JOURNAL OF NATURAL ENVIRONMENT HAZARDS
Year:2018 | Volume:6 | Issue:14 |Papers Count:10

The phenomenon of dust due to recent drought has caused undesirable biological effects and great damages in agricultural, industrial, transportation and communication systems. Geochemical studies are important to determine the possible source of dust, geoenvironmental characteristics of elements and the role of their role in environmental pollution. Two area sources were identified for the incoming dust to the country by investigation of previous studies in June 2012 and 12 samples of dust in Abadan and Ahvaz were collected and their mineralogy and elemental analysis were analyzed. The results of mineralogy showed that carbonates (calcite and dolomite) have the source of feldspar with a source of continental and sedimentary. Lagoons and dried lakes are a source of clay minerals (chlorite and illite) and evaporate (halite and gypsum) and probably kaolinite originated from smectite and feldspar group. In regard to the results of the geochemistry of some heavy metals and radioactive indicate that most of them have an anthropogenic origin (Uranium, Cadmium, and Sulfur have high enrichment and lead, nickel, lithium, and molybdenum have medium enrichment). Being contaminated with hydrocarbon material and upstream processes of the oil industry, used elements in chemical and biological weapons and also dryness of lagoons and saline lands were effective in an unusual amount of these components.

In the recent years, the southern basin of Caspian Sea has been faced with several extreme climatic events including droughts, heavy rain falls, snowfalls and floods and heat waves. The study area covers all stations with at least 30 years’ observation data which are located in the southern basin of Caspian Sea. The Downscaling on to precipitation and temperature parameters has been performed for the period of 2010-2099 by using both of statistical and dynamical methods under SRES A2 and B2. SDSM as a statistical tool has been used for the whole period (1961-2099). The results have been evaluated in monthly and yearly time-scales. In yearly timescale, we found that mean of precipitation will decrease significantly, especially over central and western parts of the study area. Also, minimum and maximum of decreasing in annual precipitation belong to the Gorgan and Babolsar stations between 24. 7 – 59. 6 percent, respectively. The total number of daily maximum precipitation with 10, 20 and 30 mm/day and with 95 and 99 percentiles will be increased over all stations and under A2 and B2 scenarios during the next decades of 2011-2039, 2040-69 and 2070-2099. Mean increasing in annual temperature of the study area is projected to be 1-1. 8, 1. 9-3. 3 as well as 2. 4-5. 1 C0in the period of 2011-2039, 2040-69 and 2070-2099, respectively. The total number of frost days has been decreased significantly as well. The final results of SDSM as statistical method and PRECIS as a dynamical method are matched to each other.

Weather and climate events occasionally depending on their size and occurrence can be classified as natural disaster and unexpected that they create serious problems in the process of human life. Including in around of Iran, we are witnessing such events that one of the most dangerous is heavy snowfall days, particularly in the southern part of the Caspian Sea and especially Gillan Plain. One of the heaviest snowfall events at the study region is related to 2014 (1392). This observational study attempts to determine factors responsible for the occurrence of heavy snowfall as well atmospheric circulation at the time of occurrence, also created biological problems. The heavy snowfall that continued for several days had caused a serious disaster in the area. According to the results and identification of the snowy days, synoptic maps at the time of occurrence were prepared and analyzed. The NCEP/NCAR data reanalysis was used to clarify the structure of atmospheric circulation of heavy snowfall over the studied area. Sea level pressure, Geopotential Height, Zonal (U) and Meridional (V) wind, Specific humidity, Omega and Outgoing Longwave Radiation were used to determine the atmospheric circulation of snowfall. The results show that the precipitation has continued in Gilan plane for 5 days (30JAN, 31JAN, 1FEB, 2FEB and 3FEB). Anzali station had the highest and Manjil experienced the lowest amount. The most important factor of atmospheric circulation was strong high pressure formed in the Northern parts of Europe. This high pressure was transformed over the Caspian Sea by the Southward streams. The extreme differences in temperature between the air mass and the sea water had caused the intense convection and strong arising from the area that has led to heavy snowfall. Some of the major problems depending on this natural disaster were serious issues of resident livelihood and blocked roads of towns and villages. So to improve the management of any natural disaster, predicted this natural event early, setting up a comprehensive program to create a proper operational structure with executive ability can fix problems quickly and cause the least damage and casualties.

