We determine upper mantle seismic velocity heterogeneities below Southern California from the inversion of teleseismic travel-time residuals. Teleseismic P-wave arrival times are obtained from three temporary passive experiments and Southern California Seismic Network (SCSN) stations, producing good raypath coverage. The inversion is performed using a damped least-squares conjugate gradient met...

[1] In this study, we analyzed the seismic phases S, SKS, and SKKS from 31 deep-focus earthquakes in the Tonga-Fiji region recorded in North America between epicentral distances of 85 and 120 . The differential traveltimes and amplitude ratios for these phases reveal clear epicentral distance trends not predicted by standard one-dimensional (1-D) reference Earth models. The increase of the S/SK...

In this paper, we are interested in determining the seismic velocity of a shallow under-ground layer from refraction traveltimes measures. We present a study case taken from an experimental seismic survey. The study case is a wide-angle seismic inversion using experimental traveltimes measures and based on ray tracing technique and genetic algorithms. The hypothesis on the velocity distribution...

the velocity data of seismic waves in a region has an important role in locating occurred events. information such as velocity ratio of vp/vs and velocity curves for pg, pn, sg, and sn phases directly affect the locating results. it is well known that the vp/vs ratio can be used to predict lithology, and that s-waves are sensitive to microcracks aligned by the present day stress field. also, th...

Geofluids is important for understanding volcanic and earthquake generation processes. In this study, we obtained a detailed seismic velocity structure in and around the Naruko volcano, northeastern Japan, using data from a dense seismic observation network. We found a distinct seismic low-velocity zone (LVZ) beneath the Naruko volcano, with a diameter of nearly 10 to 20 km in the lower crust. ...

One of the most effective ways to deal with source-generated coherent noise, which often contaminates seismic reflection records, is to record the data in the field using spatial sampling small enough to avoid aliasing the highest frequency components of the lowest-velocity surface wave energy. The offending noise can then be effectively estimated and removed by application of various processin...

[1] Variability of core-mantle boundary (CMB) structure is imaged at the kilometer to tens of kilometers scale by intensive waveform modeling of the ScP phase. Recordings of earthquakes in the Tonga-Fiji subduction zone from the small-aperture (10 km), high-frequency ( 2–4 Hz) Alice Springs Array in central Australia are used to document anomalous ScP waveform variations due to the presence of ...

As one of the main characteristics of seismic waves, apparent wave velocity has great influence on seismic responses of long-span suspension bridges. Understanding these influences is important for seismic design. In this article, the critical issues concerning the traveling wave effect analysis are first reviewed. Taizhou Bridge, the longest triple-tower suspension bridge in the world, is then...