417 research outputs found
Population vulnerability models for asteroid impact risk assessment
No full textAn asteroid impact is a low probability event with potentially devastating consequences. The Asteroid Risk Mitigation Optimization and Research (ARMOR) software tool calculates whether a colliding asteroid experiences an airburst or surface impact and calculates effect severity as well as reach on the global map. To calculate the consequences of an impact in terms of loss of human life, new vulnerability models are derived that connect the severity of seven impact effects (strong winds, overpressure shockwave, thermal radiation, seismic shaking, ejecta deposition, cratering and tsunamis) with lethality to human populations. With the new vulnerability models ARMOR estimates casualties of an impact under consideration of the local population and geography. The presented algorithms and models are employed in two case studies to estimate total casualties as well as the damage contribution of each impact effect. The case studies highlight that aerothermal effects are most harmful except for deep water impacts, where tsunamis are the dominant hazard. Continental shelves serve a protective function against the tsunami hazard caused by impactors on the shelf. Furthermore, the calculation of impact consequences facilitates asteroid risk estimation to better characterize a given threat and the concept of risk as well as its applicability to the asteroid impact scenario are presented
Global impact risk of known asteroids
No full textAsteroids that could collide with the Earth are listed on the publicly available Near Earth Object (NEO) hazard web sites maintained by the National Aeronautics and Space Administration (NASA) and the European Space Agency (ESA). The risk of 69 potentially threatening NEOs that produce 261 dynamically distinct impact instances, or Virtual Impactors (VIs), has been calculated using the Asteroid Risk Mitigation and Optimization Research (ARMOR) tool. ARMOR calculates the impact risk in terms of expected casualties based on three factors: impact probability, exposure and vulnerability. First, the impact probability of each VI is projected onto the surface of the Earth as a spatial probability distribution. The projection considers orbit solution accuracy and the global impact probability. Second, the global population distribution is introduced and represents the exposure to the hazard. Finally, the vulnerability of the population to the physical impact effects produced by a colliding asteroid is calculated. Impact effects are calculated based on asteroid size, impact speed and impact angle and the effects are: crater formation, thermal radiation, seismic shaking, overpressure shock wave, strong winds and the deposition of an ejecta blanket. Population vulnerability is determined based on the severity of the impact effects at a given distance from the impact site. Factoring together impact probability, exposure and vulnerability allows calculation of the risk for each VI as well as the combined risk of the 69 asteroids. To account for the uncertainty in the impact effect models, ARMOR produces three scenarios that represent the least harmful, the expected and the worst case outcomes. Because the risk calculation is dependent on the current impact probability, the risk calculation is subject to significant variability based on the availability of new asteroid observations. The calculated risk expresses the current best estimate of expected casualties that are associated with each asteroid. The method has the potential to form the basis of a new impact hazard threat scale similar to the Torino or Palermo scale. The results are presented in the form of global spatial risk distributions and as quantitative analysis
On the influence of impact effect modelling for global asteroid impact risk distribution
No full textThe collision of an asteroid with Earth can potentially have significant consequences for the human population. The European and United States space agencies (ESA and NASA) maintain asteroid hazard lists that contain all known asteroids with a non-zero chance of colliding with the Earth in the future. Some software tools exist that are, either, capable of calculating the impact points of those asteroids, or that can estimate the impact effects of a given impact incident. However, no single tool is available that combines both aspects and enables a comprehensive risk analysis. The question is, thus, whether tools that can calculate impact location may be used to obtain a qualitative understanding of the asteroid impact risk distribution. To answer this question, two impact risk distributions that control for impact effect modelling were generated and compared. The Asteroid Risk Mitigation Optimization and Research (ARMOR) tool, in conjunction with the freely available software OrbFit, was used to project the impact probabilities of listed asteroids with a minimum diameter of 30 m onto the surface of the Earth representing a random sample (15% of all objects) of the hazard list. The resulting 261 impact corridors were visualized on a global map. Furthermore, the impact corridors were combined with Earth population data to estimate the “simplified” risk (without impact effects) and “advanced” risk (with impact effects) associated with the direct asteroid impacts that each nation faces from present to 2100 based on this sample. The relationship between risk and population size was examined for the 40 most populous countries and it was apparent that population size is a good proxy for relative risk. The advanced and simplified risk distributions were compared and the alteration of the results based on the introduction of physical impact effects was discussed. Population remained a valid proxy for relative impact risk, but the inclusion of impact effects resulted in significantly different risks, especially when considered at the national level. Therefore, consideration of physical impact effects is essential in estimating the risk to specific nations of the asteroid threat
Asteroid impact effects and their immediate hazards for human populations
No full textA set of 50,000 artificial Earth impacting asteroids was used to obtain, for the first time, information about the dominance of individual impact effects such as wind blast, overpressure shock, thermal radiation, cratering, seismic shaking, ejecta deposition and tsunami for the loss of human life during an impact event for impactor sizes between 15 to 400 m and how the dominance of impact effects changes over size. Information about the dominance of each impact effect can enable disaster managers to plan for the most relevant effects in the event of an asteroid impact. Furthermore, the analysis of average casualty numbers per impactor shows that there is a significant difference in expected loss for airburst and surface impacts and that the average impact over land is an order of magnitude more dangerous than one over water
Recovering Identity
No full textRecovering Identity examines a critical tension in criminalized women’s identity work. Through in-depth qualitative and photo-elicitation interviews, Cesraéa Rumpf shows how formerly incarcerated women engaged recovery and faith-based discourses to craft rehabilitated identities, defined in opposition to past identities as “criminal-addicts.” While these discourses made it possible for women to carve out spaces of personal protection, growth, and joy, they also promoted individualistic understandings of criminalization and the violence and dehumanization that followed. Honoring criminalized women’s stories of personal transformation, Rumpf nevertheless strongly critiques institutions’ promotion of narratives that impose lifelong moral judgment while detracting attention from the structural forces of racism, sexism, and poverty that contribute to women’s vulnerability to violence.
