October 23, 2011 Turkey/Van–Ercis earthquake: structural damages in the residential buildings     

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   

Transferring the international DRR policy into the local context     

Elif Daldeniz  Nihal Ekin Erkan 《Natural Hazards》2013,66(2):1273-1285

The disaster experiences of the past resulted in the need for a new international policy. The paper examines the transfer of the international policy for disaster risk reduction (DRR) into a local context, Turkey and Turkish, where new and old perspectives meet. Analyzed is a corpus consisting of two texts, with the purpose of examining the concepts’ actual use and contexts shaped by different attitudes, based on the three-dimensional framework of critical discourse analysis, translation studies and conceptual history. The concept transfer from international to the local level inevitably involves translation. The texts included “new” DRR terms as a result of the concealed translation attempts to adjust the old and contemporary terminologies. Thus, non-functional terms with blurred meanings arose. The awareness that such processes of transfer are complex would help to overcome this kind of simplistic top-down approaches and to give priority to “communicative labor.” The framework is not presented due to space limitations. It was also observed that the Turkish terminology lacks clear definitions. To affirm this, an in-depth analysis is needed. Terms transferred across contexts may end lacking conceptualizations due to non-functional translation choices. When adopting new social policies, this can be overcome through making effort for communication. This research looks at conceptual struggles related to social issues from a different aspect. The vague terms and inefficiencies in social implementations can be avoided by authorities being aware that discourse, translation and their production are parts of social action.  相似文献   

Late Quaternary evolution of the Çanakkale Strait region (Dardanelles, NW Turkey): implications of a major erosional event for the postglacial Mediterranean-Marmara Sea connection   总被引：2，自引：2，他引：0  

Erkan Gökaşan  Hüseyin Tur  Mustafa Ergin  Tolga Görüm  Fatma Gül Batuk  Nurcan Sağcı  Timur Ustaömer  Ozan Emem  Hakan Alp 《Geo-Marine Letters》2010,30(2):113-131

Seismic and bathymetric data from the Çanakkale Strait and its extensions onto the shelves of the Marmara and Aegean seas indicate that the strait was formed mainly by an erosional event. Four seismic units are observed on seismic profiles. The lower two of these (units 4 and 3) constitute the basement of a regionally widespread erosional unconformity (ravinement), which developed during marine isotope stage 2 (MIS 2). The two upper units (units 2 and 1), which overlie the ravinement surface, form a higher-order sequence. Sequence stratigraphic analysis indicates that units 2 and 1 deposited as lowstand and highstand systems tracts respectively, since the end of MIS 2. The transgressive systems tract is represented by a major erosional event which occurred throughout the Çanakkale sill area when the Mediterranean-Marmara Sea connection and, hence, the Çanakkale Strait was formed. The existence of the erosive ?arköy Canyon along the shelf edge of the southern Marmara Sea demonstrates that the flow direction causing the erosion was from south to north, thus proving that it was produced by Mediterranean water flowing over the sill into the Marmara Sea basin.  相似文献   

Morpho-tectonic evolution of the Marmara Sea inferred from multi-beam bathymetric and seismic data   总被引：1，自引：6，他引：1  

Erkan?Goka?anEmail author  Timur?Usta?mer  Cem?Gazio?lu  Zeki?Ya?ar?Yucel  Kurultay??ztürk  Hüseyin?Tur  Berkan?Ecevito?lu  Bu?ser?Tok 《Geo-Marine Letters》2003,23(1):19-33

In an initial stage, the Sea of Marmara developed as a graben and, in due course, considerable volumes of sediments were deposited in this basin. Before 200 ka, a new fault (New Marmara Fault) cutting through the whole basin developed, which postdated large sub-marine land sliding in the western part of the basin. This mass movement created the Western Ridge. The initiation of this strike-slip fault indicates that the extensional stress regime was replaced by a new, shearing stress field. In the eastern part of the Marmara Basin, the New Marmara Fault consists of two branches. The northern one replaces the normal faulting at the bottom of the northeastern slope of the basin. As a result, this slope has been rejuvenated. The southern branch is located along the central axis of the basin, forming the major extension of the North Anatolian Fault Zone within the region. Two restraining bends were formed because of the counterclockwise rotation of that part of the Anatolian Block. This resulted the uplifting of the Eastern Ridge and the formation of the positive flower structure within the Tekirdag Basin. The establishment of the compressional regime around the Sea of Marmara also resulted in the northwest–southeast shortening of the initial Marmara Basin.  相似文献   

The Great Rift Valley of Madagascar: An extension of the Africa–Somali diffusive plate boundary?     

