Application Of Q Tomography In The Sumatra,Indonesia

Q(quality factor)is one of the characterization indicators describing the absorption of seismic waves by viscoelastic media,and is more sensitive to underground anomalies/structures or fluid-containing regions than other parameters.It can be used for identification and interpretation of rock properties,faults and fluid-bearing distribution.Therefore,it is significant to estimate Q of underground media for finding hidden oil and gas reservoirs,predicting lithology,and studying crustal structures.Q tomography is widely used in earthquakes.In this paper,Q tomography method in the frequency domain is applied to wide-angle seismic data for obtaining attenuation model results,combined with known velocity information to explain the geology of the study area.In this paper,we first introduces the principles of spectral ratio Q tomography,and briefly describes the geological background of the research area in the Sumatra subduction zone and the data collected in the research area;Secondly,we illustrate the steps and parameters in Q tomography.Finally,we perform geological interpretation of the attenuation model in the study area based on the Q model.The attenuation model has high resolution in the shallow layer and the low resolution areas in the deep layer,and has a certain correlation with the velocity model.The results show that the 96 ° fault zone above 10 km in the oceanic plate has large attenuation.The attenuation of the accretionary wedge is smaller than that of the sedimentary layer,and the attenuation of the oceanic crust is the smallest.Therefore,the area near the trench where the fault zone and the thickened oceanic crust exist is relatively large,and the deep layer is relatively small,while the shallow layer near Simeulue Island has small attenuation and the deep layer has large attenuation.