V(S)30, site amplifications and some comparisons: The Adapazari (Turkey) case

The aim of this study was to investigate the role of V(S)30 in site amplifications in the Adapazari region, Turkey. To fulfil this aim, amplifications from V(S)30 measurements were compared with earthquake data for different soil types in the seismic design codes. The Adapazari area was selected as the study area, and shear-wave velocity distribution was obtained by the multichannel analysis of surface waves (MASWs) method at 100 sites for the top 50 m of soil. Aftershock data following the Mw 7.4 Izmit earthquake of 17 August 1999 gave magnitudes between 4.0 and 5.6 at six stations installed in and around the Adapazari Basin, at Babali, Seker, Genc, Hastane, Toyota and Imar. This data was used to estimate site amplifications by the reference-station method. In addition, the fundamental periods of the station sites were estimated by the single station method. Site classifications based on V(S)30 in the seismic design codes were compared with the fundamental periods and amplification values. It was found that site amplifications (from earthquake data) and relevant spectra (from V(S)30) are not in good agreement for soils in Adapazari (Turkey). (c) 2013 Elsevier Ltd. All rights reserved

TERRESTRIAL MAGNETISM IN THE OTTOMAN EMPIRE: DOCUMENTS AND MEASUREMENTS

Geophysics, in the modern sense, started with geomagnetic works in the 1600s in the Ottoman Empire. The period between 1600 and 1800 included the measurement of magnetic declination, inclination and magnetic field strength. Before that time, there was only a little information available, such as how to use a compass, for example in the Kitabi Bahriye (the Book of Navigation) by Piri Reis, one of the most important mariners of the Ottoman Empire. However, this may not mean that magnetic declination was generally understood. The first Turkish scientific book relating to terrestrial magnetism was the book Fuyuzat-i Miknatissiye that was translated in 1731 from German into Turkish by Ibrahim Muteferrika. The subject of that book was earth's magnetism. The magnetic compass was mentioned in several books including Muhammed al Awfi's Jami al-Hikayat (translated into Turkish by Ibn Arabsah); Piri Reis's Kitab-I Bahriye (The Book of ` Navigation'); Seydi Ali Reis's Risale-i Mirat-I Kainat min Alat-I Irtifa (The Treatise called the Mirror of Universe according to the instrument for measuring Altitude) and Kitab Al-Muhit Fi. Ilm'al-Eflak Va'l Abhur (Book of the Regional Seas and the Science of Astronomy and Navigation). There were two original magnetic declination measurements made by Ottoman Turks in Istanbul in 1727 and 1893. Also, many geomagnetic measurements were carried out during international campaigns between 1600 and 1917 that visited Ottoman territory

SoilEngineering: A Microsoft Excel (R) spreadsheet (c) program for geotechnical and geophysical analysis of soils

SoilEngineering is a user-friendly, interactive Microsoft Excel (R) spreadsheet program for the geotechnical and geophysical analysis of soils. The influence of soil behavior on earthquake characteristics and/or structural design is one of the major elements in investigating earthquake forces, and thus the structural response with static and dynamic loads. With its interactive nature, the program provides the user with an opportunity to undertake soil static and dynamic load analysis. The program is formed by three main options: (1) Data Preparation, (2) Derived Parameters and (3) Analysis of Soil Problems (with Static and Dynamic Loads). The Data Preparation option is divided into four modules: Seismic Refraction Data, Geoelectrical Data, Borehole and SPT (N) Data and Laboratory Data. The Derived Parameters option is divided into two modules: Geotechnical Parameters Derived from Geophysical Data and Relationships between Vs and SPT (N) Values. The Analysis of Soil Problems (with Static and Dynamic Loads) option is divided into nine modules: Bearing Capacity for Shallow and Deep Foundations. Settlement Analysis (Static and Dynamic Loads), Estimation of Subgrade Reaction Coefficient, Slope Stability Analysis, Seismic Hazard Analysis, Strong Motion Attenuation Relationships, Acceleration/Velocity/Displacement Spectra, Soil Amplification Analysis and Soil Liquefaction Analysis. Soil engineering also permits plotting geophysical and geotechnical data with analysis. (C) 2010 Elsevier Ltd. All rights reserved

