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51.
A geohazard reconnaissance study based on geoscientific information for development needs of the western region of Istanbul (Turkey) 总被引:1,自引:0,他引:1
Tamer Y. Duman Tolga Can Reşat Ulusay Mustafa Keçer Omer Emre Serafettin Ateş Ibrahim Gedik 《Environmental Geology》2005,48(7):871-888
The role of geoenvironmental information is becoming increasingly important as legislative changes have forced developers
and planning authorities to consider more implications and impact on the environment of large-scale development initiatives.
Therefore, integration of surface and subsurface geoscientific information for development needs has prime importance and
provides a means of identifying potential problems and opportunities at an early stage in any planned development. However,
from the experience of recent natural disasters, it is evident that this was not case the taken into consideration in many
countries. In addition to thousands of casualties, many urbanized areas, industrial districts and large-scale engineering
structures suffered severe damages from the natural hazards due to many reasons including the lack of preliminary engineering
geological maps and zoning maps of the settlement areas. Turkey is one of the countries which is exposed to natural hazards
such as earthquakes, landslides and floods. In particular, the devastating 1999 Kocaeli earthquake, which affected the Marmara
Region of Turkey, focused the attention on densely urbanized and industrialized metropolitan areas such as Istanbul. The rapid
growth of Istanbul, particularly towards west with minimal geoscientific information resulted in an overwhelming pressure
on the natural environment. In addition, a large earthquake, which is expected to occur in the Marmara Sea within the next
30 years, also pose a threat to the city and its surroundings. In this study, on the basis of the geological, geomorphological
and geophysical reconnaissance study, an integrated geoscientific data were collected from the western region of Istanbul
and evaluated for geohazards. The paper focuses on the geological and geomorphological aspects that control the occurrence
of some geohazards such as earthquake-induced liquefaction, landslides and flooding. In this context, the geological map of
the region was revised and Quaternary deposits were classified into 11 units, in detail. Liquefaction-prone areas were evaluated
by using geomorphological criteria based on field investigation, by the examination of the available records from 88 boreholes
drilled on recent deposits and by the data from resistivity profiles. The landslides within the region were classified according
to their type, relative depth and activity. In addition, fluvial and marine flood-prone areas were also delimited within the
region. Finally, a series of maps such as landslide inventory maps, and maps showing liquefaction- and flood-prone areas were
produced with the aid of Geographic Information Systems (GIS) to assist in designing further detailed site investigations
and to reduce costs by ensuring a more focused approach to strategic planning and site selection. 相似文献
52.
Comparison of TRMM-based flood indices for Gaziantep,Turkey 总被引:1,自引:0,他引:1
Floods are the most common natural disasters threatening the welfare of humanity. Gaziantep, a city located in a semi-arid region of Turkey, is occasionally flooded, and in May 2014, a flood not only caused property damage, but also resulted in the death of a lady who became trapped in flood waters. The fatality and property damage of flash floods arise from the limited response time for remediation. Despite improvements in numerical weather predictions, forecasting flash floods is not easy. Due to its frequent observations, Tropical Rainfall Measuring Mission (TRMM) Multi-Satellite Precipitation Analysis (TMPA) real-time (RT) 3B42RT data are tested for Gaziantep flood predictions in this study. During TRMM era, six floods occurred in Gaziantep. Three-hourly 3B42RT data covering the 2000- to 2014-year period indicated high rain rates during months in which floods were observed. Also daily variation of rainfall was well represented. High-intensity rain (HIR), cumulative distribution functions (CDF) and Gaziantep Flood Index (GAFI) indices are developed for flood characterization. HIR, calculated as 10 mm/h, detected October and December of 2010 floods. CDFs with 99, 98.5, 95 and 91.3% indicated 4 floods occurred in August 2005, June 2007, October 2010 and December 2010, respectively. GAFI was able to detect 4 out of 6 occurrences (August 2005, June 2007, October 2010 and December 2010) as values ranging from 1 to 2.63 are selected for monthly precipitation. In the missed occurrence, 3B42RT did not indicate any rainfall. Although only rain rates are used in flood characterization, the results are promising, and the simplicity of the methodology favors its usage. Also, methodology can easily be implemented to TRMM following missions such as Global Precipitation Measurement Mission. 相似文献