減衰の遅い終期微動を伴う火山性地震について
スポンサーリンク
概要
- 論文の詳細を見る
Among the various type of volcanic earthquake and volcanic tremor, there are few type of volcanic earthquakes which including the coda wave vibration. The coda waves show slowly decaying for amplitude and have stationary period that the forms of them are resembled the damping free motion of seismometer pendulum. In this paper, writers call them convincingly "T-type earthquake". There are about sixty active volcanoes in Japan, but T-type earthquake has only been observed in the following six volcanoes namely Mt. Asamayama, Sakurajima, Mt. Tarumaeyama, Mt. Kusatsu-Shiranesan and Kuchinoerabujima. T-type earthquakes have a tendency to swarm, but its occurence is very rare. For example at Mt. Asamayama number of T-type earthquakes don't exceed 0.1% of the total number of volcanic earthquakes in recent 10 years. The form of T-type earthquake differs a little from volcano to volcano but it generally resembles to the B-type earthquake except the part of coda waves. Common feartures of coda wave of T-type earthquake are as follows: 1) Periods of coda waves are distributed among 0.2〜1.5 sec. 2)Damping coefficients "h" of coda waves are distributed among 0.003〜0.03. Coda wave has predominant amplitude in the horizontal component of perpendicular direction from the crater. Attenuation of amplitude of the coda wave with distance from the crater is larger than the case of the B-type earthquakes which is mainly composed of the seismic surface wave. From the above mentioned result, writers suggest that the coda wave of T-type earthquake has a character of seismic SH wave. Comparison of maximum amplitude of T-type earthquake which recorded at different point on the same volcano suggests that origin of these earthquakes are located at shallow beneath the crater, similar to the case of the B-type volcanic earthquake. The coda waves of T-type earthquake are considered to generate by the free oscillation of some source beneath the crater. It is also a worthy of note that T-type earthquakes is only observed at the andesitic volcano which has erupted the Phreatic type eruption or the Vulcanian type eruption in recent years and T-type earthquakes sometime swarmed when abnormal volcanic activity was observed.
- 1976-12-15
著者
関連論文
- 1923年関東地震の余震活動の総合的調査
- 広域の地震観測網で捕らえた平成12年(2000年)有珠山噴火開始前後の地震活動(2000年有珠山噴火 (3))
- 微小地震観測網で捉えた富士山の地震活動(日本火山学会 1981 年春季大会講演要旨)
- 桜島有村における傾斜観測
- 浅間山の火山性地震の2,3の特性 : 日本火山学会1977年度秋季大会
- 桜島有村の傾斜観測(2) : 日本火山学会1977年度春季大会
- 減衰の遅い終期微動を伴う火山性地震について
- 54. 減衰の遅い終期微動を伴う B 型地震について(日本火山学会 1975 年度秋季大会講演要旨)
- 火山用の機械式地震計と電磁式地震計の比較テスト (測器) -- (測器技術)
- A68 浅間山の最近の地震活動 : 7 月 24 日に発生した長周期の地震波を伴った地震について
- E41-09 房総沖海底地震計などで捉えられたマリアナ海底噴火に伴う T 波(第 2 報)
- 54. 桜島の傾斜計観測について(日本火山学会 1975 年度春季大会講演要旨)
- E41-11 浅間山における SO_2 放出量の自動観測(序)
- P02 1990 年浅間山小噴火活動の概要