Understanding Extragalactic Hydroxyl

Hydroxyl (OH) is one of the few molecules in space showing both maser emission and absorption. In the Milky Way, hydroxyl has been found in various environments such as stellar envelopes, star-forming regions, and HII regions, tracing the physical states of the interstellar medium. Extragalactic OH has been found to provide essential information about the dusty and obscuring material within the inner kiloparsec region of active galaxies. At angular resolution of a few tens of parsecs, OH shows a rather complicated spatial distribution and the interpretation of the circumnuclear environment is rather difficult. Based on results obtained from low- and high-resolution observations, the diagnostic tools of OH will be reviewed and the strategies to further investigate extragalactic OH will be discussed.     

Seismic hazard studies for Gaziantep city in South Anatolia of Turkey

Seismic hazard studies were conducted for Gaziantep city in the South Anatolia of Turkey. For this purpose, a new attenuation relationship was developed using the data of Zaré and Bard and accelerations were predicted employing this new equation. Deterministic approach, total probability theorem and GIS methodology were all together utilized for the seismic assessments. Seismic hazard maps with 0.25° grid intervals considering the site conditions were produced by the GIS technique. The results indicated that the acceleration values by the GIS hazard modelings were matched with the ones from the deterministic approach, however, they were underestimated comparing with the total probability theorem. In addition, the GIS based seismic hazard maps showed that the current seismic map of Turkey fairly yields conservative acceleration values for the Gaziantep region. Therefore, the constructed GIS hazard models are offered as a base map for a further modification of the current seismic hazard map.     

Biodegradation effects over different types of coastal rocks

Modern coastal areas have natural and transported rocks (armourstone) on which various types of organisms live. Burrowing, boring and feeding by these organisms can destroy or modify the coastal rocks and hence change the coastal morphology. Two rock types and three dominant types of organisms have been studied in Mersin Bay, Eastern Mediterranean of southern Turkey. In this study area, Plio-Quaternary conglomerates and variously aged limestone armourplates have been affected by Phoronida worms, bivalve Brachidontes pharaonis (Fischer P. 1870) and the limpet Patella sp. Phoronida colonies were found covering the hard substratum as a mat and form tubular endolithes of 35.0 mm depth and 1.5 mm diameter, whilst Brachidontes pharaonis (Fischer P. 1870) form 44 mm deep vase-shaped gastrochaenolites. The bioerosive activity of Limpet Patella sp., found intertidal and within the spray zone, cannot be significantly observed on the rocks over short time periods. The soft sandy matrix of the conglomerates present were found to disintegrate by bioerosional processes, with the released gravels being transported and deposited onto the beach. Within the armourstone limestone blocks, a maximum of 44.0 mm deep holes developed after 50–60 years. However, these biological activities do not threaten the stability of the blocks due to their hard and homogeneous internal structure. Furthermore, the organism colonies that cover these rocks as a strong mat (maximum 29.0 mm) act to protect their surfaces from further biological attack and wave action.     

Biostratigraphy of the Çeşmeler and Elmalι Dere formations: First records of upper Cretaceous planktonic foraminifera and radiolarians from the Eastern Pontides (Maçka,Trabzon, Turkey)

