Soil and sediment quality and composition as factors in the distribution of damage at the December 26, 2003, Bam area earthquake in SE Iran (M s = 6.6)

Background, aim, and scope

The rapid growth of the world’s population over the past few decades has led to a concentration of people, buildings, and infrastructure in urban areas. The tendency of urban areas to develop in sedimentary valleys has increased their vulnerability to earthquakes due to the presence of soft soil and sediment. Several earthquakes have clearly demonstrated that local soil and sediment conditions can have a significant influence on earthquake-induced ground motion and damage pattern, respectively. Many studies confirm the relationship between site effect and ground motion (Borcherdt in Bull Seismol Soc Am 60:29–61, 1970; Bouckovalas et al. in Geotech Geolog Eng (Historical Archive) 14(2):111–128, 1996; Fäh et al. in Seismology 1:87–10, 1997; Atakan et al. in Nat Hazards 15(2–3):139–164, 1997; Christaras et al. in Geodynamics 26(2–4):393–411, 1998; Raptakis et al. in Bull Earthquake Eng 2(3):285–301, 2004a; Raptakis et al. in Soil Dyn Earthq Eng 25:871–887, 2005; Marka et al. in Pure Appl Geophys 158:2349–2367, 2001; Marka et al. in Soil Dyn Earthq Eng 25(4):303–315, 2005; Importa et al. in Seismology 9(2):191–210, 2005; Tyagunov et al. in Nat Hazards 38:199–214, 2006; Lombardo et al. in Nat Hazards 38:339–354, 2006; Rayhani et al. in Geotech Geol Eng 21(1):91–100, 2008). In order to classify the suitability of the soil and subsurface sediment units for urban planning and compare their mechanical behavior with the non-uniform damage observed in the 2003 earthquake, we performed some geotechnical and geophysical analyses of soil and sediment samples collected from different locations in Bam City.

Methodology

Geophysical and geotechnical properties, such as grain size distribution, sorting, plasticity, Poison’s ratio, shear strength, compression index, permeability, and P and S wave velocities in soil and subsurface sediments, were measured. Maps (in GIS environment) and cross-sections were prepared for the study area.

Results

According to our observations, a great number of buildings were damaged in areas of the city where silty and clayey soils dominate, presenting very low permeability, low wave velocity together with high plasticity, and compressibility. In the study area, we recognized eight sediment types. Shear wave propagation velocities allowed for the identification of four seismic layers referred to as the surface layer, second layer, and third layer and seismic bedrock. We found that the damages observed in the Bam area were related to the physical and mechanical properties of the soil and subsurface sediment units. We also found that the soil thickness that was estimated by geophysical surveying shows a direct relationship with damage rate observations. Furthermore, we observed that landslide and qanat collapses have occurred in some areas where sand and silty sand soils and subsurface sediments dominate.

Discussion

The distribution of the damage shows a microzonation that is very serious in some points in the city along the main fault, especially where it is located on thick, fine, medium, and loose soil and sediments. In general, there is a discernable west to east increase in the damage across the city. The average level of destruction for the entire city was ~75%, while the eastern part of the city locally reached 100% destruction level. The major factors that influenced the damage and destruction in the Bam region were the distance of a given site from the seismic source, the quality of foundation soil and subsurface sediment, and the type of building. The Bam earthquake occurred on a single fault network comprising the Bam and Arg-e-Bam faults (Funning et al. in J Geophys Res 100(B09406):1–23, 2005). The sediments and soil of the area (unconsolidated silty sand and sandy gravel) belong to braided fluvial and alluvial facies. Most of the buildings near the epicenter area were old and constructed of mud bricks using mud cement.

Recommendations and perspectives

A combined sedimentological, geological, neotectonic, geotechnical, paleoseismological, and geophysical investigation in urban areas (especially in alluvial valleys) will give the detailed knowledge of the subsurface structure required for the accurate and precise seismic hazard assessments needed for effective earthquake protection planning. This paper shows that for the Bam situation, sedimentological data are required to provide an interpretive context for the geophysical data.     

N2O, NH3 and NOx Emissions as a Function of Urea Granule Size and Soil Type Under Aerobic Conditions

