Proximity, AE doublets are introduced as a new category of AE doublets in this paper. Proximity AE doublets have a similar wave form, and they occur in a succession with a short interval. Proximity, AE doublets have the second event that arrives before attenuation of the first event. Their interval is shorter than 1s. On the other hand, interval between events of the conventional AE doublets/multiplets ranges from some seconds to some days. Because of this short interval of the proximity AE doublets, relative location between AE sources can be estimated more accurately in the proximity AE doublets analysis than in the conventional AE doublets/multiplets analysis. This paper also describes a signal processing technique to detemline intervals of P-wave and S-wave between two events of proximity AE doublets. It is difficult to estimate similarity between the two waveforms and their interval because the two events overlap each other. Cepstrum analysis is applied to estimate both the interval and the similarity. Proximity AE doublets have one or two peaks in their cepstrum, and quefrencies of the peaks are intervals of P-wave and S-wave between the two events. Three-component AE signal is rotated in the directions of P-wave and S-wave, and data before the first S-wave arrival is replaced with zeros so that the intervals can be determined from the peaks in the cepstrum analysis. Cepstrums of these processed three-component AE signal can show intervals of P-wave and S-wave between the two events of proximity AE doublets.
ケプストラム解析による近接型AEダブレットの入力時間差推定法
JGeotherm_30(1)_37-47.pdf
(1.04MB)
