the mixture of natural and artificial seismic sources with random distributions cause diffuse wave field with random amplitudes and phases called noise. when noise is analyzed in a long-term process, it contains surface waves which are spread in all directions. thus, ambient noise contains data relevant to the surface waves. in recent years, as broadband seismic networks have been distributed v...

Seven two-dimensional (2-D) seismic refraction lines were used to determine the thickness and geometry of a valley train outwash deposit of the Quaternary Henry Formation near Heyworth in southern McLean County, Illinois. These refraction data were collected and processed in 2-D, then imported into a Petrel, a three-dimensional (3-D) geological modeling software package. The 3-D geologic model ...

To better assess quality of 3-D tomographic images and to better define possible improvements to tomographic inversion procedures, one must consider not only data quality and numerical precision of forward and inverse solvers but also appropriateness of model parametrization and display of results. The quality of the forward solution, in particular, strongly depends on parametrization of the ve...

The objective of this work is to build an efficient algorithm (a) to estimate seismic velocity from time-migration velocity, and (b) to convert time-migrated images to depth. We establish theoretical relations between the time-migration velocity and the seismic velocity in 1 Page 1 of 23 GEOPHYSICS 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 3...

seismic inversion is a method that extracts acoustic impedance data from the seismic traces. sourcewavelets are band-limited, and thus seismic traces do not contain low and high frequency information.therefore, there is a serious problem when the deterministic seismic inversion is applied to real dataand the result of deterministic inversion is smooth. low frequency component is obtained from w...

The paper describes an integrated approach to seismic hazard assessment, which was applied for the Taiwan region. First, the theoretical seismic catalogue (2001-2050) for the Taiwan region had been calculated using the 4D-model (location, depth, time) for dynamic deformation of the Earth’ crust and 5D-model (location, depth, time, magnitude) for seismic process. The models were developed on the...