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Main purpose of this study is to provide an application of seismic microzonation at small scales. For the study area, the probabilistic seismic hazard analysis was determined by using Poisson probabilistic approaches. The hazard gives the probability that a given level of acceleration will be exceeded (%15) in a given time period (50 years). By usi...
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... velocity (Vs) is an important parameter for evaluating dynamic behavior of soil for engineering and microzonation purposes. Vs averaged over the top 30 m of soil are referred to as Vs30. Both the NEHRP Provi- sions and the Uniform Building Code use Vs30 to classify sites according to type of soil for earthquake engineering design. As it is known, shear wave velocity is an index property to evaluate the soil amplifications. In Table 3a, it was given the shear wave and soil amplification relations according to Midorikawa (1984). Study area is divided in to two sub-regions: A and B regions as shown in Figure 3. To estimate the soil amplifications for two zones, seismic refraction measurements were taken to obtain the shear wave velocities. Figures 4a and b show Vs30 values on map for A and B Regions. Figures 5a and b shows characteristic site period values on map for A and B regions. Finally, figures 6a and b shows soil amplification values on map for A and B regions according ...
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The main target of the present study is to investigate the foundation layers and the subsurface structures in an Egyptian solar plant site using geophysical techniques including the seismic refraction and Multichannel Analysis of Surface Waves (MASW). The studied solar park is situated at about 40 km to the north of Aswan city on the Aswan-Cairo hi...
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... Since the 1970s, following lessons learned from earthquakes and regarding site effects, seismic microzonation has been recognised as the most accepted tool in seismic hazard assessment and risk mitigation. Many important regional or local microzonation studies have therefore been carried out all over the world in the last 20 years ( [1][2][3][4][5][6][7][8][9]). ...
This paper presents a seismic microzonation study performed in an area of the Northern Apennines (Italy) in order to reduce the level of risk from landslide hazard, to support decisions in urban planning and to provide useful information for building design. The area in question measures about 2.6 km2 and is characterised by considerable landslide susceptibility also in non seismic conditions as evidenced by a number of surveys carried out over the past years. The slope deposit, lying over a marley-arenaceous formation, shows a variable thickness from a few metres to 30 m and consists of fine silty-clay, clay-sandy and silty-sandy soil in a variable amount. Quiescent and active landslide areas with ground movements involving the shallowest layers of the soil deposit have been detected.
... For this region, İmre et al. 3 prepared a micro-scale microzonation map. Using the same approach, several studies have been carried out [4][5][6][7][8][9][10][11][12] . A microzonation map has been prepared for the region using determined threshold shear wave velocity values following Ansal 13 . ...
Multi-channel analysis of surface waves (MASW) and micrometer array measurements (MAM) have been carried out in the flood-prone areas of Selimpaşa, Kavakli, Ortakoy and Kadikoy in Turkey to understand several soil problems, especially soil amplification during earthquakes. In the region, there are now more than 80 geotechnical boreholes with SPT and laboratory test data, as also MASW–MAM geophysi-cal measurements at more than 100 locations. All these data have been evaluated to classify the soils according to Eurocode 8, determine soil amplification and finally to obtain a microzonation map. According to the Eurocode soil classification system, there are D, B and C type soils in the area of study. In the final microzonation map, the study area is divided into three sub-regions based on shear wave (Vs) velocities – sub-region A (Vs velocities higher than 420 m/s), sub-region B (Vs velocities between 360 and 420 m/s) and sub-region C (Vs velocities lower than 360 m/s). Results show that there are clear relationships between Vs 30 and flood damage effect. Vs 30: 180 m/s is characteristic of zone with D type soil, which is transported alluvial soil. Vs 30 < 180 zones define the limits of the areas affected by floods in the study region.
... For this region, İmre et al. 3 prepared a micro-scale microzonation map. Using the same approach, several studies have been carried out [4][5][6][7][8][9][10][11][12] . A microzonation map has been prepared for the region using determined threshold shear wave velocity values following Ansal 13 . ...
Multi-channel analysis of surface waves (MASW) and micrometer array measurements (MAM) have been carried out in the flood-prone areas of Selimpasa, Kavakli, Ortakoy and Kadikoy in Turkey to understand several soil problems, especially soil amplification during earthquakes. In the region, there are now more than 80 geotechnical boreholes with SPT and laboratory test data, as also MASW-MAM geophysical measurements at more than 100 locations. All these data have been evaluated to classify the soils according to Eurocode 8, determine soil amplification and finally to obtain a microzonation map. According to the Eurocode soil classification system, there are D, B and C type soils in the area of study. In the final microzonation map, the study area is divided into three sub-regions based on shear wave (Vs) velocities - sub-region A (Vs velocities higher than 420 m/s), sub-region B (Vs velocities between 360 and 420 m/s) and sub-region C (Vs velocities lower than 360 m/s). Results show that there are clear relationships between Vs 30 and flood damage effect. Vs 30: 180 m/s is characteristic of zone with D type soil, which is transported alluvial soil. Vs 30 < 180 zones define the limits of the areas affected by floods in the study region.
