33 research outputs found

    THE 2014 MW 6.9 NORTH AEGEAN TROUGH (NAT) EARTHQUAKE: SEISMOLOGICAL AND GEODETIC EVIDENCE

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    A strong earthquake (Mw 6.9) on 24 May 2014 ruptured the North Aegean Trough (NAT) in Greece, west of the North Anatolian Fault Zone (NAFZ). In order to provide unbiased constrains of the rupture process and fault geometry of the earthquake, seismological and geodetic data were analyzed independently. First, based on teleseismic long-period P- and SH- waveforms a point-source solution yielded dominantly right-lateral strike-slip faulting mechanism. Furthermore, finite fault inversion of broad-band data revealed the slip history of the earthquake. Second, GPS slip vectors derived from 11 permanent GPS stations uniformly distributed around the meizoseismal area of the earthquake indicated significant horizontal coseismic slip. Inversion of GPS-derived displacements on the basis of Okada model and using the new TOPological INVersion (TOPINV) algorithm permitted to model a vertical strike slip fault, consistent with that derived from seismological data. Obtained results are consistent with the NAT structure and constrain well the fault geometry and the dynamics of the 2014 earthquake. The latter seems to fill a gap in seismicity along the NAT in the last 50 years, but seems not to have a direct relationship with the sequence of recent faulting farther east, along the NAFZ

    3-D sediment-basement tomography of the Northern Marmara trough by a dense OBS network at the nodes of a grid of controlled source profiles along the North Anatolian fault

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    A 3-D tomographic inversion of first arrival times of shot profiles recorded by a dense 2-D OBS network provides an unprecedented constraint on the P-wave velocities heterogeneity of the upper-crustal part of the North Marmara Trough (NMT), over a region of 180 km long by 50 km wide. One of the specific aims of this controlled source tomography is to provide a 3-D initial model for the local earthquake tomography (LET). Hence, in an original way, the controlled source inversion has been performed by using a code dedicated to LET. After several tests to check the results trade-off with the inversion parameters, we build up a 3-D a priori velocity model, in which the sea-bottom topography, the acoustic and the crystalline basements and the Moho interfaces have been considered. The reliability of the obtained features has been checked by checkerboard tests and also by their comparison with the deep-penetration multichannel seismic profiles, and with the wide-angle reflection and refraction modelled profiles. This study provides the first 3-D view of the basement topography along the active North Anatolian fault beneath the Marmara Sea, even beneath the deepest part of three sedimentary basins of NMT. Clear basement depressions reaching down 6 km depth below the sea level (bsl) have been found beneath these basins. The North Imralı Basin located on the southern continental shelf is observed with a similar sedimentary thickness as its northern neighbours. Between Central and Çınarcık basins, the Central High rises up to 3 km depth below (bsl). Its crest position is offset by 10 km northwestward relatively to the bathymetric crest. On the contrary, Tekirdağ and Central basins appear linked, forming a 60-km-long basement depression. Beneath the bathymetric relief of Western High low velocities are observed down to 6 km depth (bsl) and no basement high have been found. The obtained 3-D Vp heterogeneity model allows the consideration of the 3-D supracrustal heterogeneity into the future earthquake relocations in this region. The topographic map of the pre-kinematic basement offers the possibility to take into account the locking depth variations in future geohazard estimations by geomechanical modelling in this region

    A study on the role of counselling service and follow-up in the use of family planning methods

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    Objective: The present study aimed to evaluate the effectiveness of counselling service and follow-up procedure for family planning in two suburban areas of the Kugukgekmece Health Education and Research District in Istanbul. Methods: Midwives were trained in family planning by physicians. Ten women for case and 10 women for control groups were chosen for each midwife from the follow up records of fertile women, and 455 women in total who did not use any family planning methods were chosen for case and control groups. The groups were followed up monthly, as case groups were given counselling service on family planning. Control groups received only routine health service. The attitudes of women in all groups were followed for two years. Then the program was extended to the whole district, and data related to the use of family planning methods for the last five years was evaluated. Results: Sixty seven point four percent of the women in the case groups and 43.4% of the control groups began using family planning methods when the program ended. The rate increased up to 78% for the following years and then saturated. Conclusion: The women in the district were put in touch with family planning users, and the use of family planning methods increased. For the use of modern family planning methods more efficiently in the community, the methods should be offered free of charge and counselling service should work in harmonious coordination

    Understanding tsunamis, potential source regions and tsunami-prone mechanisms in the Eastern Mediterranean

