排序方式： 共有53条查询结果，搜索用时 15 毫秒
41.
42.
43.
Erkan Çelebi Muharrem Aktas Naci Çağlar Aşkın Özocak Mustafa Kutanis Necati Mert Zeki Özcan 《Natural Hazards》2013,65(3):2287-2310
On October 23, 2011, a magnitude of Mw 7.2 earthquake struck the Van province in eastern Turkey which caused approximately 600 life loss and 4,000 injured people. Although the recorded peak ground accelerations were relatively low (0.15–0.2 g) compared with that of other recent destructive Turkish earthquakes and the code-based design response spectrum, a large number of reinforced concrete buildings with 4–6 stories and non-engineered masonry buildings were either heavily damaged or collapsed in the region. Based on the post-earthquake technical inspections, the goal of this paper is to introduce major reasons for structural damages in the disaster area and to discuss these failures along with the approaches given in the design code which is renewed after August 17, 1999 Marmara Earthquake. Some remarkable lessons learned from earthquake-induced failures and damages specific to building construction techniques are presented in this paper. 相似文献
44.
İbrahim Uysal E. Yalçın Ersoy Orhan Karslı Yildirim Dilek M. Burhan Sadıklar Chris J. Ottley Massimo Tiepolo Thomas Meisel 《Lithos》2012
We present new, whole-rock major and trace element chemistry, including rare earth elements (REE), platinum-group elements (PGE), and Re–Os isotope data from the upper mantle peridotites of a Cretaceous Neo-Tethyan ophiolite in the Mu?la area in SW Turkey. We also report extensive mineral chemistry data for these peridotites in order to better constrain their petrogenesis and tectonic environment of formation. The Mu?la peridotites consist mainly of cpx-harzburgite, depleted harzburgite, and dunite. Cpx-harzburgites are characterized by their higher average CaO (2.27 wt.%), Al2O3 (2.07 wt.%), REE (53 ppb), and 187Os/188Os(i) ratios varying between 0.12497 and 0.12858. They contain Al-rich pyroxene with lower Cr content of coexisting spinel (Cr# = 13–22). In contrast, the depleted harzburgites and dunites are characterized by their lower average CaO (0.58 wt.%), Al2O3 (0.42 wt.%), and REE (1.24 ppb) values. Their clinopyroxenes are Al-poor and coexist with high-Cr spinel (Cr# = 33–83). The 187Os/188Os(i) ratios are in the range of 0.12078–0.12588 and are more unradiogenic compared to those of the cpx-harzburgites.Mineral chemistry and whole rock trace and PGE data indicate that formation of the Mu?la peridotites cannot be explained by a single stage melting event; at least two-stages of melting and refertilization processes are needed to explain their geochemical characteristics. Trace element compositions of the cpx-harzburgites can be modeled by up to ~ 10–16% closed-system dynamic melting of a primitive mantle source, whereas those of the depleted harzburgites and dunites can be reproduced by ~ 10–16% open-system melting of an already depleted (~ 16%) mantle. These models indicate that the cpx-harzburgites are the products of first-stage melting and low-degrees of melt–rock interaction that occurred in a mid-ocean ridge (MOR) environment. However, the depleted harzburgites and dunites are the product of second-stage melting and related refertilization which took place in a supra subduction zone (SSZ) environment. The Re–Os isotope systematics of the Mu?la peridotites gives model age clusters of ~ 250 Ma, ~ 400 Ma and ~ 750 Ma that may record major tectonic events associated with the geodynamic evolution of the Neo-Tethyan, Rheic, and Proto-Tethyan oceans, respectively. Furthermore, > 1000 Ma model ages can be interpreted as a result of an ancient melting event before the Proto-Tethys evolution. 相似文献
45.
Sedat İnan Alican Kop Hasan Çetin Furkan Kulak Zümer Pabuçcu Cemil Seyis Semih Ergintav Onur Tan Ruhi Saatçılar M. Nuri Bodur 《Natural Hazards》2012,62(2):575-591
Soil gas radon release patterns have been monitored continuously for more than 3 years in the Eastern Mediterranean Province (EMP) (Southern Turkey), alongside regional seismic events, providing a multidisciplinary approach. In the period from January 2008 to January 2011, 14 earthquakes M L ≥4 occurred in the study area. By monitoring the sites for more than 3 years, the site-characteristic patterns of soil radon emanation of each site have become evident. Radon emanation data show seasonal (semi-annual) variation characteristics; high soil radon values are between May and October and low soil radon values are between November and April. With available rainfall data, the soil gas radon data can be more reliably evaluated. It is shown in this paper that if radon emanation data are available over sufficiently long periods of time and baseline data (and their seasonal variations) are known with certainty for each monitoring site, then the observation of positive anomalies might provide a correlation or connection to seismic activity. 相似文献
46.
