Site selection for hazardous wastes: A case study from the GAP area, Turkey

The increase in the popularity of using environmental design criteria in town and country planning has brought about the need to fully identify the principles to determine the best location of hazardous wastes to be landfilled. This environmental management issue has received considerable attention because of its applications in urban and rural infrastructure planning, industrial development planning as well as health, housing, transportation and agricultural schemes. This paper explains a method to determine how to locate suitable sites for hazardous waste landfilling area by using the site screening study. It demonstrates how the criteria such as geology, topography, land use, climate, earthquake and other related factors can be introduced into the overlayer technique to determine the suitable site selection in a region. The research was undertaken in the Southeastern Anatolia Project (known as GAP in Turkey) region where identifying the land resources is crucial for agricultural and water management purposes. The paper also explains the validity of the method employed on the site selection process for hazardous wastes. The introduced method may enable more accurate design procedure for planning in environmental management in future.     

Paleoseismology of the Palu–Lake Hazar segment of the East Anatolian Fault Zone, Turkey

The East Anatolian Fault Zone (EAFZ) is among the most important active continental transform fault zones in the world as testified by major historical and minor instrumental seismicity. The first paleoseismological exploratory trenching study on the EAFZ was done on the Palu–Lake Hazar segment (PLHS), which is one of the six segments forming the fault zone, in order to determine its past activity and to assess its earthquake hazard.The results of trenching indicate that the latest surface rupturing earthquakes on this segment may be the Ms=7.1+ 1874 and Ms=6.7 1875 events, and there were other destructive earthquakes prior to these events. The recurrence interval for a surface rupturing large (M>7) earthquake is estimated as minimum 100±35 and maximum 360 years. Estimates for the maximum possible paleoearthquake magnitude are (Mw) 7.1–7.7 for the Palu–Lake Hazar segment based on empirical magnitude fault rupture relations.An alluvial fan dated 14,475–15,255 cal years BP as well as another similar age fan with an abandoned stream channel on it are offset in a left-lateral sense 175 and 160.5 m, respectively, indicating an average slip rate of 11 mm/year. Because 127 years have elapsed since the last surface rupturing event, this slip rate suggests that 1.4 m of left-lateral strain has accumulated along the segment, ignoring possible creep effects, folding and other inelastic deformation. A 2.5 Ma age for the start of left-lateral movement on the segment, and in turn the EAFZ, is consistent with a slip rate of 11 mm/year and a previously reported 27 km total left-lateral offset. The cumulative 5–6 mm/year vertical slip rate near Lake Hazar suggests a possible age of 148–178 ka for the lake. Our trenching results indicate also that a significant fraction of the slip across the EAFZ zone is likely to be accommodated seismically. The present seismic quiescence compared with the past activity (paleoseismic and historic) indicate that the EAFZ may be “locked” and accumulating elastic strain energy but could move in the near future.     

Nonlinear shear mass participation factor (rd) for cyclic shear stress ratio evaluation

Most methods for assessment of in situ seismic soil liquefaction potential require evaluation of the earthquake-induced cyclic shear stress ratio (CSR). Estimates of the in situ CSR can be developed directly, using dynamic response analyses, but it is common in ‘simplified’ analysis methods to develop estimates of the in situ CSR using empirical relationships. Unfortunately, the most widely used existing empirical relationships are based on limited response analyses and do not take full advantage of current knowledge of factors affecting this response problem. As a result, they are both biased and unnecessarily imprecise. This paper presents the results of a relatively comprehensive suite of site response studies (2153 site response analyses), performed using carefully selected suites of site conditions and input time histories, to provide an improved basis for development of estimates of in situ CSR using the r_d-approach. The resulting empirical correlations, developed using the Bayesian updating method, provide a much improved basis for simplified empirical evaluation of CSR as a function of (1) depth; (2) earthquake magnitude; (3) intensity of shaking; and (4) site stiffness.     

Seismically induced landslide at Degirmendere Nose, Izmit Bay during Kocaeli (Izmit)-Turkey earthquake

This paper presents a study on the analyses of seismically induced landslide at Degirmendere Nose during the 1999 Kocaeli (Izmit)-Turkey earthquake. The paper discusses: (1) observed ground deformations and displacements after the earthquake, (2) the results of field investigations by means of borings and in situ index tests including standard penetration tests, static cone penetration tests (CPT) and piezocone tests, (3) analyses of observed landslide mechanisms by a suite of methods and (4) potential effects of soil liquefaction rupture on the observed landslide mechanism.     

