- 著者
-
功刀 卓
青井 真
中村 洋光
藤原 広行
森川 信之
- 出版者
- SEISMOLOGICAL SOCIETY OF JAPAN
- 雑誌
- 地震 第1輯 (ISSN:00371114)
- 巻号頁・発行日
- vol.60, no.4, pp.243-252, 2008
- 被引用文献数
-
20
A new calculation method is proposed for a real-time seismic intensity indicator (<i>I</i><sub>r</sub>), whose concept is similarly to the JMA seismic intensity (<i>I</i><sub>JMA</sub>)defined by Japan Meteorological Agency. With the increasing requirements of earthquake early warning (EEW) system, it is much more obvious that <i>I</i><sub>JMA</sub> has a real-time delay since the <i>I</i><sub>JMA</sub> needs a filtering operation in frequency domain. In order to improve the real-time calculation suitable for the EEW system, a new real-time seismic intensity indicator, <i>I</i><sub>r</sub> (real-time seismic intensity), is defined by using an approximating filter in time domain instead of the original filter in frequency domain. This indicator, <i>I</i><sub>r</sub>,can be calculated as a time series on real-time and its maximum value, <i>I</i><sub>a</sub> (approximate seismic intensity), corresponds to an approximate value of <i>I</i><sub>JMA</sub>. The relationships between <i>I</i><sub>JMA</sub> and <i>I</i><sub>a</sub> value are examined by means of using a large number of strong motion records. Results show that <i>I</i><sub>a</sub> value estimates <i>I</i><sub>JMA</sub> with reasonable accuracy in wide intensity ranges. For a small computing system like a strong-motion seismograph, it is easier to process <i>I</i><sub>r</sub> than processing <i>I</i><sub>JMA</sub>. Therefore, <i>I</i><sub>r</sub> is suitable for using in an EEW system based on the concept of JMA seismic intensity.