What is the Minimum Size of a Near Earth Object Impactor which Can Cause Ground Damage?
Abstract
The impact danger from Near Earth Objects (NEOs) has been examined in detail for several decades. However, emphasis has tended to focus on quantifying impact effects from the largest, but most infrequent, NEO impacts. The Feb 15, 2013 Chelyabinsk airburst has drawn attention to the extreme small end ( 10 m) of the impactor spectrum. Window blast damage is the dominant damage modality at the smallest sizes (ignoring kinetic effects from direct meteorite impacts on ground objects) as seen at Chelyabinsk. This leads naturally to the question: what is the smallest NEO impactor for which we can expect economically significant window damage due to airblast? Clearly, this is smaller than Chelyabinsk ( 0.5 MT) but how much smaller? Here we attempt to answer this question by first estimating the overpressure needed to damage windows at a level causing economically significant window breakage in urban areas. We then estimate the areal footprint of overpressure exceeding these limits caused by airbursts of different energies and impact geometries. We use the Triggered Progressive Fragmentation (TPFM) entry model of ReVelle (2005) conditioned by empirical limits on fragmentation height and energy to generate physically realistic height-energy deposition profiles. We will present estimates of the threshold limits for the total energy, airburst height and entry angle from these simulations which may be expected to cause significant window damage if an airburst occurs over an urban area.
- Publication:
-
AAS/Division for Planetary Sciences Meeting Abstracts #50
- Pub Date:
- October 2018
- Bibcode:
- 2018DPS....5050502B