Multiplet-clustering

Eisenberg, A. Hird, B. Moore, R.B. A new multiplet-cluster model for the morphology of random ionomers. Macromolecules 1990,23, 4098. 

The multiplet analysis provides information on the micro structures in the seismic cloud. However, it does not give knowledge of absolute locations of individual multiplet clusters with the same order of precision to the relative location of events in a multiplet cluster. Moriya et al. (2002) proposed the multiplet-clustering method" to reduce the location error of multiplet clusters using the technique of clustering analysis. In this method, the waveforms of events in a multiplet group are stacked, and similar phases of the stacked waveforms are compared in time domain. Then, relative arrival time differences (i.e. relative locations between the stacked events) are more precisely determined. 

Structure of the seismic line estimated by the multiplet-clustering analysis... 

Figure 8 shows a result of the multiplet-clustering analysis applied to the multiplet groups in the microseismic structure shown in Figure 3. The 97 multiplet clusters are plotted in this figure. Relative locations between clusters are determined with error less than 6 m, while the location error for the JHD (Joint Hypocenter Determination) mapping shown in Figure 3 is about IS m.

The multiplet and multiplet-clustering analysis methods have been used to resolve the detailed microstructure of the seismic line which appeared at the early stage of the stimulation. The microstructure consists of the sub parallel multiplet planes. This result suggests that natural joints which are oriented to the directions most easy to slip, were stimulated by the injection. Because the structure developed stepwise corresponding to the... 

ESTIMATION OF FRACTURE PLANES BASED ON MULTIPLET-CLUSTERING ANALYSIS... 

The multiplet-clustering analysis is a method to estimate relative positions of the multiplet clusters as well as the relative source locations within individual multiplets (Moriya et al., 2CK)3). We have applied the multiplet-clustering analysis to the induced microseismic events as following procedures. 

Figure.3. Source locations of multiplets determined by (a) JHD and (b) multiplet-clustering analysis. Closed boxes along well describe the permeable fracture zones detected by well loggings. Thick line denotes fracturing well GPKl. The casing shoe is at the depth of2,850m.

Multiplet-clustering Analysis Reveals Structural Details within Seismic Cloud at the Soultz Geothermal Field, France. Bull. Seismol. Soc. Am. (to be published)... 

EHM Model. The Eisenberg-Hird-Moore (EHM) model or multiplet/ cluster model, incorporating both morphological and mechanical features, is also based on the existence of ionic aggregates, ie, multiplets (26). In the EHM model, it is assumed that the saxs peak is a result of interparticle scattering along the line suggested in References 22 and 23. 

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