960 research outputs found
Asteroid Impact Effect Dominance Dataset
No full textSimulation results supporting the publication: Asteroid impact effects and their immediate hazards for human populations, published in Geophysical Research Letters</span
Global asteroid risk analysis
No full textPotentially impacting asteroids were analysed for their impact risk on the Earth. To this end, the Asteroid Risk Mitigation Optimization and Research (ARMOR) tool is currently being developed. The tool’s modules are described and their validation is documented. Based on the asteroid ephemeris, the tool calculates the impact location probability distribution on the surface of the Earth (in the literature, occasionally referred to as risk corridor). NASA’s Near Earth Object (NEO) risk list served as the source for asteroid ephemerides. The Line of Variation (LOV) method was employed to find virtual impactors. While offering a simple and fast way of identifying virtual impactors, the method provides a low impactor identification rate. This is because the search space is tightly constricted to the LOV and thus excludes virtual impactors located elsewhere in the asteroid position uncertainty region. The method’s performance was evaluated and suggestions for improvements are provided. Application of the tool showed that the asteroid threat is global in nature: impact locations were distributed widely over the Earth’s surface. The global asteroid risk was estimated by combining the impact location probability distribution with Earth population data. The identification of high risk regions lead to a discussion about the dynamics of the risk associated with asteroids. The future response to an asteroid threat will depend on the risk that the asteroid poses to the population. The potential applicability of ARMOR as a decision-support tool for responding to the asteroid threat is outlined. The work is supported by the Marie Curie Initial Training Network Stardust, FP7-PEOPLE-2012-ITN, Grant Agreement 31718
Michael Rodriguez interviews author Paul Clemens
No full textAuthor Paul Clemens talks about his book "Made in Detroit," the genre of memoir, and writing about race. Clemens is interviewed by Michigan State University Librarian Michael Rodriguez for the MSU Libraries' Michigan Writers Series. Held in the MSU Main Library
Asteroid impact risk
No full textAsteroid impacts are a hazard to human populations. A method to assess the impact risk of hazardous asteroids was developed in this work, making use of the universal concept of risk culminating in the Asteroid Risk Mitigation Optimization and Research (ARMOR) tool. Using this tool, the global spatial risk distribution of a threatening asteroid can be calculated and expressed in the units of expected casualties (= fatalities). Risk distribution knowledge enables disaster managers to plan for a potential asteroid impact through identification of high risk regions and estimation of total risk as a scalar value. Expressing the risk in terms of expected casualties would allow the placement of the asteroid threat on the same scale as other human hazards. Thus, this unit provides an accessible way of defining thresholds for asteroid threat response protocols, of communicating the threat utilizing a new hazard scale, and of allocating adequate resources to address the hazard by comparison with other natural disasters. To accomplish risk estimation, vulnerability models were needed that relate the severity of impact effects (wind blast, overpressure shock, thermal radiation, cratering, seismic shaking, ejecta out-throw, and tsunami) on the human population and a novel comprehensive suite of such models were derived and presented. The need for high fidelity impact effect and vulnerability modelling, as opposed to a simplified, impact location based approach, for risk estimation of a specific asteroid threat was analysed and confirmed. Subsequently, the method of ARMOR was applied to asteroid 2015 RN35 to produce an example risk distribution output. Additional analysis shows that the general impact location distribution of asteroids is approximately uniform, confirming, for the first time, a common assumption made in planetary defense. Extensive global simulations were performed utilizing an artificial sample of 50,000 impactors with sizes up to 400m to identify which impact effects are most hazardous to the human population. Aerothermal effects are most hazardous while tsunamis only contribute moderately to the overall hazard. The average land impactor is an order of magnitude more dangerous than a similar water impactor and asteroids smaller than 50-60m (density ≈ 3100 kg/m3) are expected to airburst rather than reach the surface. Furthermore, the average loss estimate for asteroid impactors enables fast threat analysis of newly discovered asteroids and helps determine the asteroid size that contributes most to the residual asteroid impact risk. These results provide new insights to inform efficient preparation for a future asteroid threat. In the future, ARMOR can be used to perform on-ground risk driven asteroid detection mission design which would reduce risk of an incoming asteroid progressively and this is not accomplished with current methods
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
Asteroid Impact Risk Changes Due To Disruption By A Deflection Mission
No full textThis data is the basis for the analysis relating to impact risk analysis of asteroids following disruption by a deflection mission. In particular, these data describe Apophis scenarios
Author Paul Clemens reads from his book "Made in Detroit" at the Michigan Writers Series
No full textAuthor Paul Clemens reads from his book "Made in Detroit" and answers questions from the audience. The event is convened by Peter Berg, head of the Michigan State University Libraries' Special Collections. Part of the MSU Libraries' Michigan Writers Series. Held in the MSU Main Library
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
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
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