scholarly journals Aspects of risk assessment in power-law distributed natural hazards

2004 ◽  
Vol 4 (2) ◽  
pp. 309-313 ◽  
Author(s):  
S. Hergarten

Abstract. Risk assessment is mainly based on certain scenarios involving an event of a certain size which is thought to be characteristic for the considered type of hazard. However, many natural hazards extend over a wide range of event sizes, and some of them are even free of characteristic scales. An expression for the risk taking into account various event sizes is derived, and its implications on risk assessment for earthquakes, forest fires, landslides, and rockfalls are discussed. Under simple assumptions on the damage as a function of the event size, it turns out that the total risk is governed by either the small number of large events or the majority of small events. The distinction between these two classes depends on both the power-law exponent of the event size distribution and the damage function. For earthquakes, forest fires, and rockfalls, the total risk is mainly constituted by the largest events, while results are non-unique for landslides.

2009 ◽  
Vol 9 (1) ◽  
pp. 211-216 ◽  
Author(s):  
F. Vallianatos

Abstract. We analytically estimate the risk function of natural hazards (earthquakes, rockfalls, forestfires, landslides) by means of a non-extensive approach which is based on implementing the Tsallis entropy for the estimation of the probability density function (PDF) and introducing a phenomenological exponential expression for the damage function. The result leads to a power law expression as a special case and the b-value is given as a function of the non-extensive parameter q. A discussion of risk function dependence on the parameters of hazard PDF and damage function for various hazards is given.


2010 ◽  
Vol 1254 ◽  
Author(s):  
J. Yates Coulter ◽  
David W. Reagor ◽  
Jeffrey O. Willis ◽  
Terry G. Holesinger

AbstractIn-field critical current Ic variations, detected using a short sample, angular Ic(77K, H=5.2kOe, Angle) measurement on the ends of a 20 m coated conductor tape fabricated by the MOD / RABiTS process, are shown to be variations in the Ic(H) anisotropy that exist on subcentimeter length scales. A Ic(75 K, H, Angle) study was performed on segments cut from the tape where the power law exponent of the field dependence, α, Ic ∼H−α was calculated for Ic(H, Angle) data. Two extrema behaviors, anisotropic and isotropic, were identified. The isotropic material is shown to outperform the anisotropic material for a wide range of fields and angles at T=26 K.


Author(s):  
Максим Дмитриевич Корабель ◽  
Илья Владимирович Синёв ◽  
Дмитрий Алексеевич Шикунов ◽  
Никита Александрович Клычков ◽  
Дмитрий Александрович Тимошенко ◽  
...  

В широком диапазоне концентраций газов различной химической природы (аммиака, ацетона, пропанола и этанола) исследовалась концентрационная зависимость газочувствительности сенсора газа на основе наноструктурированной пленки диоксида олова при различных режимах его работы. Экспериментально показано, что концентрационная зависимость газочувствительности носит степенной характер, показатель степени n различен для разных газовых проб, причем величина показателя степенного закона n зависит от режима работы сенсора и химической природы анализируемой пробы. Изученное явление позволяет распознавать газовые пробы, содержащие пары веществ различной химической природы. Вероятность классификации газовых проб аммиака, ацетона, пропанола и этанола методом ближайших соседей составила более 95 %. The concentration dependence of the gas sensitivity of a gas sensor based on a nanostructured tin dioxide film was studied under various operating conditions in a wide range of concentrations of gases of various nature (ammonia, acetone, propanol, and ethanol). It has been experimentally shown that the concentration dependence of the gas sensitivity is power-law, the exponent n is different for different gas samples, and the value of the power-law exponent n depends on the operating mode of the sensor and the chemical nature of the sample being analyzed. The studied phenomenon makes it possible to recognize gas samples containing vapors of different chemical substances. The probability of classification of gas samples of ammonia, acetone, propanol and ethanol by the method of nearest neighbors was more than 95 %.


Author(s):  
Sergei Soldatenko ◽  
Sergei Soldatenko ◽  
Genrikh Alekseev ◽  
Genrikh Alekseev ◽  
Alexander Danilov ◽  
...  