Timothy M. Kusky  Erkan Toramanand Tsilavo Raharimahefa 《Gondwana Research》2007,11(4):577-579

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The Hasan Dagi stratovolcano (Central Anatolia, Turkey): evolution from calc-alkaline to alkaline magmatism in a collision zone   总被引：1，自引：0，他引：1  

Catherine Deniel  Erkan Aydar  Alain Gourgaud 《Journal of Volcanology and Geothermal Research》1998,87(1-4)

The Hasan Dagi volcano is one of the two large Plio-Quaternary volcanoes in Cappadocia (Central Anatolia, Turkey). Three stages of edifice construction have been identified for this volcano: Paleovolcano, Mesovolcano and Neovolcano. Most samples from Hasan Dagi volcano are calc-alkaline and define an almost complete trend from basaltic andesite to rhyolite. However, the more recent (Neovolcano) mafic samples are alkaline basalts. The mineralogical and geochemical characteristics of the oldest lavas (Keçikalesi (13 Ma) and Paleo-Hasan Dagi (7 Ma)) are significantly different from those of the younger lavas (Meso- and Neo-Hasan Dagi (<1 Ma)). Calcic plagioclase and pigeonite are typically observed in these older lavas. The Paleovolcano basalts are depleted in alkalis and display a tholeiitic tendency whereas the differentiated lavas are depleted in Na₂O but enriched in K₂O compared to younger lavas. There is an evolution through time towards higher TiO₂, Fe₂O₃^*, MgO, Na₂O and K₂O and lower Al₂O₃ and SiO₂ which is reflected in the basalt compositions. All the basalts display multi-element patterns typical of continental margin magmas with a significant enrichment in LILE (K, Rb, Ba and Th) and LREE and strong (Paleovolcano) to moderate (Meso- and Neovolcano) negative Nb, Zr and Ti anomalies. However, the younger basalts are the most enriched in incompatible elements, in agreement with their alkaline affinities and do not systematically display negative HFSE anomalies. REE data suggest an hydrous amphibole-bearing crystallization history for both Meso- and Neovolcano lavas. The distinction between the older and younger lavas is also apparent in trace element ratios such as Nb/Y, Ti/Y and Th/Y. These ratios indicate the role of a subducted component±crustal contamination in the genesis of the Hasan Dagi lavas, particularly for the oldest lavas (Keçikalesi and Paleo-Hasan Dagi). The decreasing influence of this component through time, over the last 6–7 m.y., has been accompanied by an increasing contribution of melt-enriched lithosphere. Although the range of variation of Sr, Nd and Pb isotopic ratios is small (0.70457–0.70515; 0.51262–0.51273; 18.80–18.94; 15.64–15.69; 38.87–39.10), it also reflects the evolution of the magma sources through time. Indeed, the youngest (Neovolcano) and most primitive basalts display significantly lower ⁸⁷Sr/⁸⁶Sr than the Paleo- and Mesovolcano basalts, whereas the Mesovolcano basalts display more radiogenic Pb than Paleovolcano samples. Magma mixing processes between initially heterogeneous and/or variably contaminated magmas may account for the genesis of the less differentiated and intermediate lavas (48–57% SiO₂). Meso- and Neovolcano differentiated lavas (60–68% SiO₂) are either derived from the analyzed basalts or from more primitive and more depleted magmas by fractional crystallization±some crustal contamination (AFC). Furthermore, the highly differentiated samples (72–75% SiO₂) are not strongly contaminated. The strong calc-alkaline character of Hasan Dagi lavas, in the absence of contemporaneous subduction, must reflect the heritage of the early subduction of the Afro–Arabian plate under the Eurasian plate. The evolution towards alkaline compositions through time is clearly related to the development of extensional tectonics in Central Anatolia in the Late Miocene.  相似文献   

Factors controlling the morphological evolution of the Çanakkale Strait (Dardanelles, Turkey)     

