Although time-averaged shear wave velocity to the depth of 30 m(Vs30) is an important indicator of earthquake site effects, it is difficult to obtain. Several proxies have been used either individually or in combinati...Although time-averaged shear wave velocity to the depth of 30 m(Vs30) is an important indicator of earthquake site effects, it is difficult to obtain. Several proxies have been used either individually or in combination to infer Vs30 values during seismic hazard estimation under limited observational conditions. Sichuan Province is an area highly prone to earthquakes. Complex geological structures and lack of drilling sites mean that it is particularly important to establish a suitable approach for the estimation of Vs30 values for site classification. This study compared the application of three proxy-based approaches—geology-based, topographic slope-based, and terrain-based—to the estimation of Vs30 values in Sichuan Province. The results revealed that the residual between the measured logVs30 values and the estimations derived from the terrain-based approach was smallest, indicating best predictability. Stability analysis of the three approaches also showed that the terrain-based approach performed best. However, its performance in the plain area was poor,that is, the Vs30 values were mostly underestimated. This might indicate that the old strata, hard rock, and alluvial deposits formed by Quaternary glacier sediments were not identified appropriately in the plain area, highlighting the need for localized corrections.展开更多
Regional characterization of soil properties requires not only geostatistical models considering the spatial variability of soil properties but also methods that account for various sources of heterogeneous informatio...Regional characterization of soil properties requires not only geostatistical models considering the spatial variability of soil properties but also methods that account for various sources of heterogeneous information.This paper presents a multi-conditional random field approach to characterize the regional characteristics of the average shear-wave velocity in the top 30 meters of subsoil(vs30)based on hybrid geotechnical and geological data.The workflow for integrating multiple sources of soil properties information in a random field model for regional vs30 mapping is developed.A detailed two-dimensional(2D)synthetic digital soil field is generated to assess and verify this workflow.With the generated synthetic field,parametric studies on the investigation plans,the value of Markov Bayes coefficient B,element size,and a predefined grid of secondary data are performed.Practice on whether to incorporate secondary data for vs30 mapping and the determination of coefficient B are provided.展开更多
This study aimed to investigate the site characterization of the Senirkent Basin(Isparta)by using the microtremor(H/V)and surface wave analysis(ReMi)methods.Senirkent district,which is located on the foothill of the K...This study aimed to investigate the site characterization of the Senirkent Basin(Isparta)by using the microtremor(H/V)and surface wave analysis(ReMi)methods.Senirkent district,which is located on the foothill of the Kap?Mountain,are prone to seismic and landslide hazards.After the last landslip disaster(1995),the city has continued to develop on the alluvial basin.The microtremor data collected at 41 stations were analyzed.The predominant frequency and the amplification of the soil were found to be in the range of 1.8–6.6 Hz and 0.8–6.8,respectively.These are 4.0-6.8 Hz and 1-2.5 around the slope of the Kap?Mountain and 0.8-3.6 Hz and 3.0-6.6 at alluvium deposits of the valley.The ReMi data collected along 41 profiles were analyzed to obtain a Vs30 map.The soil classifications were done by using Vs30 values according to NEHRP soil classification criteria.The results showed that the southern area of the study had better soil conditions with Vs30 between 360-1160 m/s and soil class between C and B.The alluvium deposits on the north are relatively low with Vs30 in the range of 260-360 m/s and soil class D.展开更多
Understanding the parameters of PGA （peak ground acceleration） is very important for seismic hazard mitigation and environmental planning in Mandalay City, Myanmar. In this study, fifty SPTs （Standard Penetration T...Understanding the parameters of PGA （peak ground acceleration） is very important for seismic hazard mitigation and environmental planning in Mandalay City, Myanmar. In this study, fifty SPTs （Standard Penetration Tests） measurement data were collected in Mandalay City, for calculating average shear velocity Vs30, which will be used in seismic microzonation mapping. The shear wave velocity Vs30 of the top layer is Vs30 〈 220 m/s. The ground motion characteristic was estimated by means of the predominant periods and linear magnification factors obtained using the multiple reflection analysis. The highest potential zone of seismic hazard mostly locates the north western marginal part of Mandalay city, in the proximal portion to the dextral Sagaing fault.展开更多
基金financially supported by the National Key Research and Development Program of China (Grant No. 2018YFC1509003)the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA20060402).