“A deeply moving account of the indignity that women who are criminalized experience as they fight for their freedom. Cesraéa Rumpf’s sharp critique demands that we see the violence of incarceration and deepen our commitment to justice for criminalized women.” — BETH E. RICHIE , coauthor of Abolition. Feminism. Now.
“Recovering Identity makes a major contribution to the study of gender, race, and culture in the era of mass incarceration. Rumpf’s comprehensive analysis of how women counter the negative effects of the criminal legal system is timely, thoroughly researched, and persuasive.” — KEESHA M. MIDDLEMASS, author of Convicted and Condemned: The Politics and Policies of Prisoner Reentry
“Rumpf persuasively demonstrates how 12-step ideology obscures the structural forces driving mass incarceration. A sensitive, rigorous, and compelling contribution.” — MELISSA THOMPSON, coauthor of Motherhood after Incarceration: Community Reintegration for Mothers in the Criminal Legal Syste
Splines in the Space of Shells
No full textCubic splines in Euclidean space minimize the mean squared acceleration among all curves interpolating a given set of data points. We extend this observation to the Riemannian manifold of discrete shells in which the associated metric measures both bending and membrane distortion. Our generalization replaces the acceleration with the covariant derivative of the velocity. We introduce an effective time-discretization for this novel paradigm for navigating shell space. Further transferring this concept to the space of triangular surface descriptors-edge lengths, dihedral angles, and triangle areas-results in a simplified interpolation method with high computational efficiency
Erinnerung als zweite Natur? Die Walser-Bubis-Debatte, die Regierung Schröder und die Utopie einer „dritten Natur“
No full textGlobal impact distribution of asteroids and affected population
No full textWhich nations should be concerned about asteroid impacts? 261 impact corridors were calculated based on orbital data and impact probabilities of observed asteroids that could impact the Earth before 2100. The corridors, in the form of impact probability distributions were projected onto the Earth map. The cumulative impact probability distribution was combined with the Earth population producing a risk map to identify nations that should be concerned about the asteroid threat. The 40 nations that experience highest risk were identified. Results show that population size correlates strongly with impact risk and highlight the dilemma of small developing nations: they experience a disproportionally high risk relative to population but do not have the resources to mitigate the threat. The results emphasize the need for international cooperation to address the asteroid threat. Developed nations need to take the lead on asteroid discovery and mitigation on behalf of the rest of the world
Monitoring the global asteroid impact risk
No full textESA’s asteroid risk list contains all known asteroids that have a non-zero chance of colliding with the Earth in the future. The possible impact locations of the asteroids in the list with a minimum diameter of 30 m were calculated. To this end, the freely available software OrbFit was utilized to find orbit solutions for each asteroid that result in a future collision with the Earth. These orbit solutions are called virtual impactors (VIs). Subsequently, the Asteroid Risk Mitigation Optimization and Research (ARMOR) tool was used to determine the impact locations for each VI taking into account orbit solution uncertainty and global impact probability. The resulting 261 impact corridors were visualized on a global map. Furthermore, the impact data were combined with Earth population data to determine the risk of direct asteroid impacts that each nation faces until 2100. These data are the global asteroid risk distribution based on observed asteroids as is known today. A ranking of the countries that exhibit highest risk was produced showing their relative risk with respect to the global risk. It becomes clear that population size is a good proxy for relative risk. Each nation should raise public awareness about the asteroid hazard and should include the asteroid threat in their natural disaster response planning. Physical impact effects are introduced into the analysis. This expands the validity of the results beyond the previously considered relative risk and allows the estimation of the future absolute risk (expected casualties) that the currently known asteroids pose to the populations of the Earth. The alteration of the results based on the introduction of physical impact effects is discussed
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