S U M M A R YWe discuss the subsurface structure of the Karadere-Duzce branch of the North Anatolian Fault based on analysis of a large seismic data set recorded by a local PASSCAL network in the 6 months following the M w = 7.4 1999 Izmit earthquake. Seismograms observed at stations located in the immediate vicinity of the rupture zone show motion amplification and long-period oscillations in both P-and S-wave trains that do not exist in nearby off-fault stations. Examination of thousands of waveforms reveals that these characteristics are commonly generated by events that are well outside the fault zone. The anomalous features in fault-zone seismograms produced by events not necessarily in the fault may be referred to generally as fault-zone-related site effects. The oscillatory shear wave trains after the direct S arrival in these seismograms are analysed as trapped waves propagating in a low-velocity fault-zone layer. The time difference between the S arrival and trapped waves group does not grow systematically with increasing source-receiver separation along the fault. These observations imply that the trapping of seismic energy in the Karadere-Duzce rupture zone is generated by a shallow fault-zone layer. Traveltime analysis and synthetic waveform modelling indicate that the depth of the trapping structure is approximately 3-4 km. The synthetic waveform modelling indicates further that the shallow trapping structure has effective waveguide properties consisting of thickness of the order of 100 m, a velocity decrease relative to the surrounding rock of approximately 50 per cent and an S-wave quality factor of 10-15. The results are supported by large 2-D and 3-D parameter space studies and are compatible with recent analyses of trapped waves in a number of other faults and rupture zones. The inferred shallow trapping structure is likely to be a common structural element of fault zones and may correspond to the top part of a flower-type structure. The motion amplification associated with fault-zone-related site effects increases the seismic shaking hazard near fault-zone structures. The effect may be significant since the volume of sources capable of generating motion amplification in shallow trapping structures is large.
Abstract. The coasts of Turkey have been hit by tsunamis in the past. The first national earthquake-tsunami catalogues were compiled in the early 1980s while the most up-to-date tsunami catalogues are mainly the products of recent European projects. The EU projects GITEC and GITEC-TWO (Genesis and Impact of Tsunamis on the European Coasts) and TRANSFER (Tsunami Risk ANd Strategies For the European Region) have added important contributions in establishing and developing unified criteria for tsunami parameterisation, standards for the quality of the data, the data format and the database general architecture. On the basis of these new aspects and based on recent marine geophysical data, tsunamigenic earthquakes, tsunami intensities and their reliability have been revised. The current version of the database contains 134 events, most of which have affected the Turkish coasts seriously during the last 3500 years. The reliability index of 76 events was "probable" and "definite", so that they could be used for assessment of the risk along the Turkish coastal region and for implementation of prevention policies.
From a global perspective, the universality of gender-related societal issues is particularly significant. Although gender inequality is considered a sociological problem, the large number of female victims in disasters warrants an assessment of disaster management sciences. In this article, related concepts are discussed based on their relevance sociologically and in disaster management to develop a common terminology and examine this complex topic, which is rooted in different social profiles and anthropological heterogeneity throughout the world. A brief history is discussed, and significant examples are provided from different disasters in Turkey to illustrate why a woman-oriented approach should be adopted when evaluating concepts of gender inequality. Observations of disasters have shown that it is important to apply international standards (humanitarian charter and minimum disaster response standards), especially during periods of response and rehabilitation. Relevant factors related to gender should be included in these standards, such as women’s health and hygiene, which will be discussed in more detail. A woman-based approach is designed in relation to two aspects: risks and resources. Thus, gender-sensitive methods of mitigating and preventing disasters are provided. The main purpose of the article is to contribute to the development of a universal culture that prioritizes gender in disaster management.
The disastrous 1999 earthquakes in Turkey have spurred the international community to study the geometry and behavior of the North Anatolian Fault (NAF) beneath the Marmara Sea. While the area is considered mature for a large earthquake, the detailed fault geometry below the Marmara Sea is uncertain, and this prevents a realistic assessment of seismic hazards in the highly‐populated region close to Istanbul. Two geological/geophysical surveys were recently conducted in the Marmara Sea: the first in November 2000 with the R/V Odin Finder, and the second in June 2001 with the R/V CNR‐Urania. Both were sponsored and organized by the Institute of Marine Geology of the Italian National Research Council (CNR), in cooperation with the Turkish Council for Scientific and Technical Research (TUBITAK) and the Lamont‐Doherty Earth Observatory of Columbia University Multi‐beam bathymetry, multi‐channel seismic reflection profiling, magnetometry high‐resolution CHIRP sub‐bottom profiling, and bottom imaging were carried out with a remotely operated vehicle (ROV). Over 60 gravity and piston cores were collected.
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