Spatial Variability of Shear Wave Velocity Using Geostatistical Analysis in Mashhad City, NE Iran

Abstract

Shear wave velocity (Vs) is one of the most important parameters of a geological model to assess the site effect and the ground response. In this paper the spatial variability of shear wave velocity in Mashhad capital city are investigated. For this purpose, 243 Vs profiles of different projects throughout the city were used. Based on the Vs profiles the iso-level maps of the Vs interfaces 300, 500, 750, 950 and 1200 m/s were obtained by kriging interpolation method. The best semivariogram models were obtained with changing the effective parameters and assessing the components of the models and spatial dependence. The best models for the entire interfaces were exponential. Based on these models, the spatial dependence of depth data was moderate to strong. The performance of interpolations was checked by cross-validation and its indices i.e. mean standardized prediction errors (MSPR), root mean square prediction errors (RMSPE), average kriging standard error (AKSE), and root mean square standardized prediction errors (RMSSPE) were assessed. A trend of depth increasing towards the northeast was observed at all of the interfaces.

Empirical relationships of shear wave velocity, SPT-N value and vertical effective stress for different soils in Mashhad, Iran

“…Other properties, including SPT-N value, soil texture, unit weight, natural moisture content, fine percent and Atterberg limits and groundwater table also were determined in the all boreholes. Properties of different types of soils are summarized in Table 1 by V s class which was based on previous studies of authors [Ghazi et al 2014]. Maximum values of N 60 and unit weight, and minimum values of moisture content are observed in gravely soils.…”

Extreme subsidence in a populated city (Mashhad) detected by PSInSAR considering groundwater withdrawal and geotechnical properties

“…Mashhad is located in the northern slopes of Binalood Mountains and Paleo-Tethys suture zone and is mostly laid on thick Quaternary deposits surrounded by Marls in northeastern margins, Ultramafic and Mafic and outcrops in the southern parts, and Phyllite and Slate in the western and southwestern. Furthermore, Kashafrood River passing through the northeast of the city has important effects on the depositional process of the fine-grained deposits and is the most significant geomorphic phenomenon of Mashhad watersheds 53 , 75 . Based on the previous reports 53 , 75 – 77 , sediment and alluvial fan deposits generally contain gravels and sands, extend over the south, southwest, and west parts of the city and alluvial plain deposits consist of clays and silts, cover center and eastern parts.…”

“…Furthermore, Kashafrood River passing through the northeast of the city has important effects on the depositional process of the fine-grained deposits and is the most significant geomorphic phenomenon of Mashhad watersheds 53,75 . Based on the previous reports 53, [75][76][77] , sediment and alluvial fan deposits generally contain gravels and sands, extend over the south, southwest, and west parts of the city and alluvial plain deposits consist of clays and silts, cover center and eastern parts. Figure 7 shows ground displacement rate along the A-A section (shown in Fig.…”

Geostatistical interpolation model selection based on ArcGIS and spatio-temporal variability analysis of groundwater level in piedmont plains, northwest China

“…The nugget to sill radio shall be between 0 and 1. When the nugget effect is <0.25, the considered strongly spatially dependent; the variable is considered moderately spatially dependent as the nugget effect is between 0.25 and 0.75, while the nugget effect is >0.75, the variable is considered weakly spatially dependent (Ghazi et al 2014 ). Analysis of spatial distribution pattern: based on the hydrogeological conditions and different land use, the spatial variability pattern of typical partitions in the piedmont plain are analyzed, the effect of human activities on spatial variability of groundwater level is also discussed.…”

“…The nugget to sill radio shall be between 0 and 1. When the nugget effect is <0.25, the considered strongly spatially dependent; the variable is considered moderately spatially dependent as the nugget effect is between 0.25 and 0.75, while the nugget effect is >0.75, the variable is considered weakly spatially dependent (Ghazi et al 2014 ).…”