著者

音田 功

出版者

東京大学地震研究所

雑誌

東京大學地震研究所彙報 = Bulletin of the Earthquake Research Institute, University of Tokyo (ISSN:00408972)

巻号頁・発行日

vol.40, no.3, pp.613-623, 1962-11-30

---

The Northern Miyagi Earthquake on April 30th, 1962 shook almost the same area as the Northern Rikuzen Earthquake on May 12th, 1900 with almost equal intensity The writer compared both earthquakes with one anothor and reached the following conclusions. Magnitude: The magnitude of the 1900 earthquake was larger than that of the later one by about two thirds, deduced by means of Kawasumi's method from the area of the isoseismals. The magnitudes Mk and M in the later one were deduced as 3.6 and 6.6, respectively (Fig. 2). Epicentre: The epicentre of the present one was determined in the neighbourhood of 38°45'N and 141°08'E, from the analysis of the record of the strong motion seismometer at Ishinomaki Weather Station. Therefore, that of the later one was about 20 km distance north from that of the previous one (Fig. 3). It was also ascertained that earthquakes seldom.occur in the northern part of Sendai Plain, although someone doubted its exsitence in that area. Number of after-shocks felt: Twenty-four after shocks were felt up to May 31st in the case of the former earthquake at Ishinomaki, while thirteen up to May 19th in the present earthquake. It was considered that this difference was caused by the dissimilar magnitute and epicentral distance from one another. Many abnormal after-shock were felt at the Hosokura Mine (Table III), compared with those felt at Ishinimaki (Table II) and Tsukidate (Table IV). Characteristics of the earthquake motion: The gravestones at Sekiun Shrine, Matsuyama Town, were studied. There were some gravestones which were rotated counterclockwise in the past earthquake, while such rotations of the gravestones could not be discerned in the case of the present one. It was inferred that this difference resulted from that of the epicentral distance and the magnitude.

著者

音田功

雑誌

地震研研究所彙報

巻号頁・発行日

vol.40, pp.613-623, 1962

被引用文献数

1

著者

太田 裕 音田 功 前川 博

出版者

東京大学地震研究所

雑誌

東京大学地震研究所彙報 (ISSN:00408972)

巻号頁・発行日

vol.46, no.6, pp.1397-1413, 1969-03-17

---

A large earthquake occurred to the south of Cape Erimo, Hokkaido, at about 9 h 49 m (JST) on May 16, 1968, and severely shook the Tohoku and Hokkaido areas. According to the Japan Meteorological Agency, the epicenter of this shock is 40°7N, 143:7E and 20km depth, and the magnitude 7.8 on the Richter scale. After about ten hours of this main shock, the largest aftershock (M=7.4) occurred at the location 41°4N, 143°3 E and 20km depth. Recently, the southern part of Hokkaido was rocked by two huge earthquakes, one was the Off-Tokachi earthquake of March 4, 1952 (M=8.1), and the other the Off-Hiroo earthquake of April 23, 1962 (M=7.0) (cf. Figure 1).