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Volume 20, Issue 3 (10-2020)
Abstract
The history of the human efforts for safety against earthquakes shows the catastrophic and harmful events, even nowadays. The majority of decisions in seismic safety policy are based on randomness assumption for earthquake time series. The accuracy of this assumption assessment, can accurate the strategies and resulted in more secure decisions. Also in structural control context, seismic time series prediction in the feedback systems, can reduces the time of control system reaction and in subsequent decreases structural damages. Recent studies have shown that dynamical structure of these complex time series can be better understand using nonlinear dynamics theory. In the present paper, we evaluate randomness and nonlinear characteristics of 9 earthquakes time series from metropolitan Tehran earthquake database using chaos theory conceptions. These earthquakes are Arjomand, Bumahen, Damavand, Eshtehard, Firuzkooh, Taleqan 1, Taleqan 2, Taleqan 3 and Tehran earthquake. To this end, we reconstruct phase space for delay time calculation using average mutual information function. Embedding dimension is calculated based on false nearest neighbors. Correlation dimension is used for earthquake chaotic behavior assessment and local prediction algorithm and artificial neural network are employed for earthquake prediction. Results illustrate nonrandom nature of evaluated earthquakes. These earthquakes have high dimension chaotic behavior. Earthquake prediction is good and acceptable accuracy using chaos theory and artificial neural network. The existence of the specific attractors in a part of 2D reconstructed phase space for the earthquakes show the presence of a nonlinear processes. This is an evidence for no stochastic behavior of the earthquakes. Also, reduction in the false neighbors with embedding dimension increases, shows no stochastic time series. Lyapanov exponent positive gradient displays a nondeterministic process, although it cannot warranty the chaotic behavior. Correlation exponents have high values for Taleqan1 and Tehran earthquakes. So these earthquakes saturate in large quantities. Bumahen and Damavand earthquakes correlation exponents have increasing trend and do not saturate. These observations prove the chaotic behavior of high dimension or random process with inconsiderable chaos. So these earthquakes cannot be predicted properly. Performing the local prediction based on the selected embedding dimensions and the neighbor’s number, showed that the predicted time series are relatively good for the earthquakes of Arjomand, Eshtehard, Firuzkooh, Taleqan 2 and Taleqan 3. Proper anticipated of trends, upward and downward branches as well as amplitudes illustrate the chaotic nature of the earthquakes. The correlation coefficient for Arjomand, Eshtehard, Firuzkooh, Taleqan 2 and Taleqan 3 are 0.9541, 0.4494, 0.5124, 0.6600 and 0.3697 respectively. In the case of Talegan1 and Tehran earthquakes, time series amplitudes and peaks do not predicted appropriately, but the prediction is acceptable. Correlation coefficient of Taleqan1 and Tehran are 0.2452 and 0.1760 respectively. Bumahen and Damavand earthquakes do not trace properly. It should be noted that for each earthquake, 20% of the endpoints of accelerations are used to evaluate the prediction process. According to the results of the analysis and earthquakes prediction in Tehran region, using phase reconstruction and artificial neural networks, we can say that the dynamics governing the earthquakes in this region are not random, but, chaos with high dimension. Earthquake prediction is good and acceptable accuracy using chaos theory and artificial neural network.
Volume 24, Issue 1 (Spring 2020)
Abstract
Introduction
In recent years, the world has been witnessing climate change which is mostly due to socio-economic activities of man and in turn producing greenhouse gas emissions. These actions have been led to global warming, melting of glaciers and extreme variability of weather indicators such as rainfall and temperature. These changes in our country have also shown itself in phenomena like snowfall shortage, devastating floods and storms, terrible and out-of-season storms, and unprecedented summer heat. These Climate fluctuations have had significant effects on different sub-sectors of the economy, especially agriculture, and the phenomenon of climate change in agriculture has shown itself at the first step in different forms of drought. Increasing farmers' resilience and adaptability to climate change are the major strategies that many countries have taken into account to face and confront the negative consequences of drought. One of the provinces that are facing drought phenomenon in Isfahan Province. For example, conflicts among farmers on water shortages and water transfers from this province to the neighboring provinces and crisis in Zayandeh Rood River are just some proof showing the severity of the situation.
