter system for observing the micro-earthquakes in the Hatchobaru geothermal area, together with the some results obtained in the course of the first 8 months test run. These results fairly a satisfactory operation.

著者

三浪 俊夫 久保寺 章 表 俊一郎 木下 保美

出版者

日本地熱学会

雑誌

日本地熱学会誌 (ISSN:03886735)

巻号頁・発行日

vol.3, no.1, pp.43-53, 1981-04-20 (Released:2010-02-05)

参考文献数

20

被引用文献数

1

---

The area around the Kujyu volcanic mountains that is locating just in the central part of Kyushu Island is named as the Hohi geothermal area. In this region, the Ohtake and the Hatchobaru geothermal electric power stations are currently in operation. In this region, the micro-earthquake observation system has been set up providing six satelite stations connected to the Hatchobaru central station by public cable lines and giving seismograph records displayed on one sheet of paper in the central station. The operation of this micro-earthquake system has started July 1977 with highly increased time accuracy.Analysis of the seismic records for the last two years has yield following results.i) In these two years, about 200 foci of the earthquakes that occurred in this region have been located. All of these earthquakes gave the magnitudes smaller than M=3. These earthquakes could be classified into two groups. One was a group of earthquakes that might be related to the characteristic tectonics in the geothermal area, and the other were the earthquake that may be related either to the earthquake swarm activity in the northern part of the Aso caldera or the aftershock activity of the Oita earthquake of 1975.ii) The micro-earthquakes that are proper to the geothermal area were seen arranged in a belt zone along fault lines that are developed clearly in this region. In this belt zone swarm type microearthquake activities were observed showing the short duration period of swarm occurrence and shifting the swarm activity from one place to another.iii) For the purpose of obtaining more accurate focal locations, re-determination of the foci of all these swarm earthquakes were carried out by the aid of the improved master event method.As the result of which, it was made clear that foci distribution of each of these earthquake swarm was bounded in a narrow volume having the horizontal and vertial dimensions of 500 m x 2 km, extending almost vertically.iv) With regard to these earthquakes in the swarm, the study was carried out for making clear the earthquake occurrence mechanism of these earthquakes. It was found that earthquakes that occurred in the area near the Aso caldera, showed a mechanism represented by the right-lateral fault movement and for the earthquakes that took place along the geological fault zone, they showed a normal fault type mechanism.v) Within the low gravity area represented by the Kujyu caldera, locating in the north-eastern part of the Kujyu mountain range, almost any micro-earthquake activity is not observed.

著者

表 俊一郎

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.15, no.5, pp.101-113, 1943

著者

表 俊一郎

出版者

公益社団法人 日本地震学会

雑誌

地震 第1輯 (ISSN:00371114)

巻号頁・発行日

vol.15, no.5, pp.101-113, 1943-05-18 (Released:2010-11-17)

参考文献数

5

著者

表 俊一郎 三宅 昭春 甲斐 直樹

出版者

公益社団法人 土木学会

雑誌

地震工学研究発表会講演概要 (ISSN:09134085)

巻号頁・発行日

vol.14, pp.77-80, 1976 (Released:2010-03-17)

参考文献数

17