NEO Collisions with Earth: The Impact Effects Knowledgebase
Abstract
Although impacts of km-sized NEOs cause severe damage (up to mass extinction), these events are not as frequent as impacts of smaller (20-200 m) objects, which can cause significant problems if they hit critical locations (such as densely populated areas, nuclear and chemical facilities). Modelling of such encounters may help to predict the environmental consequences of these events prior to a real impact. Simulation tools, so-called shock-physics codes (e.g. SOVA [1]), allow for detailed quantitative modelling of the processes during the atmospheric entry, the potential break-up, and ground effects of cosmic bodies ranging from a few meters up to 300 m. Such tools yield accurate predictions of the consequences if the entry parameters are well known, but have a high demand on computational resources. Tools using simplified analytical approaches (e.g. pancake model [2,3] and the separate fragment model [4,5]) yield preliminary results quickly, but strongly depend on poorly known internal parameters. A tool that is accurate enough to allow predictions, fast enough to check an influence of unknown inputs, and is easy to use is highly desirable for ESA's SSA-NEO segment to release impact warnings and inform emergency response agencies.
In this study, we combine both approaches to generate a knowledgebase for events with different impact velocities, impact angles, impactor sizes, and impactor material properties to predict the consequences of an impact event, such as overpressure, wind speed, and irradiation on the ground. In the case of cratering events we estimate the crater size and the ejecta distribution of the single or, in the case of a strewn field, multiple craters and their distribution. Previous benchmark studies and comparison with real events (e.g. Chelyabinsk, Tunguska) are used to analyse the accuracy of these predictions. We also define the entry parameter space in which analytical or full-scale modelling are more efficient. We acknowledge the funding by ESA SSA-NEO, contract code P3-NEO-VIII. [1] Shuvalov V.V. (1999) ShockWaves 9, 381-390. [2] Chyba C.F., Thomas P.J. and Zahnle K.J. (1993) Nature 361, 40-44. [3] Ceplecha Z., Spurný P., Borovicka J. and Keclìková J. (1993) A&A 279, 615-626. [4] Passey Q. and Melosh H.J. (1980) Icarus 42, 211-233. [5] Artemieva N.A. and Shuvalov V.V. (2001) JGR 106, 3297-3310.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMNH54B..04L
- Keywords:
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- 4301 Atmospheric;
- NATURAL HAZARDS;
- 4314 Mathematical and computer modeling;
- NATURAL HAZARDS;
- 6008 Composition;
- PLANETARY SCIENCES: COMETS AND SMALL BODIES;
- 6022 Impact phenomena;
- PLANETARY SCIENCES: COMETS AND SMALL BODIES