it is very important to study and simulate s-wave structure for near surface (alluvium parts, in particular) owing to its direct relationship to urban facilities in geotechnical and earthquake engineering studies. so, in seismic microzonation, the first step is to study and identify s-wave pattern in alluvium in order to categorize different parts of cites according to s-wave velocity. current ...

in exploration seismology, migration refers to a multi-channel processing step that attempts to spatially re-position events and improve focusing. before migration, seismic data is usually displayed with traces plotted at the surface location of the receivers and with a vertical time axis. this means that dipping reflections are systematically mispositioned in the lateral coordinate and the ver...

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...

many steps of seismic data processing sequence suppose that data sets are sampled in time and spatial dimensions uniformly. today, this assumption is true but only in time dimension. modern seismic exploration equipment permits seismic data sets to be sampled uniformly and densely in time dimension. however, along spatial dimension uniform and dense sampling are not possible because of operatin...

Seismic image and velocity models were obtained from a newly conducted seismic survey around the Integrated Ocean Drilling Program (IODP) Japan Trench Fast Drilling Project (JFAST) drill site in the Japan Trench. Pre-stack depth migration (PSDM) analysis was applied to the multichannel seismic reflection data to produce an accurate depth seismic profile together with a P wave velocity model alo...

Coda-wave interferometry is a technique to detect small seismic velocity changes using phase changes in similar waveforms from repeating natural or artificial sources. Seismic interferometry is another technique for detecting seismic velocity changes from cross-correlation functions of ambient seismic noise. We simultaneously use these two techniques to clarify seismic velocity changes at Sakur...

The Initial stages of velocity model building (VMB) start off from smooth models that capture geological assumptions of the subsurface region under analysis. Acceptable velocity models result from successive iterations of human intervention (interpreter) and seismic data processing within complex workflows. The interpreters ensure that any additions or corrections made by seismic processing are...

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. ...

The instrumental seismic intensity of Japan Meteorological Agency (JMA) uses three types of filters which consist of high-cut, low-cut and period functions. An extended function of the low-cut filter is used to evaluate the effect of long-period range on seismic intensity in the paper. An asymptotic filter processing of acceleration in the extended function is proposed to express seismic intens...