Methodology
Based on the present study, the SWOT Matrix was used to identify the strengths, weaknesses, opportunities, and threats of small-scale farmers' adaptation to drought conditions in Isfahan province. Therefore, appropriate strategies were developed and proposed to achieve this objective. The statistical population of this research consisted of 110 experts working in the field of drought management in Isfahan province out of which, 88 people were selected on the basis of the Krejcie & Morgan table. The main instrument of this study was a questionnaire whose content validity was confirmed by the opinions of an expert panel in the Department of Agricultural Development and Management at the University of Tehran and its reliability was confirmed by Cronbach's alpha coefficients. In order to find appropriate strategies, the TOWS matrix was developed and used in this study. This method integrates scientific and theoretical opinions with application remarks. This method is innovative and provides lights to workable strategies based on a reasonable and appropriate framework.
Result and Discussion
Based on the results of study, the most important opportunities for the adaptation of small-scale farmers to drought condition were the "implementing rainwater harvesting programs", "improving urban potable and green-space water management " and "national support for all strategies related to adaptability to climate change in formulating appropriate policies and regulations" It is while the most important threats found to be "weak governmental administrative works for recognition and management of climate change consequences", "insufficient supportive credit for drought management" and "insufficient attention by government to extension education programs related to drought management", In terms of the internal environment, the most important strength was found to be "Increasing farmers assets and their productive power, “cooperation of farmers to manage drought" and "Strengthening farmers Organizations ". Besides, the most important weaknesses were identified as “the low willingness of farmers to apply technologies for reducing greenhouse gases emission", "high cost of irrigation equipment to reduce water consumption" and "decreasing farms resilience towards climate change".
Conclusion
Drought covers about 80% of Isfahan province and 22.5% of the province has been faced with severe drought. A survey of drought conditions over the past years indicates that most parts of Isfahan province are affected by drought. The drought has had many detrimental effects on different parts of the province, including agriculture, industry, services, the environment, public and cultural green spaces. Desertification, air pollution, and dust generation, relative humidity reduction, soil moisture depletion, rangeland wildfire, salinization and depletion of groundwater resources, damage to historic structures are some examples of the negative consequences drought in Isfahan province. In addition, the direct effects of water scarcity on agriculture and other socio-economic sectors are evident. Outbreaks of pests and plant and animal diseases, increased agricultural migration to cities, loss of productive livestock, reduced aquaculture, and the crisis of access to potable water and reduction of farm productivity in rural areas have been observed and reported as some of the effects of drought. Accordingly, the present study was conducted to find appropriate coping strategies. However, in analyzing the strategic space, the results showed that the most efficient and adaptive strategies in the Jihad Agriculture Organization of Isfahan Province are placed in the ST area. Moreover, using a TOWS matrix, some other agricultural adaptive strategies were formulated to be used in the drought conditions of the province. SO strategies recommend operations such as Diversification of Resistant Crops, Improving interaction between actors in the agricultural production chain and Proper management of floods through water harvesting projects. Under ST strategies operations such as paying attention to support programs and subsidizing drought management among farmers, Support diversification of livelihood investments for agriculture in times of drought crisis and strict monitoring of groundwater harvesting through the strengthening of aquifers are suggested. WO strategies focus on operations like Using modern irrigation equipment in agriculture through government support for water management projects, Improving specialized drought information for farmers by improving the efficiency of technical-engineering companies in providing services to farmers and Reduce farmers' migration by supporting livelihood adaptation strategies in government programs and projects. WT strategies also place its attention on operations such as Convergence of public and private sectors in implementing drought management programs and providing specialized information to farmers, Change the cropping pattern with the aim of developing drought-resistant varieties, Defining a clear role for farmers in drought management in agricultural development programs.