文摘Although time-averaged shear wave velocity to the depth of 30 m(Vs30) is an important indicator of earthquake site effects, it is difficult to obtain. Several proxies have been used either individually or in combination to infer Vs30 values during seismic hazard estimation under limited observational conditions. Sichuan Province is an area highly prone to earthquakes. Complex geological structures and lack of drilling sites mean that it is particularly important to establish a suitable approach for the estimation of Vs30 values for site classification. This study compared the application of three proxy-based approaches—geology-based, topographic slope-based, and terrain-based—to the estimation of Vs30 values in Sichuan Province. The results revealed that the residual between the measured logVs30 values and the estimations derived from the terrain-based approach was smallest, indicating best predictability. Stability analysis of the three approaches also showed that the terrain-based approach performed best. However, its performance in the plain area was poor,that is, the Vs30 values were mostly underestimated. This might indicate that the old strata, hard rock, and alluvial deposits formed by Quaternary glacier sediments were not identified appropriately in the plain area, highlighting the need for localized corrections.
基金supported by the National Natural Science Foundation of China(Grant No.5210082052)the Zhejiang Provincial Natural Science Foundation,China(Grant No.LQ22E080028)the Science Foundation of Zhejiang Sci-Tech University,China(Grant No.19052459-Y).
文摘Regional characterization of soil properties requires not only geostatistical models considering the spatial variability of soil properties but also methods that account for various sources of heterogeneous information.This paper presents a multi-conditional random field approach to characterize the regional characteristics of the average shear-wave velocity in the top 30 meters of subsoil(vs30)based on hybrid geotechnical and geological data.The workflow for integrating multiple sources of soil properties information in a random field model for regional vs30 mapping is developed.A detailed two-dimensional(2D)synthetic digital soil field is generated to assess and verify this workflow.With the generated synthetic field,parametric studies on the investigation plans,the value of Markov Bayes coefficient B,element size,and a predefined grid of secondary data are performed.Practice on whether to incorporate secondary data for vs30 mapping and the determination of coefficient B are provided.
文摘This study aimed to investigate the site characterization of the Senirkent Basin(Isparta)by using the microtremor(H/V)and surface wave analysis(ReMi)methods.Senirkent district,which is located on the foothill of the Kap?Mountain,are prone to seismic and landslide hazards.After the last landslip disaster(1995),the city has continued to develop on the alluvial basin.The microtremor data collected at 41 stations were analyzed.The predominant frequency and the amplification of the soil were found to be in the range of 1.8–6.6 Hz and 0.8–6.8,respectively.These are 4.0-6.8 Hz and 1-2.5 around the slope of the Kap?Mountain and 0.8-3.6 Hz and 3.0-6.6 at alluvium deposits of the valley.The ReMi data collected along 41 profiles were analyzed to obtain a Vs30 map.The soil classifications were done by using Vs30 values according to NEHRP soil classification criteria.The results showed that the southern area of the study had better soil conditions with Vs30 between 360-1160 m/s and soil class between C and B.The alluvium deposits on the north are relatively low with Vs30 in the range of 260-360 m/s and soil class D.
文摘Understanding the parameters of PGA （peak ground acceleration） is very important for seismic hazard mitigation and environmental planning in Mandalay City, Myanmar. In this study, fifty SPTs （Standard Penetration Tests） measurement data were collected in Mandalay City, for calculating average shear velocity Vs30, which will be used in seismic microzonation mapping. The shear wave velocity Vs30 of the top layer is Vs30 〈 220 m/s. The ground motion characteristic was estimated by means of the predominant periods and linear magnification factors obtained using the multiple reflection analysis. The highest potential zone of seismic hazard mostly locates the north western marginal part of Mandalay city, in the proximal portion to the dextral Sagaing fault.