Precipitation is one of the most important climatic phenomena. Understanding the spatial and time distribution of precipitation has a significant role in the planning and management of water resources and flood risks. In this study, daily precipitation data from synoptic, climatology and rain-gauge stations of Sistan and Baluchestan during 25 year period (1990 – 2014) are collected. The numbers of 24 hours precipitation with extreme rainfall of 20 millimeters or more at stations evaluated and by using of Statistical software are investigated. Then zoning map for extreme rainfall of 20 mm by GIS was obtained. Assessing of zoning map showed that the most effect of extreme rainfall has happened in coastal areas and southern province. Time distribution of extreme rainfall showed that 80 percent of extreme rainfalls have happened in cold seasons (autumn and winter). Hence, Synoptic conditions of western systems are assessed. Applying synoptic analysis of different maps such as humidity levels of 500 and 700 H. P., sea level pressure, 500 H. P. pressure and convective available potential energy maps, showed that enriching of precipitation systems by the Persian Gulf and Oman Sea in cold seasons are caused extreme rainfall of 20 mm in Sistan and Baluchestan Province.

Tehran has in the South of Alborz Mountains and located, in one of the higher parts of the mountain. That's why during the cold period frequently affected by severe frosts and poorly placed. Tehran, with a population of over 8 million people and more than 3 million vehicles at the time of freezing disorders are plenty of daily transportation. for study the characteristics of ice in Tehran, by examining all the weather stations in Tehran during a period of (2011-1985), First, was investigated the same amount of thermal stations Tehran. Then light frost days Was extracted (minimum temperature between 0 to-1/1, Ice average between-1/1 to-2/2, severe frosts less than-2/2). Then map the number of days of frost, frost season, and ice, mild, moderate, severe and associated with the likelihood of them is drawn. The results indicate that the probability of 50%, the probability first frost in northern Tehran stations Aminabad is December, and in Mehrabad, Doshantape and Geophysics stations, are January and Cheetgar station is February. It can be seen on the first severe frosts in January probability level of 50 percent in all stations, but the date of the last frost in the station can be seen in the months of February and March. In terms of the total number of frost days, over 50 days area the ice to the northern end in Tehran is limited, which includes the northern regions is 1, 2, 5, 14 and 22. The total number of frost days zone like sea waves as well corresponds with topographic contour line, to the south of Tehran is reduced. Only the South East of Tehran because of its proximity to the heights of this order is disturbed. Zoning in Tehran is generally along the north-south. While examining patterns of spatial and temporal variability of temperature parameters show that Ice Area, West-East is spread pattern. So, the snow and ice the advance and retreat. Along the contours.

Flood is known as one of the most devastating natural hazards which cause great damages to human societies, municipal, industrial and agricultural centers. Flood estimation in confluence points of rivers– for being the location for many infrastructures – due to economic and environmental matters receives a great importance. It is possible to estimate the flooding likelihood by examining the number of floods with specified return period. In this study, according to the statistical data of peak flows between 1358 to 1379 Hijri-Shamsi in the basin of the Qarah-Soo in Kermanshah Province, annual peak flows were estimated using copula in four models of 1) regression 2) summation 3) weight factor and 4) the nearest stations. For this, first, homogeneity and data quality were investigated. The probability distributions were fit to the data series and with regard to marginal distribution functions of upstream stations, joint distribution function at the confluence was obtained by the Archimedean copula functions. Based on the best copula function for upstream stations, Gumbel copula function was selected. Results showed that copula function in the form of regression was superior to the other models with a coefficient of determination equals to 0. 711, RMSE equals to 79. 387, Kendall's tau correlation coefficient equals to 0. 872 and Spearman Rho coefficient equals to 0. 677. Eventually, discharge amounts for different return periods were calculated according to the selected model.

Correct understanding Dimensions and principles Crisis Management From earthquake in urban areas can as the first step in the process Crisis Management and as one of the most basic instructions direction Implementation of Crisis Management earthquake is considered. In order normative planning to reduce the vulnerability of urban buildings and to present a clear picture of possible occurrence of earthquake and its consequences, assessment of urban vulnerable zones is essential. The aim and methodology of this research are applied and descriptiveanalytical, respectively. In order to vulnerability evaluation of worn out tissues of Mohtasham district of Kashan city, from the perspective of disaster management, the AHP model and for weighting of indices, Expert choice software, were used. To assess of the vulnerability, 9 indices were used. The extent of damages to buildings of this district of city has been divided in five groups: very low vulnerable, low, medium, high and complete destruction. The results showed that, in terms of vulnerability, 10 percent of district in very low, 19 percent in low, 15 percent in medium, 47 percent in high and 9 percent are located in very high vulnerability. Spatial distribution of vulnerability in the center of district is more than the other places due to non-use of resistant materials, undesirable quality and high antiquity of buildings. According to relevant results. Due to physical problems of Mohtasham, earthquake crisis management approach is as an effective solution in order to preserve the tissue and reduce damages to the tissue because of earthquake.