We examined the influence of various urea granule sizes (< 2, 7.0, 9.9 and 12.7 mm) applied into a silt loam soil (experiment 1) and soil types (sandy, silt and clay loam) treated with the largest granule (experiment 2) on gaseous N loss (except N₂) at field capacity. The prilled urea (PU) was mixed into the soil whereas the urea granules were point-placed at a 5.0-cm depth. For experiment 1, N₂O emission was enhanced with increasing granule size, ranging from 0.17–0.50% of the added N during the 45-day incubation period. In the case of experiment 2, the sandy loam soil (0.59%) behaved similarly with the silt loam (0.53%) but both showed remarkably lower emissions than were found for the clay loam soil (2.61%). Both nitrification and N₂O emissions were delayed by several days with increasing granule size, and the latter was influenced by mineral N, soil water and pH. By contrast, the NH₃ volatilization decreased with increasing granule size, implying the inhibition of urease activity by urea concentration gradients. Considering both experimental results, the NH₃ loss was highest for the PU-treated (1.73%) and the larger granules regardless of soil type did not emit more than 0.27% of the added N over 22 days, possibly because the high concentrations of either mineral N or NH₄ ⁺ in the soil surface layer (0–2.5 cm) and the high H₊ buffering capacity might regulate the NH₃ emission. Similar to the pattern of NH₃ loss, NO_x emission was noticeably higher for the PU-treated soil (0.97%) than for the larger granule sizes (0.09–0.29%), which were the highest for the sandy and clay loam soils. Positional differences in the concentration of mineral N and nitrification also influenced the NO_x emission. As such, total NH₃ loss was proportional to total NO_x emission, indicating similar influence of soil and environmental conditions on both. Pooled total N₂O, NH₃ and NO_x emission data suggest that the PU-treated soil could induce greater gaseous N loss over larger urea granules, largely in the form of NH₃ and NO_x emissions, whereas a similar increase with the largest granule size was mainly due to the total N₂O flux.     

Improved growth of salinity-stressed citrus after inoculation with mycorrhizal fungi

The present investigation was conducted during 2006 and 2007 growing seasons in order to study the effects of different salinity levels on the growth and chemical composition of sour orange and Volkamer lemon rootstocks. Besides, this research was also undertaken to elucidate the efficiency of mycorrhizal colonization on controlling the various hazards accompanying salinity stress. One-year-old sour orange and Volkamer lemon rootstocks were kept in a glasshouse and irrigated with control (non-saline), 1500 ppm, 3000 ppm and 4500 ppm of salinity levels. Salinity decreased arbuscular mycorrhizal (AM) colonization. In both the AM and non AM, leaf area, trunk cross-sectional area, total, top, leaf and root dry weights were decreased under salinity. The plants inoculated with the AM fungus had significantly higher growth parameters compared to the non-inoculated plants. Increasing the salinity level tended to increase the concentrations of leaf Na, N, Ca and Cl while P, K, Mg, Fe, Mn, Zn and Cu decreased. On the contrary, inoculating the seedlings with AM tended to increase the levels of P, K, Mg and Zn. Whereas leaf N, Ca and Na of inoculated seedlings was significantly lower than that of un-inoculated ones. Leaf Cl, Fe, Mn and Cu contents did not statistically vary in this concern.     

Analysis and effect of water sources used as diluents on Newcastle disease vaccine efficacy in chickens in the Sudan

Samples of artesian well, shallow well, surface water, tap water, and bottled water were collected from different areas in Khartoum; these were chemically analyzed and used as diluents to vaccinate chicks against Newcastle disease. Immune response in vaccinated chicks, as measured by the hemagglutination inhibition test, was significantly better in birds which received the vaccine diluted in bottled water followed by those vaccinated using tap water. It appears that water with low turbidity and total dissolved solids were the best water for vaccine dilution. The order of preference of water source, according to this study was bottled water, tap water, shallow well water, artesian well water, and finally surface water.     

Changes in the quality of Nile water in Egypt during the twenty-five years, 1954–1979

Summary The study describes the variation in the chemical constituents of the Nile water at Giza, through the twenty-five years from 1954 to 1979 i.e., before and after the construction of the High Dam at Aswan.The total soluble salt content increased significantly by 29% after the construction of the High Dam, mainly due to the seepage of drainage water from the cultivated land of the Nile Valley. The SO4 _inf4 ^– , Cl^–, K⁺, Na⁺ & Mg⁺⁺ content increased significantly during the period of study, while the increase in pH values, HCO _inf3 ^– and Ca⁺⁺ contents was not significant.The suspended matter content decreased significantly by 94% from 1964 to 1979 due to the effect of the High Dam. The increase in silica content was significant while the decrease in oxygen content was not significant. No obvious variations were detected in chloride content, total alkalinity and total hardness during the study period.According to the ionic coefficients ratios and the geochemical classification, Nile water currently can be evaluated for irrigation purposes as falling within the class excellent — good and highly satisfactory for domestic purposes.     

Distribution of major elements and trace metals as indicators of technosolisation of urban and suburban soils

Purpose

Can geochemical characteristics indicate the human impact on soil formation (technosolisation) for urban and suburban soils? This question is assessed for the city of Marrakech located in one of the main agricultural areas of Morocco and characterized by a very rapid rate of expansion. The aim of this work is to assess geochemical properties of surface horizons of urban and suburban soils and to compare them with land use types.

Materials and methods

Fifty-eight surface soil samples were collected in different sectors of the city with different land use histories. As land use can be defined as the human use of land, these sampling sites were selected according to the current human activity (e.g., residential districts, agriculture, market-gardening, traditional, or industrial activities) and according to the superposition of the land use over time. All samples were air-dried, disaggregated, homogenized, and then sieved through a 2-mm mesh. Major elements and trace metals were measured in the soil using X-ray fluorescence spectroscopy. For technical limits, Cd was measured using atomic adsorption spectrometry.

