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11.
Matteo Picozzi Angelo Strollo Stefano Parolai Eser Durukal Oguz Özel Savas Karabulut Jochen Zschau Mustafa Erdik 《Soil Dynamics and Earthquake Engineering》2009
Single station seismic noise measurements were carried out at 192 sites in the western part of Istanbul, Turkey. This extensive survey allowed the fundamental resonance frequency of the sedimentary cover to be mapped, and identify areas prone to site amplification. The results are in good agreement with the geological distribution of sedimentary units, indicating a progressive decrease of the fundamental resonance frequencies from the northeastern part, where the bedrock outcrops, towards the southwestern side, where a thickness of some hundreds meters for the sedimentary cover is estimated. The particular distribution of fundamental resonance frequencies indicates that local amplification of the ground motion might play a significative role in explaining the anomalous damage distribution after the 17 August 1999 Kocaeli Earthquake. 相似文献
12.
P. Breen L.A. Robinson S.I. Rogers A.M. Knights G. Piet T. Churilova P. Margonski N. Papadopoulou E. Akoglu A. Eriksson Z. Finenko V. Fleming-Lehtinen B. Galil F. Goodsir M. Goren O. Kryvenko J.M. Leppanen V. Markantonatou S. Moncheva T. Oguz L. Paltriguera K. Stefanova F. Timofte F. Thomsen 《Marine Policy》2012
13.
Natural Hazards - Drought is considered to be one of the most devastating natural disasters. In recent years, determination of historical droughts has gained more importance. This can be attributed... 相似文献
14.
Conditional simulation of USLE/RUSLE soil erodibility factor by geostatistics in a Mediterranean Catchment,Turkey 总被引：4，自引：4，他引：0
Oguz Baskan Hicrettin Cebel Suat Akgul Gunay Erpul 《Environmental Earth Sciences》2010,60(6):1179-1187
Soil erosion is a major environmental problem that threatens the sustainability and productivity of agricultural areas. Assessment
and mapping of soil erosion are extremely important in the management and conservation of natural resources. The universal
soil loss equation (USLE/RUSLE) is an erosion model that predicts soil loss as a function of soil erodibility (K-factor), as well as topographic, rainfall, cover, and management factors. The traditional approach assumes that one soil
erodibility value represents the entire area of each soil series. Therefore, that approach does not account for spatial variability
of soil series. This study was carried out to evaluate the use of the sequential Gaussian simulation (SGS) for mapping soil
erodibility factor of the USLE/RUSLE methodology. Five hundred and forty-four surface soil samples (0–20 cm) were collected
from the study area to determine the soil erodibility. A simulation procedure was carried out on 300 realizations, and histogram
and semivariogram of the simulation were compared to the observed values. The results showed that the summary statistics,
histogram, and semivariogram of the simulation results were close to the observed values. In contrary to the traditional approach
and kriging, 95% confidence interval of the simulated realizations was formed in order to determine uncertainty standard deviation
map, and the uncertainty was explained numerically. The SGS produced a more reliable soil erodibility map and it can be more
successfully used for monitoring and improving effective strategies to prevent erosion hazards especially to improve site
specific management plans. 相似文献
15.
Hakan Alcik Oguz Ozel Yih-Min Wu Nurcan M. Ozel Mustafa Erdik 《Soil Dynamics and Earthquake Engineering》2011
Two recent catastrophic earthquakes that struck the Marmara Region on 17 August 1999 (Mw=7.4) and 12 November 1999 (Mw=7.2) caused major concern about future earthquake occurrences in Istanbul and the Marmara Region. As a result of the preparations for an expected earthquake may occur around Istanbul region, an earthquake early warning system has been established in 2002 with a simple and robust algorithm, based on the exceedance of specified thresholds of time domain amplitudes and the cumulative absolute velocity (CAV) levels (Erdik et al., 2003 [1]). In order to improve the capability of Istanbul earthquake early warning system (IEEWS) for giving early warning of a damaging earthquake in the Marmara Region, we explored an alternative approach with the use of a period parameter (τc) and a high-pass filtered vertical displacement amplitude parameter (Pd) from the initial 3 s of the P waveforms as proposed by Kanamori (2005) [2] and Wu and Kanamori (2005) 3 and 4. The empirical relationships both between τc and moment magnitude (Mw), and between Pd and peak ground velocity (PGV) for the Marmara Region are presented. These relationships can be used to detect a damaging earthquake within seconds after the arrival of P waves, and can provide on-site warning in the Marmara Region. 相似文献
16.