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    Historical tsunamis and tsunami propagation are synthesized in the Eastern Mediterranean Sea region, with particular attention to the Hellenic and the Cyprus arcs and the Levantine basin, to obtain a better picture of the tsunamigenic zones. Historical data of tsunami manifestation in the region are analysed, and compared with current seismic activity and plate interactions. Numerical simulations of potential and historical tsunamis reported in the Cyprus and Hellenic arcs are performed as case studies in the context of the nonlinear shallow-water theory. Tsunami wave heights as well as their distribution function are calculated for the Paphos earthquake of 11 May 1222 and the Crete earthquake of 8 August 1303 as illustrative examples depicting the characteristics of tsunami propagation, and the effects of coastal topography and near-shore amplification. The simulation studies also revealed that the long-normal distributions arc compatible with reported damage. Furthermore, it is necessary to note that high-resolution bathymetry maps are a crucial component in tsunami wave simulations, and this aspect is rather poorly developed in the Eastern Mediterranean. The current study also demonstrates the role of bottom irregularities in determining the wave-height distribution near coastlines. Assuming the probability of occurrence of destructive tsunamigenic earthquakes, these studies will help us to evaluate the tsunami hazard for the coastal plains of the Eastern Mediterranean Sea region. We suggest that future oceanographic and marine geophysical research should aim to improve the resolution of bathymetric maps, particularly for the details of the continental shelf and seamounts

    Courses for medical residents and trainers in Turkey for promotion of quality of reproductive health services: A pilot study

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    In order to provide high quality services in reproductive health, training of health professionals is essential. In Turkey, a project for in-service training of medical residents was conducted in 2003 under the aegis of the Human Resources Development Foundation, the Turkish Ministry of Health and UNFPA. The project included a needs assessment, training programme development and evaluation activities. A seven-day course was developed to train institutional trainers in both training skills and reproductive health information. Fourteen experienced master trainers conducted four courses for 67 institutional trainers from 37 hospital departments in four cities, who in turn conducted a three-day programme on reproductive health topics in their respective institutions, using interactive teaching methods. 163 residents from departments of obstetrics and gynaecology, family medicine, urology, public health and paediatrics participated. Over three-quarters of trainers and residents who participated in the programme approved of the content of the courses. A limited number of topics, e.g. sexual health and adolescent reproductive health, were thought to need more attention. Trainers cited improvements in doctor-patient communication and quality of outpatient and in-patient care, and initiation of counselling in their institutions. We conclude that this training programme, attended by trainers and participants from different disciplines and using interactive teaching methods, has been successful as an effective training model for medical residents. The establishment of an ongoing collaboration between the Ministry of Health and other institutions involved in resident training in Turkey is needed to ensure the expansion of this programme to oil residents in training. (C) 2004 Reproductive Health Matters. All rights reserved

    Development of training of trainers programmes and evaluation of their effectiveness in Istanbul, Turkey

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    This report presents an evaluation of the impact of the 'Training of Trainers' (TOT) courses conducted since 1997. The effects of TOT programmes were studied using a questionnaire given to the course participants immediately after and again following a minimum period of six months after completion of the course. The 85 participants included in this analysis were medical teachers from the Istanbul Faculty of Medicine, of whom 17% were instructors, 39% were associate professors and 44% full professors. Some 72% of the medical teachers stated that they were able to implement the knowledge/skills they had acquired during the TOT course in their teaching. The majority of the participants reported more feedback from students and enhancement of student-faculty interaction in their teaching experience after the course. These results appear promising and indicate that TOT courses indeed motivate the teaching staff and provide them with tools and opportunities for more effective teaching. They also appear to have a lasting impact

    Rupture kinematics of 2020 January 24 Mw6.7 Doǧanyol-Sivrice, Turkey earthquake on the East Anatolian Fault Zone imaged by space geodesy

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    Here, we present the results of a kinematic slip model of the 2020 Mw 6.7 Doǧanyol-Sivrice, Turkey Earthquake, the most important event in the last 50 yr on the East Anatolian Fault Zone. Our slip model is constrained by two Sentinel-1 interferograms and by 5 three-component high-rate GNSS (Global Navigation Satellite System) recordings close to the earthquake source. We find that most of the slip occurs predominantly in three regions, two of them at between 2 and 10 km depth and a deeper slip region extending down to 20 km depth. We also relocate the first two weeks of aftershocks and find a distribution of events that agrees with these slip features. The HR-GNSS recordings suggest a predominantly unilateral rupture with the effects of a directivity pulse clearly seen in the waveforms and in the measure peak ground velocities. The slip model supports rupture propagation from northeast to southwest at a relatively slow speed of 2.2 km s-1 and a total source duration of ∼20 s. In the absence of near-source seismic stations, space geodetic data provide the best constraint on the spatial distribution of slip and on its time evolution. © 2020 The Author(s). Published by Oxford University Press on behalf of The Royal Astronomical Society
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