This paper explores the relationship between velocity uncertainty and AVO-related seismic attributes in a dataset from the Blake Outer Ridge, offshore from Florida and Georgia. From an initial velocity model, several realizations were generated that are perturbations of the original velocity model. Prestack wave-equation migration was applied to the data for each velocity realization. In the mi...

We extend time-domain velocity continuation to the zero-offset 3D azimuthally anisotropic case. Velocity continuation describes how a seismic image changes given a change in migration velocity. This description turns out to be of a wave propagation process, in which images change along a velocity axis. In the anisotropic case, the velocity model is multi-parameter. Therefore, anisotropic image ...

A mathematical model is considered to investigate the behavior of horizontally polarized shear waves (SH-waves) in fluid saturated porous medium sandwiched between heterogeneous half-spaces. Heterogeneity in the upper half-space is due to linear variation of elastic parameters, whereas quadratic variation has been considered for lower half-space. The method of separation of variables and Whitta...

In a previous study published in this journal, the authors developed a comprehensive methodology for modelling the shear wave velocity profile in crustal rock, for purposes of seismic hazard assessment. The derived shear wave velocity profile was used to estimate the amplification and attenuation mechanisms in the transmission of seismic waves. The ability to conduct seismic hazard assessments ...

In this paper, we summarize some recent results of measurements of temporal changes of active volcanoes using seismic noise cross-correlations. We first present a novel approach to estimate volcano interior temporal seismic velocity changes. The proposed method allows to measure very small velocity changes (≈ 0.1%) with a time resolution as small as one day. The application of that method to Pi...

We investigated upper crustal structure with data from a dense seismic array deployed around Mount St. Helens for 2 weeks in the summer of 2014. Interstation cross correlations of ambient seismic noise data from the array were obtained, and clear fundamental mode Rayleigh waves were observed between 2.5 and 5 s periods. In addition, higher-mode signals were observed around 2 s period. Frequency...

north-east khorasan is one of the most active regions in the world because of is setting on the alpine-himalayan belt. historical and geological backgrounds suggest that this region has experienced many destructive earthquakes throughout history. compared with the historical background, the seismicity of the region, in the present century, is better known both from the macroseismic and instrume...

earthquakes travel times inversion for determination of velocity structure of crust is one of the most important objectives in seismology. in the simultaneous inversion method, the parameters of earthquakes and velocity model are determined initially and are improved during inversion steps. in this study, we have used more than 22000 calculated travel times for first arrivals of 6000 earthquake...