研究生: |
趙子凱 |
---|---|
論文名稱: |
集集地震前後震波衰減強度變化之研究 |
指導教授: |
陳光榮
Chen, Kuang-Jung |
學位類別: |
碩士 Master |
系所名稱: |
地球科學系 Department of Earth Sciences |
論文出版年: | 2001 |
畢業學年度: | 89 |
語文別: | 中文 |
論文頁數: | 73 |
中文關鍵詞: | 集集地震 、震波衰減 、時間變化 |
論文種類: | 學術論文 |
相關次數: | 點閱:183 下載:8 |
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摘 要
1999年九月二十一日一個規模超過7.0的大地震(Mw=7.7,ML=7.3)發生在台灣中部靠近集集鎮附近。到目前為止起碼超過15,000個餘震被記錄到。其中有200個以上的有感地震,規模大於6.0以上則有十個之多,是有史以來餘震最多的一個。在本研究中,我們分析發生在餘震區內的地震紀錄,計算從主震前20個月至主震後9個月內,該區域內衰減強度的時間變化,利用每一個測站量測的S波最大振幅所得出的的地區規模(local magnitude,ML),與平均地區規模作比較。首先分析各測站的規模差異量delta ML隨時間變化情形,並比較各測站在震前、震中及震後delta ML)的平均值變化情形。結果顯示,餘震區內在主震後有十個測站的(delta ML值降低,有五個測站delta ML值增加。其次分析delta ML的空間分佈,發現台灣地區的delta ML在主震前後並沒有太大的改變,反而在餘震區內則有顯著的變化。最後計算出餘震區的 1/Qs 值在主震後比主震前略為增加。
參考文獻
Anderson, J. G. and S. Hough, 1984, A model for the shape of the Fourier amplitude spectrum of acceleration at high frequencies, Bull. Seism. Soc. Am. 74, 1969-1993.
Blakeslee, S., P. Malin and M. Alvares,1989, Fault-zone attenuation of high-frequency seismic waves, G. Res. Lett. l6, 1321-1324.
Brune, J. N., 1970, Tectonic stress and the spectra of seismic shear waves from earthquakes, J. Geophys. Res. 75, 4997-5009.
Chen, K. J. , Y. H. Yeh, H. Y. Yen and C. H. Lin, 1995, Seismological studies in the Chinshan fault area, Jour. Geol. Soc. China 38, 335-353.
Gusev, A. A., and V. K. Lemzikov, 1985, Properties of scattered elastic waves in the lithosphere of Kamchatka: Parameters and temporal variations, Tectonophysics, 112, 137-153.
Jin, A., 1981, Duration of coda waves and the back-scattering coefficient, paper presented at the Symposium on Seismology in China, Shanghai, China.
Jin, A., and K. Aki, 1986, Temporal change in coda Q before the Tangshan earthquake of 1976 and the Haicheng earthquake of 1975, J. Geophys. Res., 91, 665-673.
Ma, K. F., C. T. Lee, Y. B. Tsai, T. C. Shin, and Jim Mori, 1999, The Chi-Chi, Taiwan Earthquake: Large surface displacements on island thrust fault. EOS, 80, 605-611.
Sato, H., 1986, Temporal Change in Attenuation Intensity Before and After the Eastern Yamanashi Earthquake of 1983 in Central Japan, J. Geophys. Res. 91, 2049-2061.
Sato, H. and I. S. Sacks, 1989, Anelasticity and thermal structure of the oceanic upper mantle: Temperature calibration with heat flow data, J. Geophys. Res. 94, 5705-5715.
Sekiguchi, S., 1991, Three-dimensional Q structure beneath the Kanto-Tokai district, Japan, Tectonophysics 195, 83-104.
Ukawa, M., M., Ishida, S. Matsumura, and K. Kasahara, 1984, Hypocenter determination method of the Kanto-Tokai observation network for micro-earthquakes(in Japanese), Res. Note. Nat. Res. Cent. Disaster Prev., 53, 1-88.
Wang, C. Y., 1988, Calculations of Qs and Qp using the spectral ratio method in the Taiwan area, Proc. Geol. Soc. China 3l, 81-98.
Ward R. W. and C. Y. Young, 1980, Mapping seismic attenuation within geothermal systems using teleseisms with application to the Geysers-Clear lake region, J. G. R. , 85, 5227-5236.
馬國鳳, 1999, 由地震活動及地震紀錄分析921集集大地震, 國立中央大學地球物理研究所網站.
張建興, 吳逸民, 辛在勤, 王乾盈, 蕭乃祺, 1999, 集集大震初始破裂之探討, 中國地球物理學會: 集集大地震特輯.