Fast and efficient use of geophysical and geotechnical data in urban microzonation studies at small scales: Using Sisli/Istanbul (Turkey) as example

The main purpose of this study is to provide the combined use of geophysical and geotechnical data in context of microzonation. Earthquake occurrences on the North Anatolian Fault, being usually characterized and well documented in history, a time dependent model can be reasonably used for the probabilistic assessment of the seismic hazard in Istanbul. 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 (30%) in a given time period (30 years). By using deterministic seismic hazard analysis, the magnitudes were estimated by the four rapture (with four different fault length, 108, 119 and 174 km) model of North Anatolian Fault Zone in Marmara Region. By using both analyses (deterministic and probabilistic), magnitude of design earthquake was taken as 7.6. From this design earthquake, accelerations were estimated for several distances (from 15 to 50 km) by several attenuation relations. In the second phase of the study, soil amplification factors and site characteristic periods were determined and estimated by seismic measurements and Standard Penetration Test (SPT test) data for the area of Sisli where the important part of Istanbul city is located. Geotechnical test data from boreholes and laboratory measurements were evaluated with geophysical data. Soil amplification values estimated by empirical relationships in terms of shear wave velocities are in the range of 1.0 and 2.1 values. Shear wave velocity (Vs, 30) values are 381.5 and 915 (m/s). Site characteristic period range is between 0.2 and 0.5 s

A Comparative Soil Liquefaction Analysis with a MATLAB (R) based Algorithm: soiLique

Soil liquefaction is one of the ground failures induced by earthquakes. Determining the safety factor and the settlements are the most common analyses to decrease liquefaction-induced failures and hazards. Scientists have suggested numerous empirical formulas to detect and mitigate liquefaction-based hazards, and they have been used over the decades. This study aims to present a user-friendly and interactive program for deterministic soil liquefaction analyses. The algorithm presented in this study, soiLique, is the first MATLAB (R) program, including a graphical user interface that provides the deterministic liquefaction analysis with the computation of parameters propounded with the formulas. One of the advantages of soiLique is that it allows picking the physical property of every layer (i.e., fine or coarse), which provides dealing with liquefaction prone layer(s) directly when necessary. Not only can one calculate parameters regarding soil liquefaction with the help of this program, but one also can see graphically supported results. The robustness of soiLique is checked with another soil liquefaction analysis program, SoilEngineering, which was introduced by Ozcep (2010). Calculations were done separately using real SPT data and synthetic data such as V-s measurements and CPT data. The real SPT data and synthetic VS data were used to compare soiLique and SoilEngineering (Ozcep, 2010). The present study presents an example of CPT data analysis but could not be used for comparison. Comparisons reveal that outputs of soiLique and results of SoilEngineering showed a good agreement

Variations of soil liquefaction safety factors depending on several design earthquakes in the city of Yalova (Turkey)

The 1999 earthquakes (which had magnitudes Mw of 7.4 and 7.2) in Turkey caused great destruction and damage for Yalova (Turkey) sites in the Marmara Region. In the investigation area, the mainly reason for destruction is the liquefaction. As it is known, liquefaction occurs in saturated soils, that is, soils in which the space between individual particles is completely filled with water. In the frame of this research, probabilistic and deterministic analyses were used to determine the safety factors for several parameters. For the study area, the probabilistic seismic hazard analysis showed very high seismic activity. By using deterministic seismic hazard analysis, the magnitudes were estimated for the three rupture (with four different fault lengths, 109, 120 and 174 km) model of North Anatolian Fault Zone in the Marmara Region. By using analysis (deterministic and probabilistic), estimated magnitudes and accelerations of earthquake were taken as alternatively 6.5, 7.0 and 7.5 for magnitudes and from 0.2 - 0.50 g for accelerations. For several design earthquake parameters, cyclic stress analysis of liquefaction were applied to the field data (both SPT (N) and S wave data), obtained in the Yalova region. In the first phase of the study of liquefaction, the cyclic stress ratio approach was applied for all data to analysis of soil liquefaction. Then FS (factor of safety) values of liquefaction were estimated with this approach