Source and Site Factors in Microzonation

Ansal, Atilla; Tönük, Gökçe

doi:10.1007/978-1-4020-5893-6_4

Cited by 36 publications

(17 citation statements)

References 10 publications

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“…The lab testing methods are complex and lead to difficulties associated with sample disturbance during sampling and testing. The empirical stress based SPT-N approach has gained a wide acceptance in geotechnical engineering communities [68]. Cyclic stress ratio (CSR)…”

Section: Spt Based Liquefaction Potential Assessmentmentioning

confidence: 99%

Land Damage Mapping and Liquefaction Potential Analysis of Soils from the Epicentral Region of 2017 Pohang Mw 5.4 Earthquake, South Korea

et al. 2020

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Studies on earthquake-induced liquefaction and identification of source unit for causing liquefaction have been a major concern in sustainable land use development especially in low to moderate seismic areas. During the 2017 M w 5.4 Pohang earthquake, widespread liquefaction was reported around the Heunghae basin, which was the first ever reported case of liquefaction in the modern seismic history of Korea. The epicentral area is one of the major industrial hubs along the SE Korean Peninsula with no detailed liquefaction hazard map. The purpose of this study was to determine the land damage classification on the basis of surface manifestation of liquefaction features and carry out detailed liquefaction potential analysis to delineate the depth of liquefiable soil. This will eventually support developing a liquefaction hazard zonation map and sustainable development of infrastructure to minimize earthquake damages. In this present study, the southern part of the Heunghae basin, which has more field evidences of liquefaction than the northern part, was taken for detailed liquefaction analysis. From the detailed analysis, it was observed that the soils from 1.5 to 15 m depth with the probability of liquefaction varying from 2 to 20 are prone to liquefaction. On the basis of land damage pattern, the epicentral area falls in orange to red zone, which means the necessity of further detailed liquefaction analysis. This study urges more detailed liquefaction zonation should be carried out for the epicentral area and liquefaction hazard should be included in the multi-hazard map in the future for the sustainable land use planning.

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Section: Spt Based Liquefaction Potential Assessmentmentioning

confidence: 99%

Land Damage Mapping and Liquefaction Potential Analysis of Soils from the Epicentral Region of 2017 Pohang Mw 5.4 Earthquake, South Korea

et al. 2020

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“…In particular, the applied criteria for the selection of the ground motion data were (1) the event should have been triggered by normal causative faults, (2) the earthquake magnitude ranged between 5.5 \ M \ 6.6 and (3) the ground motion should be recorded in rock outcrops conditions. In this study, only the input acceleration time histories have been chosen for scaling since they appeared more suitable for microzonation studies (Ansal and Tönük 2007). The scaling was based on the value of the design acceleration of Greek Seismic Code and the scaled time histories were used as input motion in order to estimate the value of acceleration on ground surface for each one of the seven site.…”

Section: Evaluating Earthquake Characteristics On the Ground Surfacementioning

confidence: 99%

Liquefaction hazard mapping at the town of Edessa, Northern Greece

Papathanassiou

Valkaniotis

2009

Nat Hazards

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The town of Edessa is located on Northern Greece at a region that is characterized as low seismicity zone due to the fact that few moderate events of M \ 6 occurred during the last century. According to the Greek Seismic Code, the expected acceleration having a 10% probability of being exceeded in 50 years is equal to 0.16g. However, an amplification of ground motion is likely to occur due the local geology that is consisted of Holocene fluvio-torrential deposits. The basic aim of this paper is to evaluate the site amplification due to geological conditions and to assess the liquefaction hazard. In order to achieve this, 1-D site response analyses were performed. The data that were employed for the construction of the numerical models have been collected from borings with standard penetrations tests (SPT) that were drilled for construction purposes. Afterward, the liquefaction potential of the subsoil layers was evaluated taking into consideration two seismic scenarios. The first scenario was based on the seismic parameters, earthquake magnitude and PGA, assigned by the Greek Seismic Code. On the second seismic model, we employed the values of acceleration, resulted from the 1-D analyses and the earthquake magnitude as it was defined by the Greek Seismic Code. In order to compile the liquefaction hazard maps, we initially estimated the liquefaction potential index (LPI) of the soil columns using the parameters provided by SPT, for both seismic loadings, and afterward we correlated these values with the proposed classification of the severity of liquefactioninduced deformations. In addition, having computed the value of probability based on the LPI, liquefaction manifestations probability maps were compiled for both scenarios. The result of this study was that liquefaction-induced ground disruptions are likely to occur at the center of the city, among the branches of Voda River, only when the amplified values of acceleration are taken into account to the computation of liquefaction potential.

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“…However, the use of laboratory testing is complicated due to difficulties associated with sample disturbance during both sampling and reconsolidation. Thus, empirical approaches based on the in-situ penetration test results have gained popularity in engineering practice as well as in engineering codes (Ansal and Tönük, 2007).…”

Section: Assessment Of Liquefaction Potentialmentioning

confidence: 99%

“…The more comprehensive alternative is to calculate the average shear stress with depth using site response analyses depending on the soil stratification and stiffness of the soil layers (Ansal and Tönük, 2007). CRR expresses the capacity of the soil to resist liquefaction.…”

Section: Assessment Of Liquefaction Potentialmentioning

confidence: 99%

“…This approach evolved over the time (Seed, 1979;Seed and Idriss, 1982;Seed et al, 1985;NCEER, 1997;Youd et al, 2001;Cetin et al, 2004;Idriss and Boulanger, 2006). In the literature, liquefaction assessments of different regions are available (e.g., Chu et al, 2004;Seyrek, 2003;Ansal and Tönük, 2007;Novikova et al, 2007;Mhaske and Choudhury, 2010).…”

Section: Introductionmentioning

confidence: 99%

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Soil liquefaction potential in Eskişehir, NW Turkey

Tosun

Seyrek

Orhan

et al. 2011

Nat. Hazards Earth Syst. Sci.

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Abstract. Liquefaction is one of the critical problems in geotechnical engineering. High ground water levels and alluvial soils have a high potential risk for damage due to liquefaction, especially in seismically active regions. Eskişehir urban area, studied in this article, is situated within the second degree earthquake region on the seismic hazard zonation map of Turkey and is surrounded by Eskişehir, North Anatolian, Kütahya and Simav Fault Zones. Geotechnical investigations are carried out in two stages: field and laboratory. In the first stage, 232 boreholes in different locations were drilled and Standard Penetration Test (SPT) was performed. Test pits at 106 different locations were also excavated to support geotechnical data obtained from field tests. In the second stage, experimental studies were performed to determine the Atterberg limits and physical properties of soils. Liquefaction potential was investigated by a simplified method based on SPT. A scenario earthquake of magnitude M = 6.4, produced by Eskişehir Fault Zone, was used in the calculations. Analyses were carried out for PGA levels at 0.19, 0.30 and 0.47 g. The results of the analyses indicate that presence of high ground water level and alluvial soil increase the liquefaction potential with the seismic features of the region. Following the analyses, liquefaction potential maps were produced for different depth intervals and can be used effectively for development plans and risk management practices in Eskişehir.

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Source and Site Factors in Microzonation

Cited by 36 publications

References 10 publications

Land Damage Mapping and Liquefaction Potential Analysis of Soils from the Epicentral Region of 2017 Pohang Mw 5.4 Earthquake, South Korea

Land Damage Mapping and Liquefaction Potential Analysis of Soils from the Epicentral Region of 2017 Pohang Mw 5.4 Earthquake, South Korea

Liquefaction hazard mapping at the town of Edessa, Northern Greece

Soil liquefaction potential in Eskişehir, NW Turkey

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