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Tsuruga, Kayoko; Kunitomo, Takahiro; Hasada, Yoko; Kumazawa, Mineo; Shigeta, Naotaka; Kasahara, Junzo
2004 AGU Fall Meeting Program and Abstract, S31C-05, 0 Pages, 2004/00
We are developing an active monitoring methodology named ACROSS (Accurately Controlled Routinely Operated Signal System) to detect any subtle temporal change of physical properties in the Earth's interiors (Kumazawa et al., 2000). ACROSS is a comprehensive measurement system to determine continuously the transfer function of a linear system by means of the coherent signals. The combination of ACROSS transmission and array observation allow us to obtain the transfer function with high S/N (ratio of signal to noise) and S/B (ratio of signal to bias) in space and time. In this paper, we briefly review the specifications of our seismic array and report the latest results of the data analyses.
Hasada, Yoko; Kumazawa, Mineo; Tsuruga, Kayoko; Kunitomo, Takahiro
AGU 2004 Fall Meeting, 0 Pages, 2004/00
We have developed a method to extract "events" localized in time domain from a transfer function in frequency domain, which is a basic analysis method of ACROSS(Accurately Controlled Routinely Operated Signal System)and referred to as the Sompi event analysis. Though the validity of the Sompi event analysis is confirmed through various numerical tests especially for analysis of dispersive wave, there are some problems in practical application. Here we introduce a revised procedure by means of weighted least squares fitting, which is based on maximum likehood estimation.