Results and discussion

Urban and suburban soils of Marrakech present generally similar geochemical compositions for many elements. Siliceous (SiO₂) compounds related to the parent material are dominant in these soils. However, the significant concentrations of P₂O₅ and CaO, measured in some of the urban soils studied, can be attributed to anthropogenic inputs of phosphorus (P) and technic materials, mainly building materials composed of cement and gypsum (plaster). Soils collected from agricultural areas irrigated with urban wastewater and soils developed on rubbish dumps are the most contaminated by metals (e.g., Cu, Zn, and Pb). Therefore, the distribution of major and trace elements in soils underlines the considerable impact of urban land uses.

Conclusions

Human activities determine the type of land use, impact the urban environment, and cause a wide spatial diversity of soil quality. The urban and suburban soils of Marrakech contain similar major element distributions except for strongly anthropised soils (soils developed on rubbish dumps and agricultural soils irrigated with urban wastewater). Unlike major elements, trace elements present systematically significantly higher concentrations in urban soils than those measured in control soils. In these conditions, the highest concentrations exceed international clean-up standards and are correlated with land use type. Phosphorus, Ca, and several heavy metals are proposed as indicators of human impacts on soil characteristics in urban and suburban environments.     

Increase in NAD(P)H‐dependent generation of active oxygen species and changes in lipid composition of microsomes isolated from roots of zinc‐deficient bean plants

The role of zinc (Zn) in maintaining the structural and functional integrity of plant membranes was investigated in the present work. The relationship between the activity of NAD(P)H oxidases generating active oxygen species and changes in lipid composition and peroxidation was evaluated in microsomal membrane vesicles isolated from roots of Zn‐defícient bean (Phaseolus vulgaris L., cv. Bobis) plants. Zinc content of bean root microsomal membranes was decreased by about 30% by Zn deficiency. Microsomes isolated from roots of Zn‐deficient plants showed higher rates of NAD(P)H oxidation and NAD(P)H‐dependent O₂ ^‐ generation than Zn‐sufficient roots. Microsomal O₂ ^‐ consumption, measured in the presence of pyridine nucleotides, was also considerably enhanced by Zn deficiency. This latter activity was greatly stimulated by Fe(III)EDTA, while inhibited by Superoxide dismutase (SOD) and catalase, indicating that active oxygen species were produced during the oxygen consuming enzyme reaction. Zinc deficiency caused a decline in microsomal phospholipid (PL) content. In addition, saturated fatty acids were present at a higher proportion than unsaturated fatty acids in microsomes from Zn‐deficient roots. Sterol content of microsomal vesicles was also modified by Zn deficiency, which led to an increase in the planar sterol campesterol and a concomitant decrease in stigmasterol and sitosterol content. NADPH‐dependent lipid peroxidation, directly measured in microsomal vesicles as malondialdehyde (MDA) production, was slightly enhanced by Zn deficiency. These results support the idea that Zn deficiency determines an enhanced generation of harmful oxygen species by membrane‐associated enzymes and show that this activity can be more pronounced in the presence of iron (Fe), which accumulates in Zn‐deficient tissues. The relationship between the occurrence of this phenomenon and the changes in membrane lipid profile is discussed.     

EFFECTS OF GYPSUM ENHANCED COMPOSTS ON YIELDS AND MINERAL COMPOSITIONS OF BROCCOLI AND TALL FESCUE

Gypsum (CaSO₄·2H₂O) addition during composting of manure or biosolids can reduce ammonia nitrogen losses and represents a new method for controlling odors. Additional work is needed, however, to test the ability of the gypsum-containing composts to support plant growth and affect uptake of nutrients and heavy metals. A field study using broccoli (Brassica oleracea L. var. italica) and a growth chamber study using tall fescue (Festuca arundinacea) were conducted by application of composts at 10 Mg ha^?1 for broccoli and 10 and 25 Mg ha^?1 for tall fescue. Compared to composts without gypsum, at 10 Mg ha^?1, gypsum composts significantly increased or had a strong trend to increase yields of broccoli and tall fescue. Gypsum composts affected concentrations of nutrient elements but did not increase concentrations of environmental concern elements in broccoli flowers and tall fescue tissue. Thus gypsum composts can be safely applied to soils to enhance crop growth.     

Effects of seed priming with plant growth-promoting rhizobacteria on wheat yield and soil properties under contrasting soils

In the present investigation, different strains of Plant growth-promoting rhizobacteria (PGPR), namely Bacillus megaterium, Pseudomonas fluorescens and Bacillus subtilis were evaluated for their growth-promoting effects on wheat as well as on soil properties under field conditions at two different sites having sandy loam and silt loam type of soils. PGPR strains were evaluated either singly or in consortia. Amongst all the treatments, wheat inoculated with consortia was found most effective as it increased grain yield up to 53% over control in silt loam soil, whereas, corresponding effects in sandy loam soil were less pronounced as an increase of 31% was observed in corresponding treatments, respectively. Enhanced effects on soil properties were also more intense in silt loam as there was an increase of 205% organic matter as against sandy loam soil where this value was 110%.