Volkan Yilmaz Berkant Konakoglu Cigdem Serifoglu Oguz Gungor Ertan Gökalp 《国际地球制图》2018,33(3):310-320
With the advent of unmanned aerial vehicles (UAVs) for mapping applications, it is possible to generate 3D dense point clouds using stereo images. This technology, however, has some disadvantages when compared to Light Detection and Ranging (LiDAR) system. Unlike LiDAR, digital cameras mounted on UAVs are incapable of viewing beneath the canopy, which leads to sparse points on the bare earth surface. In such cases, it is more challenging to remove points belonging to above-ground objects using ground filtering algorithms generated especially for LiDAR data. To tackle this problem, a methodology employing supervised image classification for filtering 3D point clouds is proposed in this study. A classified image is overlapped with the point cloud to determine the ground points to be used for digital elevation model (DEM) generation. Quantitative evaluation results showed that filtering the point cloud with this methodology has a good potential for high-resolution DEM generation. 相似文献
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18.
Hiroaki Yamanaka Ögur Tuna Özmen Kosuke Chimoto Mehmet Akif Alkan Muammer Tün Emrah Pekkan Oguz Özel Derya Polat Murat Nurlu 《Journal of Seismology》2018,22(5):1127-1137
We have explored 1D S-wave velocity profiles of shallow and deep soil layers over a basement at strong motion stations in Eskisehir Province, Turkey. Microtremor array explorations were conducted at eight strong motion stations in the area to know shallow 1D S-wave velocity models. Rayleigh wave phase velocity at a frequency range from 3 to 30 Hz was estimated with the spatial autocorrelation analysis of array records of vertical microtremors at each station. Individual phase velocity was inverted to a shallow S-wave velocity profile. Low-velocity layers were identified at the stations in the basin. Site amplification factors from S-wave parts of earthquake records that had been estimated at the strong motion stations by Yamanaka et al. (2017) were inverted to the S-wave velocities and Q-values of the sedimentary layers. The depths to the basement with an S-wave velocity of 2.2 km/s are about 1 km in the central part of the basin, while the basement becomes shallow as 0.3 km in the marginal part of the basin. We finally discussed the effects of the shallow and deep sedimentary layers on the 1D S-wave amplification characteristics using the revealed profiles. It is found that the shallow soil layers have no significant effects in the amplification at a frequency range lower than 3 Hz in the area. 相似文献
19.
Kurtulus Atasever Shogo Inanaga Toru Takeuchi Yuki Terazawa Oguz C. Celik 《地震工程与结构动力学》2020,49(15):1640-1661
There has been an increasing interest in using residual deformation as a seismic performance indicator for earthquake resistant building design. Self-centering braced structural systems are viable candidates for minimizing residual deformations following a major earthquake. Hence, this study proposes an alternative type of buckling restrained brace (BRB) with externally attached posttensioned (PT-BRB) carbon fiber composite cables (CFCCs). The steel core of the brace is used as an energy dissipator, whereas the CFCCs provide the self-centering force for minimizing residual story drifts. Three proof-of-concept specimens are designed, fabricated, and cyclically tested at different posttensioning force levels. The CFCC behavior to obtain cyclic response, including the anchorage system, is examined closely. A parametric study is also conducted to show the effect of the different configurations of PT-BRBs on the inelastic response. Furthermore, optimal brace parameters are discussed to realize design recommendations. The results indicated that the implementation of partially self-centering BRBs in building frames can lead to the target residual displacements. A stable behavior is obtained for the proposed PT-BRBs when subjected to the loading protocol specified in the American Institute of Steel Construction (AISC) 2016 Seismic Provisions. 相似文献
20.
Ozlem Karagoz Kosuke Chimoto Hiroaki Yamanaka Oguz Ozel Seckin Citak 《Bulletin of Earthquake Engineering》2018,16(1):23-43
On 24 May 2014, a Mw 6.9 earthquake occurred in the west of Gokceada Island, northern Aegean Sea. The earthquake was close to Canakkale, Enez, Tekirdag cities, and damaged 300 buildings in the Marmara Region, NW Turkey. We simulated its broadband (0.1–10 Hz) ground motions including 1D deep and shallow structures soil amplification effects at the 12 strong ground motion stations in the western Marmara Region. The 1D deep velocity structures from the focal layer to the engineering bedrock with an S-wave velocity of 0.78 km/s in different azimuthal directions were tuned by comparing the observed group-velocity dispersion curves of Rayleigh and Love waves from the mainshock with theoretical ones. We also added the shallow parts from previous surveys into the 1D models. Synthetic seismograms on the engineering bedrock were generated using the discrete wave number method with a source model and the 1D deep velocity structures. Then the surface motion was generated considering shallow soil amplification. The synthetic seismograms are generally in good agreement with the observed low and high-frequency parts at most of the stations indicating an appropriateness of the source model and the 1D structural model. 相似文献