Upper Cretaceous pelagic deposits outcropping in the Maçka (Trabzon) region include radiolarians and pelagic foraminifera. The Çatak Group represented by the volcano-sedimentary successions consists of three formations having different properties. Two sections, ÇTK1 and ÇTK2, are selected from the Çe meler and Elmalι Dere formations, respectively, establishing the biostratigraphy of outcropping sedimentary units. A total of 17 species of Whiteinella, Helvetoglobotruncana, Marginotruncana, Dicarinella, Praeglobotruncana, Archaeoglobigerina and Hedbergella demonstrating the early Turonian–Coniacian are established in the ÇTK1 stratigraphic section. The early Turonian radiolarian fauna consisting of Halesium sexangulum Pessagno, 1971, Crucella cachensis Pessagno, 1971, Stichomitra communis Squinabol, 1903 is also defined in the same section. A total of 30 species of Crucella, Halesium, Pessagnobrachia, Patulibracchium, Alievium, Archaeospongoprunum, Dicyomitra, Stichomitra, Diacanthocapsa, Dactiyliodiscus, Amphipydax, Pseudoaulophocus, Acaeniotyle, Archaeodictyomitra, Actinomma, Xitus, Neosciadocapsidae characterizing the early and late Turonian, as well as the Coniacian–early Santonian are recognized from red-coloured pelagic limestones of the ÇTK2 section. Also, planktonic foraminifera species of Marginotruncana, Hedbergella, Heterohelix, Globotruncana, Globotruncanita, Archaeoglobigerina, Dicarinella characterizing the Coniacian–Santonian are described in the thin sections of the same samples. The age of red-coloured limestones is identified as the Coniacian–Santonian benefit from radiolarians and pelagic foraminifera. Consequently, radiolarians and pelagic foraminifera within sedimentary successions of the investigation area are distributed in two intervals that coincide with the early Turonian–Coniacian and Coniacian–Santonian intervals.     

Relative tectonic activity assessment of the Çameli Basin,Western Anatolia,using geomorphic indices

Western Anatolia is one of the world’s most seismically active regions. A nearly N–S-oriented extension caused the formation of E–W- and NE–SW-trending major grabens, creating the potential for earthquakes with magnitudes ≥ 5. The fault segments of the NE-trending Çameli Basin were evaluated using geomorphic indices, common tools for assessment of relative tectonic activity in such areas. Quantitative measurement of geomorphic indices including mountain-front sinuosity (Smf; 1.35–2.39), valley floor width-to-height ratios (Vf; 0.08?0.37), and hypsometric integral (HI; 0.31–1.05) suggest relatively higher tectonic activity along western and southern part of the basin. Hypsometric curves for all segments of the faults mostly exhibit concave or straight profiles, signifying existence of young mountain fronts in the Çameli Basin. These calculations indicate that the Çameli Basin is tectonically active and, southern/south-western areas of this depression have earthquake potential, consistent with epicentres of recent earthquakes, occurred along some fault segments. Possible reason of this activity seems to be related to the E–W-trending corridor lying between the Gulf of Gökova and south-eastern part of the Çameli Basin, represented by active normal faults. These findings should be valid beyond the Çameli Basin for similar situations along the Isparta Angle’s western margin.     

Active tectonic and palaeoseismological features of the western section of Mustafakemalpaşa Fault; Bursa,NW Anatolia

The Mustafakemalpa?a Fault (MF), located among Manyas, Ulubat and Orhaneli faults, is a right lateral strike-slip and 47 km in length. The MF begins with a pressure ridge at the west and exhibits complex jog terminations at east ends in restraining left stepovers. The western section of the fault bounds Miocene and Quaternary units and continues towards ?lyasç?lar. The central segment of the fault, starts with approximately 750-m leftward stepover, exhibits a sinusoidal geometry between Kapakl?oluk and Kabulbaba. In this section, MF traverses mountainous terrain and cuts Ophiolite, Jurassic limestones and Miocene detritals, forming dextral faulting features and gaining reverse component. The eastern section exhibits left stepping en-echelon pattern and consists 2.5-km offset on the Orhaneli River. In this study, palaeoseismological findings related to the Holocene activity and active tectonic properties of the MF are presented. The trenches exposed mismatched stratigraphy, demonstrating evidence of events across the fault. We identified three events (before BC 2190, later AD 1425 and 1850) that have occurred during the past 4000 years. We suggest a long non-characteristic recurrence interval and ~0.7 mm/y slip-rate for MF, based on trench data and offset of the Late Pliocene drainage of Orhaneli River.     

Adaptation of hurricane risk perception scale to earthquake risk perception and determining the factors affecting women's earthquake risk perception

Natural Hazards - Worldwide studies show that gender is an important variable affecting disaster risk perception and that women have high levels of disaster risk perception. The objective of this...