Global warming or climate change, one of the most serious environmental challenges and the long term effects it, can have social, economical and environmental consequences. Also The agricultural sector is one of the sectors most vulnerable to climate change. Since the farmers are the critical decision makers in terms of how to manage agricultural land to adapt to changing climate conditions, their beliefs and risk perception toward climate change are important factors for the adaptation of farmers. therefore The aim of this study was to determine factors affecting farmers’ beliefs and risk perception. The sample is based on Cluster random sampling selected among farmers in Khouzestan province (n=400). The results of regression showed that, among the research variables, the variable trust in media is strongest predictor of belief in the occurrence of climate change (β = 0/25) and belief in the causes of climate change (β =0/23). Also, the risk salience is the strongest predictor of belief in the effects of climate change (β = 0/35) and belief in the effects of climate change, is the most powerful predictor of perceived risk (β = 0/35). On the results of research, Recommendations for development of risk perception and beliefs toward climate change and drought are offered.

There are seven methods for estimating NBS, which include: channel pattern and bar assessment, ratio of radius of curvature to bank-full width (Rc/Wbkf), ratio of pool slope to average water surface slope (Sp / S), ratio of pool slope to rifle slope (Sp/Srif), ratio of near-bank maximum depth to bank-full mean depth (dnb/dbkf), ratio of nearbank shear stress to bank-full shear stress (τ nb/τ bkf) and use of velocity profile/isovel/velocity gradients. In this article, three methods were selected for estimating Near Bank Stress (NBS); Rc/Wbkf, dnb/dbkf, τ nb / τ bkf and then according to these methods, the erosion of the Galali river banks were determined at different levels from very low to extreme. Results showed that in the method radius of curvature to bank-full width (Rc/Wbkf), the bank erosion was moderate to very low and in the method near-bank maximum depth to bank-full mean depth (dnb/dbkf) in most cross-sections, the bank erosion was low and in method near-bank shear stress to bank-full shear stress (tnb/tbkf) the bank erosion was very high. Also, curvature coefficient shows that the river is sinuosity in cross-sections 1, 2 and 3 and is a meandering river in cross-sections 4 and 5. Comparing the results and field observation shows that the method near-bank maximum depth to bank-full mean depth is acceptable. Finally, in the Galali river, results of near-bank maximum depth to bank-full mean depth (dnb/dbkf) for assessment of the bank erosion (NBS) is better than method radius of curvature to the bank-full width (Rc/Wbkf) and near-bank shear stress to bank-full shear stress (tnb/tbkf). The Galali river has low to moderate bank erosion potential. Also, the river is sinuosity in upstream and is meandering in downstream and according to field observation, bank erosion potential in downstream of the Galali river is more that upstream.

An earthquake, generally considered being the most destructive and frightening of all forces of nature is a sudden rapid shaking of the earth caused by the breaking and shifting of rock beneath the earth’ s surface. More casualties and financial losses due to secondary effects of the earthquake and after they occur. Iran is seismically active country and frequent and destructive earthquakes reveal the fact in different parts of the country. For example, two severe earthquakes happened on Sunday 21 Mordad 1391 in areas of East Azerbaijan province. Earthquake magnitude were 6/4 and 6/3 on the Richter scale near the Varzeghan and Ahar. The epicenter of both quakes was at a depth of 10 kilometers underground. The earthquake strongly shook towns of Ahar, Haris, and Varzeghan. It created a lot of casualties and financial losses. This study tries to draw a map of seismicity in the Sarand Chai and around the area, using seismic data to Tehran University Geophysics Agency, satellite imagery review the evidence and Frequent field observations whit use Arc/GIS. Finally, It is zoning the risk of landslides in the area in the event of an earthquake with the strength of 6. 4 on the Richter scale. The results of this study show, the hazard of the earthquake in Ahar-Varzeghan include shaking, the type of landslides (slides, rock falls, debris flows… ), ground rupture, liquefaction, groundwater level fluctuations and etc., based on field observations of the region. The zonation map show, that in the event of an earthquake with a strength of 6. 4 on the Richter scale, will be 7% of the area in the very high hazard zone, 35 % in the high hazard zone and 7 % of the area in the low hazard zone, in terms of landslides occurrence.