فهرست مطالب

Journal of Seismology and Earthquake Engineering
Volume:9 Issue: 1, Spring and Summer 2007

  • تاریخ انتشار: 1387/02/10
  • تعداد عناوین: 7
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  • B. Grecu, M. Radulian, N. Mandrescu, G. F. Panza Page 1
    The main issue of this paper is to show that contrary to many examples of monitored strong earthquakes in different urban areas, the intensity and spectral characteristics of the strong ground motion induced in Bucharest area, by Vrancea intermediate-depth earthquakes, is controlled by the coupled source-site properties rather than by the local site conditions alone. Our results have important implications on the strategy to follow when assessing the seismic microzoning for Bucharest city: we recommend the application of deterministic approaches rather than empirical techniques, like H/V spectral ratios. However, when applied to noise data, the H/V spectral technique succeeds to reproduce the predominant frequency response characteristic for the sedimentary cover beneath the city and the relatively uniform distribution of this structure over the city area. The same technique is clearly inadequate when small earthquakes are considered and our results strongly disagree with any strategy of extrapolation from small and moderate earthquakes to strong earthquakes for microzoning purposes.
  • A. Ahmed, M. L. Sharma, A. Sharma Page 15
    A phase picking algorithm has been developed for P-wave arrival detection and picking on a 3-component broadband seismogram. The algorithm is based on Wavelet Transform, Akaike Information Criteria (AIC) picker and voting mechanism. The mathematical functions have been used to cut up data into different frequency components and each component with a resolution matched to its scale is studied. Continuous Wavelet Transform (CWT) has been applied to pre-filtered 3-component broadband seismograms to compute scales of interest. Wavelet coefficients have been calculated in a sliding time window and AIC picker is applied to these coefficients. Consistency of 3 components picks is the primary criteria of phase detection. Further, for phase picking, AIC picker is applied on the filtered seismogram in the same time window where phase is detected. The comparison of the present algorithm has been checked with the time domain automatic phase pickers and manual picks by seismologists. The algorithm has been tested on regional earthquake data acquired through deployment of broadband seismological station in Garhwal Kumaon Himalayan region and shows a good agreement between analyst picks and auto picks.
  • Reza Tarinejad, Mohammad T. Ahmadi, and Naser Khaji Page 25
    Topographic conditions play an important role on the modification of seismic ground motion. Therefore, their effects may become crucial in the selection or simulation of ground motion for use in structural seismic response analysis. In this research, topography effects of canyon sites are analyzed using a three-dimensional boundary element procedure. The multi-domain boundary element method proposed by Ahmad and Banerjee is used for three-dimensional cases with good accuracy. Effects of model parameters (free-field and canyon lengths) are well accounted for ensuring accurate results. It is shown that the free-field (both side of the canyon cross-section) length is less influential than the canyon length. Some general rules for the three-dimensional boundary element modeling of wave scattering problem are proposed. In addition, effects of different wave parameters (frequency and direction), material properties (damping ratio and poisson''s ratio) and canyon geometry are investigated.It is demonstrated that the effect of canyon shape and canyon depth on the topographic amplification is frequency dependent. Deep canyon (semi-circular canyon) induces larger amplification effect than shallow canyon (semi-elliptical canyon) in different frequencies.
  • A. Mohebkhah, A. A. Tasnimi, H. A. Moghadam Page 39
    Nonlinear numerical modeling of masonry-infilled frames is one of the most complicated problems in structural engineering field. This complexity is attributed to the existence of joints as the major source of weakness and material nonlinearities as well as the infill-frame interaction. Although there are many numerical studies on micro-modeling of solid masonry-infilled steel frames, however, few researches have been conducted on infilled frames with openings. This paper develops a two dimensional numerical model using the specialized discrete element software UDEC (2004) for the nonlinear static analysis of masonry-infilled steel frames with openings. This model is employed to investigate the effect of the size of central window openings on the lateral strength and stiffness of infilled steel frames. Furthermore, the efficient three-strut macro-model proposed for pushover analysis of solid infilled frames is modified for those having central window openings. It was found that the modified three-strut (MTS) model can be used confidently to predict both the stiffness and capacity of such frames up to failure. This model can be easily employed in seismic vulnerability analysis of existing steel frames having infill panels with central window openings.
  • David Alexander Page 49
    This paper reviews contemporary trends in the management of the crisis phase of disasters. It charts the recent history of emergency preparedness in the light of a basic distinction between civil defence and civil protection. As the former has metamorphosed into homeland security and the latter into civil contingencies management، so a distinction has grown between devolved and centralized management of disasters. This has been accompanied by differences in the strategies employed to bring relief to stricken populations، including the extent to which military and paramilitary forces are involved. The question of devolved versus centralized emergency management is considered in the light of its impact on welfare. The paper then reviews some aspects of the management of Hurricane Katrina in New Orleans in August-September 2005. It seems reasonable to conclude that symbolic aspects of the media and political response tended to provide impetus to discrimination in the provision of aid. In economic terms، disaster involves a complex process of negotiating for resources، in which the marginalized sections of society are almost automatically disadvantaged. The solution lies in making emergency preparedness more democratic، which is a major challenge for the present century. The article ends by establishing ten principles for fair and democratic civil protection.
  • Louise K. Comfort Page 61
    The recurring pattern of failed governmental actions in response to major disasters compels a re-examination of the traditional organizational framework of command-and-control that has served as the basis for disaster planning and response actions in most nations of the world. The contrast between the top-down hierarchical control that is presumed in national emergency plans and the need for flexibility required in effective operations in rapidly changing disaster environments requires a fresh approach to emergency planning and action. This article focuses on the role of cognition of risk as the triggering action that leads to effective communication, coordination, and emerging collective control as a community learns to manage risk more effectively in collaboration with other organizations and wider jurisdictional authorities.
  • M. R. Ghayamghamian, Tetsuo Tobita, Susumu Iai, Gi, Cheon Kang Page 73
    The damage survey of the Niigata-ken Chuetsu-Oki, Japan earthquake (MJMA = 6.8) of July 16, 2007 was conducted by the reconnaissance team of Disaster Prevention Research Institute (DPRI), Kyoto university. The area with dimension of 24 km x 19 km is investigated by the reconnaissance team. This paper reports the seismological aspects and observed geotechnical and structural damage during the damage survey in the area. The landslides, liquefaction and ground settlements were the most important geotechnical features that caused serious damage to the lifelines and buildings. Especially, landslides caused major damage to the railways and roads. The building damage survey was conducted around Kashiwazaki city hall where the K-net strong motion station was located. The damage to the buildings was classified as D2 or D3 within 100m around the city hall. Meanwhile, the collapsed wooden houses (D6 Grade) were mostly concentrated in Higashi Honmachi street situated in 280 m south of city hall. Most of the wooden house, concrete block fences and tomb stones seem to have collapsed in the northwest-southeast direction falling to the east as to the west. This direction was found to be in the direction of slip on the fault.