Erkan Gökaşan  Mustafa Ergin  Mustafa Özyalvaç  Halil İbrahim Sur  Hüseyin Tur  Tolga Görüm  Timur Ustaömer  Fatma Gül Batuk  Hakan Alp  Halim Birkan  Ahmet Türker  Erhan Gezgin  Murat Özturan 《Geo-Marine Letters》2008,28(2):107-129

Seismic profiling, bathymetric and physical oceanographic data collected from the Çanakkale Strait revealed that the morphological evolution of the strait has been controlled by tectonic activity, and sediment erosion and deposition. Sediments in the strait have been sourced mostly by rivers draining the Biga Peninsula during lowstand periods. In highstand periods, by contrast, deposits in the strait were reworked by currents. The seafloor morphology of the Çanakkale Strait is also controlled by a sequence of factors ranging from tectonics to current erosion and deposition. Channel deposits overlying the basement are being eroded at the narrower, meandering central section of the strait (the Nara Passage) due to high current velocities. The eroded sediments are deposited in the relatively linear and wider, northern and southern sectors of the strait exposed to low current velocities. As a result, the high-energy areas are more deeply incised due to the erosion, whereas deposition elevates the seafloor in the areas exposed to lower current energy. Three strike-slip faults, which possibly relate to the activity of the North Anatolian Fault Zone, are responsible for the irregular shape of the strait and this, in turn, controls the current velocity along the strait. The high-energy conditions probably commenced with the latest invasion of Mediterranean waters some 12 ka b.p., and have continued as a two-layered current system to the present day.  相似文献   

Faulting, mass-wasting and deposition in an active dextral shear zone, the Gulf of Saros and the NE Aegean Sea, NW Turkey   总被引：1，自引：1，他引：0  

Timur Ustaömer  Erkan Gökaşan  Hüseyin Tur  Tolga Görüm  Fatma Gül Batuk  Doğan Kalafat  Hakan Alp  Berkan Ecevitoğlu  Halim Birkan 《Geo-Marine Letters》2008,28(3):171-193

Structural, mass-wasting and sedimentation processes along an active dextral shear zone beneath the Gulf of Saros and the NE Aegean Sea were investigated on the basis of new high-resolution swath bathymetric data and multi-channel seismics. A long history of dextral shearing operating since the Pliocene culminated in the formation of a NE-SW-trending, ca. 800-m-deep basin (the so-called inner basin) in this region, which is bordered by a broad shelf along its northern and eastern sides and a narrow shelf at the southern side. The western extension of the North Anatolian Fault Zone (the Ganos Fault) cuts the eastern shelf along a narrow deformation zone, and ends sharply at the toe of the slope, where the strain is taken up by two NE-SW-oriented fault zones. These two fault zones cut the basin floor along its central axis and generate a new, Riedel-type pull-apart basin (the so-called inner depression). According to the bathymetric and seismic data, these basin boundary fault zones are very recent features. The northern boundary of the inner depression is a through-going fault comprising several NE-SW- and E-W-oriented, overlapping fault segments. The southern boundary fault zone, on the other hand, consists of spectacular en-echelon fault systems aligned in NE–SW and WNW–ESE directions. These en-echelon faults accommodate both dextral and vertical motions, thereby generating block rotations along their horizontal axis. As the basin margins retreat, the basin widens continuously by mass-wasting of the slopes of the inner basin. The mass-wasting, triggered by active tectonics, occurs by intense landsliding and channel erosion. The eroded material is transported into the deep basin, where it is deposited in a series of deep-sea fans and slumps. The high sedimentation rate is reflected in an over 1,500-m-thick basin fill which has accumulated in Pliocene–Quaternary times.  相似文献   

A mantle- and a lower crust-derived bimodal suite in the Yusufeli (Artvin) area, NE Turkey: trace element and REE evidence for subduction-related rift origin of Early Jurassic Demirkent intrusive complex     

Abdurrahman Dokuz  Erkan Tanyolu  Salim Genç 《International Journal of Earth Sciences》2006,95(3):370-394