In recent years, the world has been witnessing climate change which is mostly due to socio-economic activities of man and in turn producing greenhouse gas emissions. These actions have been led to global warming, melting of glaciers and extreme variability of weather indicators such as rainfall and temperature. These changes in our country have also shown itself in phenomena like snowfall shortage, devastating floods and storms, terrible and out-of-season storms, and unprecedented summer heat. These Climate fluctuations have had significant effects on different sub-sectors of the economy, especially agriculture, and the phenomenon of climate change in agriculture has shown itself at the first step in different forms of drought. Increasing farmers' resilience and adaptability to climate change are the major strategies that many countries have taken into account to face and confront the negative consequences of drought. One of the provinces that are facing drought phenomenon in Isfahan Province. For example, conflicts among farmers on water shortages and water transfers from this province to the neighboring provinces and crisis in Zayandeh Rood River are just some proof showing the severity of the situation.
Methodology
Based on the present study, the SWOT Matrix was used to identify the strengths, weaknesses, opportunities, and threats of small-scale farmers' adaptation to drought conditions in Isfahan province. Therefore, appropriate strategies were developed and proposed to achieve this objective. The statistical population of this research consisted of 110 experts working in the field of drought management in Isfahan province out of which, 88 people were selected on the basis of the Krejcie & Morgan table. The main instrument of this study was a questionnaire whose content validity was confirmed by the opinions of an expert panel in the Department of Agricultural Development and Management at the University of Tehran and its reliability was confirmed by Cronbach's alpha coefficients. In order to find appropriate strategies, the TOWS matrix was developed and used in this study. This method integrates scientific and theoretical opinions with application remarks. This method is innovative and provides lights to workable strategies based on a reasonable and appropriate framework.
Result and Discussion
Based on the results of study, the most important opportunities for the adaptation of small-scale farmers to drought condition were the "implementing rainwater harvesting programs", "improving urban potable and green-space water management " and "national support for all strategies related to adaptability to climate change in formulating appropriate policies and regulations" It is while the most important threats found to be "weak governmental administrative works for recognition and management of climate change consequences", "insufficient supportive credit for drought management" and "insufficient attention by government to extension education programs related to drought management", In terms of the internal environment, the most important strength was found to be "Increasing farmers assets and their productive power, “cooperation of farmers to manage drought" and "Strengthening farmers Organizations ". Besides, the most important weaknesses were identified as “the low willingness of farmers to apply technologies for reducing greenhouse gases emission", "high cost of irrigation equipment to reduce water consumption" and "decreasing farms resilience towards climate change".
Conclusion
Drought covers about 80% of Isfahan province and 22.5% of the province has been faced with severe drought. A survey of drought conditions over the past years indicates that most parts of Isfahan province are affected by drought. The drought has had many detrimental effects on different parts of the province, including agriculture, industry, services, the environment, public and cultural green spaces. Desertification, air pollution, and dust generation, relative humidity reduction, soil moisture depletion, rangeland wildfire, salinization and depletion of groundwater resources, damage to historic structures are some examples of the negative consequences drought in Isfahan province. In addition, the direct effects of water scarcity on agriculture and other socio-economic sectors are evident. Outbreaks of pests and plant and animal diseases, increased agricultural migration to cities, loss of productive livestock, reduced aquaculture, and the crisis of access to potable water and reduction of farm productivity in rural areas have been observed and reported as some of the effects of drought. Accordingly, the present study was conducted to find appropriate coping strategies. However, in analyzing the strategic space, the results showed that the most efficient and adaptive strategies in the Jihad Agriculture Organization of Isfahan Province are placed in the ST area. Moreover, using a TOWS matrix, some other agricultural adaptive strategies were formulated to be used in the drought conditions of the province. SO strategies recommend operations such as Diversification of Resistant Crops, Improving interaction between actors in the agricultural production chain and Proper management of floods through water harvesting projects. Under ST strategies operations such as paying attention to support programs and subsidizing drought management among farmers, Support diversification of livelihood investments for agriculture in times of drought crisis and strict monitoring of groundwater harvesting through the strengthening of aquifers are suggested. WO strategies focus on operations like Using modern irrigation equipment in agriculture through government support for water management projects, Improving specialized drought information for farmers by improving the efficiency of technical-engineering companies in providing services to farmers and Reduce farmers' migration by supporting livelihood adaptation strategies in government programs and projects. WT strategies also place its attention on operations such as Convergence of public and private sectors in implementing drought management programs and providing specialized information to farmers, Change the cropping pattern with the aim of developing drought-resistant varieties, Defining a clear role for farmers in drought management in agricultural development programs.
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