Sustainable Earth Review
Volume:1 Issue: 2, May 2021

The coronavirus disease or the so-called Covid-19 is a highly transmittable and pathogenic viral infection which emerged in Wuhan, China and spread rapidly around the world. The virus has resulted in about 4.2 million infections and 280,000 deaths (as of 10 May, 2020). Covid-19 is affecting not only health, economy, culture and life style but also it is going to affect the ecosystems and environment of the world. The ideas about role of this crisis in ecosystem and environment are quite different. Optimists believe that this crisis is the best opportunity to reduce pressure on natural resources and provides time for self-reconstruction of the ecosystems and environment. The pessimist, on the other hand, state that the positive effects of Covid-19 on the environment is not much and would diminish soon, and the earth is hurtling towards a catastrophe worse than the dinosaur extinction. The most positive impacts of this crisis are reduced pressure on natural resources, decreasing in air pollution and climate change, deeper understanding of the ecosystems and environment saving. The significant negative impacts of this crisis are human infection and death, billions USD in economic losses, increasing in household consumption, medicine, faces masks and medical gloves and challenge for burial of household and medical waste, reduction in environmental diplomacy, reduction in accuracy of weather forecasts and treat for wildlife infection. Iran is the home to the second most infected and recovered cases (up to 75%) after China. Several impacts have been reported on the human and natural environment of Iran. The virus has resulted in about 108,000 infections and 6,700 deaths (as of 10 May, 2020). In response to coronavirus, the government cancelled public events such as Friday prayers, festival celebrations, and sporting events, as well as closed schools, universities, shopping centers, bazaars, and even holy shrines. Consequently, the spread of infection is relatively controlled from over 200 to about 40 deaths per day. The impacts on the ecosystems and environment of Iran are similar to that reported in other parts of the world.

Rivers in Iran are heavily influenced by human activities, so that they have undergone many changes. In the meantime, gravel mining is one of these activities that has several environmental impacts on the various aspects of river environments. The study area is located in the plain of Mazandaran Province in Iran. The concerned rivers originate from the northern slopes of the Alborz Mount and flow into the Caspian Sea. Most of the mountainous areas are covered with thicket forests, and in the plain section, agricultural lands and human habitats are the dominant land uses in the region. The geomorphic effects of sediment mining from river have been investigated in four aspects including river longitudinal profile and transverse profile, as well as river pattern and changes in sediment size and amount. In Mazandaran Province, there are more than 60 rivers in which there are more than 80 active gravel mines. These mines are run by governmental, cooperative and private sectors. Currently, the dependence of the construction and development activities of the province on these gravel resources has seriously threatened the river bed with excessive exploitation, so that these exploitations would be of the most destructive activities imposed on the aquatic ecosystems. The results also show that the unauthorized sediments removal from the river bed and the construction of engineering structures to control its geomorphic consequences only delay the performance of river processes and, consequently, delay the morphological adjustments.

Avalanche is one of the natural disasters that annually inflicts heavy casualties on human societies, especially the world's transportation systems, especially in mountainous areas. The use of remote sensing and radar interference knowledge is one of the expanding and efficient methods in identifying changes in the earth's surface, especially avalanches. In this study, radar imaging interference and offset tracking techniques were used to identify the avalanche incident on Chalus Road. The basis of this method is to determine the extent of changes in the characteristics of the Earth's surface, which is determined by changes in radar redistribution. This process is done by comparing the Sentinel-1 radar images before and after the event. After ensuring the results of radar interference by matching it in the Google Earth environment, using the histogram diagram, the frequency changes of radar distribution pixels, the average velocity of avalanche mass displacement in the domain were determined. Based on this, the maximum velocity of Avalanche mass was 45 cm and the maximum displaced volume of Avalanche mass was determined on a slope with a velocity of 5 cm per day, which indicates that the snow mass forming Avalanche has been moved in several stages and along with geomorphological characteristics. The area, the snowfall, and the increase in its volume on the slope have gradually overcome the frictional force between the slope surface and the lower part of the snow mass, causing the avalanche mass to move down the road.

Fluvial sediment dating surveys are one of the quaternary researches which can help to explicit many environmental issues. In the present study, samples taken to direct age determination belong to a depositional profile located in one of the tributaries of Saqqez River. This profile is located at southwest of Saqqez city and at the outlet of Saqqez basin. The OSL method was used to determine the age of three samples including sandy lens, floodplain and conglomerate sediments. 14C and U/Th methods was applied to dating of the charcoal in conglomerate sediments and pedogenic/ cement carbonates respectively.  The age of the unit is constrained by OSL dating of a sandy lens, at the base of the profile, at 68.35±9.50 ka and the overlying floodplain deposits at 26.76±6.96 ka (i.e. Late Pleistocene). Floodplain consolidated sediment (conglomerate) has been OSL dated at 5.79±1.88 ka which belongs to Mid-Holocene period. Concerning the fluvial sediments ages by the U/Th method, it should be noted that since the ratio of thorium to uranium was much higher than its standard value in both pedogenic and cement carbonate samples, it is not possible to determine the age of carbonate samples using the uranium series method. The calendar age reported by 14C is around 1995, looks enigmatic considering the context from which the sample has been collected and the time required for crystallization of the enclosing carbonate cements. Therefore, it seems that among the different methods of fluvial sediment absolute dating methods, luminescence is more suitable for quaternary fluvial sediments dating in Saqqez River basin.

Landslide is among the most damaging ones, which has been accelerating in recent decades as human manipulation of natural systems has occurred. Mountain cliff Khan is located on the path of Saghez-Baneh and is considered as a highway to the west of the country and given the fact that it is located in mountainous areas and the probability of occurrence mass movements in the region are high, for this reason in this research, we have attempted to identify areas susceptible to mass movements in the studied area. Therefore, the method of descriptive-analytical work is considered as a type of component of applied research. The methodology is that after the preparation and insertion of information, the information layers are standardized by fuzzy logic method. And then through the AHP model, the information layers are weighed and then combined with the two methods of OWA and WLC. As a result, areas susceptible to mass motion are identified using these two methods. The results of the evaluations indicate that the areas around mountain Khan Tunnel due to the high slope, high altitude, proximity to the drainage network, adjacent proximity to the fault lines, there is a high potential for mass movement. The results of the comparison of the two methods indicate that in general, the areas around the mountain Khan tunnel because of slope and height and human interference have the highest potential and the risk is reduced to the surrounding area.

In this study, 7 images of OLI and EMT sensors of Landsat 7 and 8 satellites and multi-time images of TM sensor satellite 5 have been used. These images cover the period from 1987 to 2018 (31-year period); after applying processing to satellite imagery, land use layers were prepared by supervised classification method. Then, using the thermal equations and the center algorithm, the similarity of the surface temperature of the earth for the periods of 1978, 2000, and 2018 was calculated for the study area in four stages. Results indicate that barren lands in 1987 had the largest area with 437 km and the use of irrigated land had the least area with. Studies have also shown that from 2000 to 2018, due to the increase in urban population and migration to this city and the expansion of housing construction, residential use has gradually increased to an area of 446  and the amount of land use in barren lands has decreased to 431 square kilometers. Survey of temperature with temperature changes showed that in 1987, the temperature in barren land uses reached a maximum temperature of 48  outside the suburbs, and from 2000 to 2018, land use in the northwest and west of the metropolis reached 56 to 70. Examination of the results shows that during the study year, due to population growth and the growing trend of residential use in the metropolis due to the replacement of buildings, the Cement and Asphalt Organization will absorb these levels more than they reflect the sun and has increased the temperature in urban areas. This application is considered as the creator of the thermal island for the metropolis.