The Yusufeli area, in the Eastern Black Sea Region of Turkey, contains a crystalline complex that intruded into the Carboniferous metamorphic basement and is composed of two intrusive bodies: a gabbro-diorite and a tonalite-trondhjemite. The mafic body (45–57 wt% SiO₂) displays a broad lithological spectrum ranging from plagioclase-cumulate to quartz diorite. Primitive varieties of the body have Mg-number, MgO and Cr contents that are close to those expected for partial melts from mantle peridotite. Data are consistent with the magma generation in an underlying mantle wedge that was depleted in Zr, Nb and Ti, and enriched in large ion lithophile elements (K, Rb, Ba, Th). However, high Al₂O₃, CaO and generally low Ni (<65 ppm) contents are not in agreement with the unfractionated mantle-derived primitive magmas and require some Al₂O₃- and CaO-poor mafic phases, in particular, olivine and orthopyroxene. Absence of orthopyroxene in crystallization sequence, uralitization, and a common appearance of clinopyroxene surrounded by hornblende imply an anhydrous phase fractionated from highly hydrous (5–6%) parent. Geochemical modelling suggests derivation by 15–20% melting of a depleted-lherzolitic mantle. The tonalite-trondhjemite body (58–76 wt% SiO₂) ranges in composition from quartz diorite to granodiorite with a low-K calc-alkaline trend. Although LILE- and LREE- enriched characteristics of the primitive samples imply a metasomatic sub-arc mantle for their source region, low MgO, Ni and Cr concentrations rule out direct derivation from the mantle wedge. Also, lack of negative Eu anomalies suggests an unfractionated magma and precludes a differentiation from the diorites of mafic body, which show negative Eu anomalies. Their Na enrichments relative to Ca and K are similar to those of Archean tonalites, trondhjemites and granodiorites and Cenozoic adakites. However, they exhibit important geochemical differences from them, including low-Al (<15 wt%) contents, unfractionated HREE patterns and evolution towards the higher Y concentrations and lower Sr/Y ratios within the body. All these features are obtained in experimentally produced melts from mafic rocks at low pressures (≤5 kbar) and also widespread in the rocks of arc where old (Upper Cretaceous or older) oceanic crust is being subducted. Major and REE modelling supports formation of the quartz dioritic parent to the felsic intrusive rocks by 70% partial melting of a primitive gabbroic sample (G694). Therefore, once taking into account the extensional conditions prevailing in the Pontian arc crust in Early Jurassic time, former basic products (gabbros) seem to be the most appropriate source for the tonalite-trondhjemite body. Magmatic emplacement of stratigraphically similar lithologies in the Pulur Massif, just southwest of the Yusufeli, was dated to be 184 Ma by the ⁴⁰Ar/³⁹Ar method on amphibole, and is compatible with the initiation of Early Jurassic rifting in the region.  相似文献   

First evidence of a distal early Holocene ash layer in Eastern Mediterranean deep-sea sediments derived from the Anatolian volcanic province     

Y. Hamann  S. Wulf  O. Ersoy  W. Ehrmann  E. Aydar  G. Schmiedl 《Quaternary Research》2010,73(3):497-506

A hitherto unknown distal volcanic ash layer has been detected in a sediment core recovered from the southeastern Levantine Sea (Eastern Mediterranean Sea). Radiometric, stratigraphic and sedimentological data show that the tephra, here termed as S1 tephra, was deposited between 8970 and 8690 cal yr BP. The high-silica rhyolitic composition excludes an origin from any known eruptions of the Italian, Aegean or Arabian volcanic provinces but suggests a prevailing Central Anatolian provenance. We compare the S1 tephra with proximal to medial-distal tephra deposits from well-known Mediterranean ash layers and ash fall deposits from the Central Anatolian volcanic field using electron probe microanalyses on volcanic glass shards and morphological analyses on ash particles. We postulate a correlation with the Early Holocene ‘Dikkart?n’ dome eruption of Erciyes Da? volcano (Cappadocia, Turkey). So far, no tephra of the Central Anatolian volcanic province has been detected in marine sediment archives in the Eastern Mediterranean region. The occurrence of the S1 tephra in the south-eastern part of the Levantine Sea indicates a wide dispersal of pyroclastic material from Erciyes Da? more than 600 km to the south and is therefore an important tephrostratigraphical marker in sediments of the easternmost Mediterranean Sea and the adjacent hinterland.  相似文献