Assessment of geo-environmental properties depressing urban development with GIS: a case study of Kozlu settlement,Turkey

Kozlu is a mining town only 5 km away from the main city of Zonguldak and initially was not favored for settlement due to its rugged and hilly topography. However, along with hard coal production in large quantities throughout the years came the industrialization at its full speed with plenty job opportunities which then gave rise to intense population in the region where there were only a few sheds and slums just a century ago. Workers migrating to Kozlu in thousands needed dwellings to live in, but the law, so-called the Coal Basin Restrictions Law which came in effect in 1910, hindered the implementation of zoning plans. Planned housing was not possible in the region not until the abolishment of the law in 1986. During these 76 years, the settlement in the area mostly by the mining and industry workers was carried out without proper zoning plans, usually on demand basis. Today because of this unplanned housing and harsh topography, the Kozlu settlement area (KSA) has a history of being attraction point for many natural and man-made disasters which can be summarized as are topography, geological and carstic structure, mining activities and mass movements. In this study, a settlement suitability map is produced for the study area using a geographic information system. The map produced is designated into four settlement suitability zones, namely suitable to settlement, slightly suitable to settlement, suitable to settlement with precautions and unsuitable to settlement. It clearly shows that 24.73% of the study area lies in suitable and slightly suitable to settlement areas while the bulky rest pertains to suitable to settlement with precautions and unsuitable to settlement. The latest studies show that the 37.5% of the buildings and houses in the KSA are situated on the lithologic units identified as hydrogeological permeable and semipermeable, 7.8% on carstic caverns and a hefty rate of 47.6% on the surfaces deformed by mining-induced subsidence. Therefore, it is needless to claim that the administrators of Kozlu should promptly develop a settlement plan for the welfare of the city.     

Chorus observations by the Polar spacecraft near the mid-altitude cusp

Observations of whistler-mode emission, including chorus, were made frequently by mid-altitude satellites such as Polar. In this study we examine an example of such emission when the high-frequency waveform receiver on board Polar was operating allowing direction-finding and polarization measurements in the low-altitude cusp. The results reveal at least two and possibly three distinct groups of narrow-banded chorus emission with a primary source region at the magnetic equator. The groups include emission propagating near the resonance cone angle, emission propagating along a density duct, and possibly emission reflected from the low-altitude cusp. The results indicate that the mid- and low-altitude cusp, perhaps unlike the high-altitude cusp, is not a significant source of narrowband chorus emission.     

A satellite based assessment of the impact of urban expansion around a lagoon

This paper examines the coastal regional trends in urbanization processes using remotely sensed images around the Kucukcekmece Lagoon as a case study, located in the western part of Istanbul, Turkey. Throughout the examination process, the coastline changes are determined for a long-term period. To achieve this goal, post-classification comparison method is applied to the CORONA and LANDSAT TM satellite images of 1963, 1987 and 2005. In order to identify the land use changes, common landscape structures in the region were distinguished as water, green and open land, urban and industrial areas. Due to the mix up of land-cover types between urban and industrial areas, the classified images are integrated with geographic information system data obtained from visual interpretation of the enhanced images and auxiliary data sets. The results of the change analyses in coastal region showed that important alterations are taking place in the area due to the unplanned urban and industrial expansions that has irreversibly changed the physical features of the Kucukcekmece Lagoon. According to image classification results, the urban land use area increased from 2 % oftotal area in 1963 to 38 % in 1987 and 46 % in 2005, most of which converted from agricultural and greenlands. At the same time, the ecological impact of the loss of specific land covers is highlighted based on the results of the land use changes and the previous scientific applications. Furthermore, some recommendations are given to planners, decision makers and politicians to maintain the sustainable coastal ecosystem management.     

Freeze-thaw performance of chemically stabilized natural and recycled highway materials

This article provides an overview of several previous studies that investigated the stiffness and strength performance of chemically stabilized roadway materials under winter conditions (freeze-thaw cycling). The objective of this research was to understand the behavior of different materials stabilized with different type of binders when they were subjected to freeze-thaw cycling. Nine different materials including natural soils (organic soil, clay, silt, sand, and road surface gravel), reclaimed pavement material, and recycled asphalt pavement stabilized with nine different binders (five different fly ashes, lime, cement, lime kiln dust, cement kiln dust) were discussed. This article investigated how the volume, resilient modulus and unconfined compressive strength of soils/materials stabilized with different binders change in response to freeze-thaw cycling. Overall, the review results indicate that the stiffness and strength of all stabilized materials decrease somewhat with freeze-thaw cycling. However, the reduced strength and stiffness of stabilized materials after freeze-thaw cycling was still higher than that of unstabilized-unfrozen original soils and materials. In addition, materials stabilized with cement kiln dust provided the best performance against freeze-thaw cycling.     

Comparative evaluation of freeze and thaw effect on strength of BEICP-stabilized silty sands and cement- and fly ash-stabilized soils

Acta Geotechnica - This paper addresses a soil bio-stabilization technique using bacterial enzyme-induced calcium carbonate precipitation (BEICP) as an alternative to previous conventional methods...