A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Site characterization in Ismailia, Egypt using seismic ambient vibration array
Abstract Seismic ambient vibration array measurements were carried out at seven sites in Ismailia, Egypt in order to obtain one-dimensional (1D) shear wave velocity (Vs) profiles and horizontal-to-vertical spectral ratios (HVSR). We applied the spatial autocorrelation (SPAC) method to the ambient vibration data for the estimating Rayleigh-wave dispersion curves and obtained 1D Vs profiles. The deeper parts (90–350 m) of the estimated models have Vs values ranging between 500 and 700 m/s, while the subsurface parts have Vs varying between 140 and 200 m/s. The averaged Vs in the upper 30 m based on the results indicate that site classes of all the sites are classified as C or D according to NEHRP soil classification. The computed site amplification factors derived from the estimated Vs profiles show that the resonant frequencies at sites on the east side of the Suez Canal are below 1 Hz, while those at sites on the west side vary between 1 and 2 Hz, indicating the difference of subsurface geology across the Suez Canal. The HVSR curves at each site are generally similar for all sensors, indicating nearly flat subsurface layers beneath each site. We also compared the dominant frequencies of HVSRs and those derived from 1D amplification factors. The comparisons show that both the frequencies are similar to each other, but there are slight differences possibly due to the lack of deeper sedimentary layer structures and lower resolution of HVSRs in the lower frequency range, indicating the importance of further ambient vibration survey with broadband sensors. The results show that the combination of SPAC and HVSR methods is advantageous to estimate proper Vs profiles to evaluate site effects for earthquake disaster mitigation.
Highlights Seismic ambient vibration array measurements were conducted at seven sites in Ismailia city, Egypt in order to obtain Vs profiles and calculate the HVSR. The Spatial Autocorrelation (SPAC) method was applied to the array data to estimate Vs profiles after inversion of the Rayleigh waves dispersion curves. Depending on the results of the Vs profiles, the engineering bedrock with Vs of 400–600 m/s was detected for all the sites at different depths (3–32 m). Based on the AVS30 results, all sites are categorized into site class C or D. According to the site amplification factor, the resonant frequencies for the sites located on the west side of the Suez Canal were in the frequency range 1–2 Hz. For the sites situated on the east side of the Suez Canal, the resonant frequencies were lower than 1 Hz. We compared the dominant frequencies of HVSR peaks and those derived from 1D amplification factors, they show a linear relationship indicating fairly acceptable obtained Vs profiles for all the sites. We concluded that, the SPAC technique gives a proper estimation of the Vs profile to evaluate the site effects for earthquake disaster mitigation.
Site characterization in Ismailia, Egypt using seismic ambient vibration array
Abstract Seismic ambient vibration array measurements were carried out at seven sites in Ismailia, Egypt in order to obtain one-dimensional (1D) shear wave velocity (Vs) profiles and horizontal-to-vertical spectral ratios (HVSR). We applied the spatial autocorrelation (SPAC) method to the ambient vibration data for the estimating Rayleigh-wave dispersion curves and obtained 1D Vs profiles. The deeper parts (90–350 m) of the estimated models have Vs values ranging between 500 and 700 m/s, while the subsurface parts have Vs varying between 140 and 200 m/s. The averaged Vs in the upper 30 m based on the results indicate that site classes of all the sites are classified as C or D according to NEHRP soil classification. The computed site amplification factors derived from the estimated Vs profiles show that the resonant frequencies at sites on the east side of the Suez Canal are below 1 Hz, while those at sites on the west side vary between 1 and 2 Hz, indicating the difference of subsurface geology across the Suez Canal. The HVSR curves at each site are generally similar for all sensors, indicating nearly flat subsurface layers beneath each site. We also compared the dominant frequencies of HVSRs and those derived from 1D amplification factors. The comparisons show that both the frequencies are similar to each other, but there are slight differences possibly due to the lack of deeper sedimentary layer structures and lower resolution of HVSRs in the lower frequency range, indicating the importance of further ambient vibration survey with broadband sensors. The results show that the combination of SPAC and HVSR methods is advantageous to estimate proper Vs profiles to evaluate site effects for earthquake disaster mitigation.
Highlights Seismic ambient vibration array measurements were conducted at seven sites in Ismailia city, Egypt in order to obtain Vs profiles and calculate the HVSR. The Spatial Autocorrelation (SPAC) method was applied to the array data to estimate Vs profiles after inversion of the Rayleigh waves dispersion curves. Depending on the results of the Vs profiles, the engineering bedrock with Vs of 400–600 m/s was detected for all the sites at different depths (3–32 m). Based on the AVS30 results, all sites are categorized into site class C or D. According to the site amplification factor, the resonant frequencies for the sites located on the west side of the Suez Canal were in the frequency range 1–2 Hz. For the sites situated on the east side of the Suez Canal, the resonant frequencies were lower than 1 Hz. We compared the dominant frequencies of HVSR peaks and those derived from 1D amplification factors, they show a linear relationship indicating fairly acceptable obtained Vs profiles for all the sites. We concluded that, the SPAC technique gives a proper estimation of the Vs profile to evaluate the site effects for earthquake disaster mitigation.
Site characterization in Ismailia, Egypt using seismic ambient vibration array
Maklad, Mohamed (author) / Yokoi, Toshiaki (author) / Hayashida, Takumi (author) / ElGabry, Mohamed N. (author) / Hassan, Hany M. (author) / Hussein, H.M. (author) / Fattah, Tharwat A. (author) / Rashed, Mohamed (author)
Engineering Geology ; 279
2020-10-19
Article (Journal)
Electronic Resource
English
Implementing the new urban agenda : the case of Ismailia, Egypt
| Online Contents | 1996
International Water Technology Conference 2019 : 22nd IWTC : Ismailia - Egypt, 12-13 September 2019
| TIBKAT | 2019
Static and dynamic properties of cohesionless soil – new Suez canal area – Ismailia – Egypt
| Taylor & Francis Verlag | 2021