Every aspect of human operations faces a wide range of risks, some of which can cause serious consequences. By the start of 21st century, mankind has recognized a new class of risks posed by climate change. It is obvious, that the global climate is changing, and will continue to change, in ways that affect the planning and day to day operations of businesses, government agencies and other organizations and institutions. The manifestations of climate change include but not limited to rising sea levels, increasing temperature, flooding, melting polar sea ice, adverse weather events (e.g. heatwaves, drought, and storms) and a rise in related problems (e.g. health and environmental). Assessing and managing climate risks represent one of the most challenging issues of today and for the future. The purpose of the risk modeling system discussed in this paper is to provide a framework and methodology to quantify risks caused by climate change, to facilitate estimates of the impact of climate change on various spheres of human activities and to compare eventual adaptation and risk mitigation strategies. The system integrates both physical climate system and economic models together with knowledge-based subsystem, which can help support proactive risk management. System structure and its main components are considered. Special attention is paid to climate risk assessment, management and hedging in the Arctic coastal areas.


2021 ◽  
Vol 13 (10) ◽  
pp. 5369
Author(s):  
Rajesh Khatakho ◽  
Dipendra Gautam ◽  
Komal Raj Aryal ◽  
Vishnu Prasad Pandey ◽  
Rajesh Rupakhety ◽  
...  

Natural hazards are complex phenomena that can occur independently, simultaneously, or in a series as cascading events. For any particular region, numerous single hazard maps may not necessarily provide all information regarding impending hazards to the stakeholders for preparedness and planning. A multi-hazard map furnishes composite illustration of the natural hazards of varying magnitude, frequency, and spatial distribution. Thus, multi-hazard risk assessment is performed to depict the holistic natural hazards scenario of any particular region. To the best of the authors’ knowledge, multi-hazard risk assessments are rarely conducted in Nepal although multiple natural hazards strike the country almost every year. In this study, floods, landslides, earthquakes, and urban fire hazards are used to assess multi-hazard risk in Kathmandu Valley, Nepal, using the Analytical Hierarchy Process (AHP), which is then integrated with the Geographical Information System (GIS). First, flood, landslide, earthquake, and urban fire hazard assessments are performed individually and then superimposed to obtain multi-hazard risk. Multi-hazard risk assessment of Kathmandu Valley is performed by pair-wise comparison of the four natural hazards. The sum of observations concludes that densely populated areas, old settlements, and the central valley have high to very high level of multi-hazard risk.


Author(s):  
David Callaway ◽  
Jeff Runge ◽  
Lucia Mullen ◽  
Lisa Rentz ◽  
Kevin Staley ◽  
...  

Abstract The United States Centers for Disease Control and Prevention and the World Health Organization broadly categorize mass gathering events as high risk for amplification of coronavirus disease 2019 (COVID-19) spread in a community due to the nature of respiratory diseases and the transmission dynamics. However, various measures and modifications can be put in place to limit or reduce the risk of further spread of COVID-19 for the mass gathering. During this pandemic, the Johns Hopkins University Center for Health Security produced a risk assessment and mitigation tool for decision-makers to assess SARS-CoV-2 transmission risks that may arise as organizations and businesses hold mass gatherings or increase business operations: The JHU Operational Toolkit for Businesses Considering Reopening or Expanding Operations in COVID-19 (Toolkit). This article describes the deployment of a data-informed, risk-reduction strategy that protects local communities, preserves local health-care capacity, and supports democratic processes through the safe execution of the Republican National Convention in Charlotte, North Carolina. The successful use of the Toolkit and the lessons learned from this experience are applicable in a wide range of public health settings, including school reopening, expansion of public services, and even resumption of health-care delivery.


2018 ◽  
Vol 32 (7) ◽  
pp. 866-872 ◽  
Author(s):  
Swagat Patnaik ◽  
Basudev Biswal ◽  
Dasika Nagesh Kumar ◽  
Bellie Sivakumar

2005 ◽  
Vol 73 (3) ◽  
pp. 461-468 ◽  
Author(s):  
Timothy T. Clark ◽  
Ye Zhou

The Richtmyer-Meshkov mixing layer is initiated by the passing of a shock over an interface between fluid of differing densities. The energy deposited during the shock passage undergoes a relaxation process during which the fluctuational energy in the flow field decays and the spatial gradients of the flow field decrease in time. This late stage of Richtmyer-Meshkov mixing layers is studied from the viewpoint of self-similarity. Analogies with weakly anisotropic turbulence suggest that both the bubble-side and spike-side widths of the mixing layer should evolve as power-laws in time, with the same power-law exponent and virtual time origin for both sides. The analogy also bounds the power-law exponent between 2∕7 and 1∕2. It is then shown that the assumption of identical power-law exponents for bubbles and spikes yields fits that are in good agreement with experiment at modest density ratios.


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