Effect of Finite Frequency Bandwidth Limitation on Evaluations of Seismic Radiation Energy of the 1999 Chi-Chi Earthquake
Based on the £s−2 and £s−3 source models, we explore the effect on estimates of seismic radiation energy, Es , caused by finite frequency bandwidth limitation of source spectra. Let fc be the corner frequency of a source spectrum and fu and fc are, respectively, the upper and lower bounds of a frequ...
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| Format: | Article |
| Language: | English |
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Chinese Geoscience Union
2007-01-01
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| Series: | Terrestrial, Atmospheric and Oceanic Sciences |
| Subjects: | |
| Online Access: |
http://tao.cgu.org.tw/images/attachments/v183p567.pdf
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| Summary: | Based on the £s−2 and £s−3 source models, we explore the effect on estimates of seismic radiation energy, Es , caused by finite frequency bandwidth limitation of source spectra. Let fc be the corner frequency of a source spectrum and fu and fc are, respectively, the upper and lower bounds of a frequency band in use. Results show that the effect depends on fu/fc and fl/fc , and Es is under-estimated when fl > 0 and fu < ¡_. When fu/fc < 20, the effect is sensitive to both fl/fc and fu/fc for the £s−2 source model, but mainly to fl/fc for the £s−3 model. When fu/fc > 20, the effect is insensitive only to fu/fc for the two models. Let Es¡¦ be the seismic radiation energy estimated without removal of finite frequency bandwidth limitation. Results show: (1) Es¡¦/Es first slightly increases and then decreases with increasing fc ; or (2) Es¡¦/Es monotonously decrease with increasing fc. For the 1999 Ms 7.6 Chi-Chi earthquake, Taiwan, Es was under-estimated by Hwang et al. (2001), and the degree of under-estimates varies from station to station. |
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| ISSN: | 1017-0839 2311-7680 |