... By using both forward and inverse solutions algorithm, S wave velocities were calculated and drawn, depending on the distance. In Table 5, MASW and MAM results on A and B region (Ozcep et al., 2010d). ...
... Seismic microzonation map for A region(Ozcep et al., 2010d). ...
... Seismic microzonation map for B region(Ozcep et al., 2010d). ...
The aim of this study is to review the geophysical investigations in civil engineering and urban planning by some case histories in Turkey. Geophysics deals with a wide array of earth phenomena, including the temperature distribution of the earth's interior (the source, configuration and variations of the geomagnetic field) and the large-scale features of the terrestrial crust, such as rifts, continental sutures and mid-oceanic ridges. From the geophysical point of view, civil engineering and urban planning includes several geophysical topics used to investigate the physical properties, the physical techniques for regional and local land use planning or micro-zonation, the natural disaster risk estimation studies, etc. In this study, the geophysical approach, regarding civil engineering and urban planning against the natural or artificial disaster risk in macro (human/nature) and micro (society/earth) scales, is given. Geophysical methods provide solutions to a wide range of geotechnical problems: Slope stability, soil liquefaction and amplification studies, site investigations and testing, water works, subways, etc. In this study, an evaluation of the geophysical methods applied to geotechnical problems related to the soils is presented. Soils consist of the products of physical and chemical weathering of the rocks of the earth's crust. As a part of the engineering design, the aim of a site/soil investigation is to provide the basic data to evaluate the interaction of the natural environment with the proposed structure. As it is known, using physical measurements in geophysics, it is studied as the natural and artificially generated physical fields of the earth.
Muğla Milas ilçesinde Söke Milas Karayolu Derince Çayı köprüsünün 3,5 km kuzeyinde Derince Çayı üzerinde yer alan Derince Barajı, önyüzü beton kaplı kum çakıl dolgu tipinde olup temelden yüksekliği 67 m’dir. Baraj 2014 yılında hizmete açılmış olup, 2015 yılında barajın deprem altındaki yapısal durum ve performansını izlemek üzere bir adet gövde üzerine bir adet ana kayaya olmak üzere 2 adet ivmeölçer cihazı yerleştirilmiştir. Bu istasyonlar ile bir deprem anında barajın depremlere karşı vermiş olduğu tepki gözlenmiş olacaktır. 2017-2018 yıllarında Ege bölgesinde meydana gelen depremlerden anakaya ve baraj gövdesinde kurulu bulunan ivmeölçerler tarafından kaydedilen; lokasyonları farklı Mw>4.4 olan 9 adet deprem kaydı kullanılmıştır. Barajın dinamik özelliklerinin belirlemek amacıyla kaydedilen deprem sinyallerine referans yöntemine göre standart spektral oran (SSR) ve yatay/düşey spektral oran (HVSR) yöntemleri uygulanmıştır. Bu iki yöntemin analizleri sonucunda baraj gövdesine ait büyütmeler, baskın frekanslar belirlenmiştir. Bu yöntemin analizi sonucunda barajın hakim frekansı 2.36 Hz bulunmuş ve iki yöntem karşılaştırılmıştır.
The purpose of this study is to examine the risk of seismic hazard arising from local ground characteristics of Antakya by using probabilistic methods associated with the circumstances based on Geographical Information Systems (GIS) within the framework of micro zonation technique. In this regard, local ground parameters such as geological, topographic and hydrogeological properties and effective factors like lithology and distance from fault lines, geomorphology and slope, underground water and distance from river system which have effects on seismic hazard risk were determined and mapped. Then, sensitivity classification between these factors which contributed to identification of codomains and creation of grid maps with 10 m resolution was implemented. During this process, conditional weights analysis method was used. Map of seismic hazard risk belonging to urban land was generated by combining all of the grid maps according to their degree of influence. This map contains 5 different seismic hazard risk classes determined in terms of effective factors which may emerge in the future depending on the local ground characteristics. Moreover, their footprints and alignments were explained by a geographical viewpoint.
This study is presented as a contribution to earthquake disaster mitigation studies for selected cities in Turkey. The risk evaluations must be based on earthquake hazard analysis and city information. To estimate the ground motion level, data for earthquakes with a magnitude greater than 4.5 and an epicenter location within a 100-km radius of each city were used for the period from 1900 to 2006, as recorded at the Kandilli Observatory and Earthquake Research Institute. Probabilistic seismic hazard analysis for each city was carried out using Poisson probabilistic approaches. Ground motion level was estimated as the probability of a given degree of acceleration with a 10% exceedence rate during a 50-year time period for each city. The risk level of each city was evaluated using the number of houses, the per-capita income of city residents, population, and ground motion levels. The maximum risk level obtained for the cities was taken as a reference value for relative risk assessment, and other risk values were estimated relative to the maximum risk level. When the selected cities were classified according to their relative risk levels, the five most risky cities were found to be, in descending order of risk, Istanbul, Izmir, Ankara, Bursa, and Kocaeli.