Ümİt Avşar Erşan Türkoğlu Martyn Unsworth İlyas Çağlar Bülent Kaypak 《Pure and Applied Geophysics》2013,170(3):409-431
The collision between the Arabian and Eurasian plates in eastern Turkey causes the Anatolian block to move westward. The North Anatolian Fault (NAF) is a major strike-slip fault that forms the northern boundary of the Anatolian block, and the Erzincan Basin is the largest sedimentary basin on the NAF. In the last century, two large earthquakes have ruptured the NAF within the Erzincan Basin and caused major damage (M s = 8.0 in 1939 and M s = 6.8 in 1992). The seismic hazard in Erzincan from future earthquakes on the NAF is significant because the unconsolidated sedimentary basin can amplify the ground motion during an earthquake. The amount of amplification depends on the thickness and geometry of the basin. Geophysical constraints can be used to image basin depth and predict the amount of seismic amplification. In this study, the basin geometry and fault zone structure were investigated using broadband magnetotelluric (MT) data collected on two profiles crossing the Erzincan Basin. A total of 24 broadband MT stations were acquired with 1–2 km spacing in 2005. Inversion of the MT data with 1D, 2D and 3D algorithms showed that the maximum thickness of the unconsolidated sediments is ~3 km in the Erzincan Basin. The MT resistivity models show that the northern flanks of the basin have a steeper dip than the southern flanks, and the basin deepens towards the east where it has a depth of 3.5 km. The MT models also show that the structure of the NAF may vary from east to west along the Erzincan Basin. 相似文献
47.
Fatma Aşılıoğlu Yalçın D. Memlük 《Journal of the Indian Society of Remote Sensing》2017,45(3):553-567
Immovable cultural properties constituting cultural heritage centre upon regions that have the level of natural features required for basic human needs. Such regions constitute a space with characteristics of an eco-cultural subregion and they do not have any administrative or geographical boundaries. Aims of this study are to introduce the concept of eco-cultural subregion, which is the holistic expression of natural features together with cultural heritage, to the literature; to present a method in identifying geographical boundaries of subregions; and to formulate a classification system. The research was conducted in the Phrygian Valley, which is one of the most important centres of ancient Phrygians in Western Anatolia, using a method based on GIS-MCDM (Geographic Information System-Multiple Criteria Decision Making). The selected MCDM technique was Simos Procedure. Natural features and cultural heritage were considered together and the entire Phrygian Valley was approached as both an ecological and a cultural region. Ecological features were analysed using 7 main and 17 subfactors, while cultural heritage was analysed using 2 main factors and 15 subfactors. Simos Procedure was employed in the assignment of weight for main factors and subfactors. First 17 ecological subregions with similar characteristics under 4 levels were identified. Considering their cultural heritage values, a classification system was formulated and eco-cultural subregions were expressed in level/degree in this system. In consequence of this procedure boundaries of eco-cultural subregions were drawn and mapped. This classification also enabled to identify the concept of eco-cultural subregion which is not found in the literature. It is expected that eco-cultural subregions will provide to discuss ecological features and cultural heritage holistically in conservation and planning studies. 相似文献
48.
49.
Serap Kahraman Türkay Baran İ. Aydin Saatçi Müjgan Şalk 《Pure and Applied Geophysics》2008,165(2):331-347
A probabilistic seismic hazard analysis (PSHA) for Western Anatolia is presented using the Gutenberg-Richter (G-R) frequency-magnitude
relation. Since the modeling is sensitive to the location of seismotectonics boundaries, to use the information content of
the observed earthquake data, as a general rule the borders of the affected area are extended. In this study, the effect of
the region’s definition on the G-R model is debated on the Western Anatolian region, which is one of the most seismically
active and rapidly deforming regions of the world throughout the ages. Calculations are carried out for two subregions and
one combined region as a whole using the seismic catalog from 1900 to 2005. The data sets are determined by the region’s borders
with the parameters computed according to these data sets by the least-squares and maximum likelihood methods, and then future
predictions are estimated via these parameters. Comparing the results with historical earthquake records, most appropriate
regional borders for Western Anatolia are defined, and for this new region G-R model parameters are obtained. 相似文献
50.