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dc.contributor.advisorStrom, Robert G.en_US
dc.contributor.authorWood, David Allen
dc.creatorWood, David Allenen_US
dc.date.accessioned2013-05-09T09:36:59Z
dc.date.available2013-05-09T09:36:59Z
dc.date.issued2000en_US
dc.identifier.urihttp://hdl.handle.net/10150/289162
dc.description.abstractMagellan observed quasi-circular, apparently impact-related, radar albedo features on Venus. Pristine examples show dark regions centered within larger bright regions. Dark regions are interpreted as smooth and bright regions are interpreted as rough. Of the 518 features, 256 are centered on impact craters (crater haloes), 53 are centered upon small central disturbances (disrupted splotches), and the remaining 209 exhibit no central structure (craterless splotches). Most researchers interpret these features as airburst scars. Previous models of airburst formation only reproduced subsets of the observations. Models of splotch and halo formation were often mutually exclusive and no previous model connected them despite their similarities. I rectify this problem with a model that successfully reproduces 514 of the 518 patterns given appropriate airburst altitude and energy conditions combined with erosion. In my model, dark zones are pulverized rock, and bright zones are scoured surfaces. More complicated patterns are obtained with modification of the initial dark/bright pattern. Small impactors that do not penetrate the atmosphere cannot cause surface damage. Large impactors that penetrate the atmosphere without disruption create an impact crater without an associated airburst scar. Only intermediate-size impactors, partially or wholly disrupted in the near-surface zone, form airburst scars. Typical diameters for airburst scar-forming impactors are 200 meters--2 km for irons, 300 meters--3 km for stones, and >3 km for comets.
dc.language.isoen_USen_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.subjectGeophysics.en_US
dc.subjectPhysics, Astronomy and Astrophysics.en_US
dc.titleEffects of airbursts on the surface of Venusen_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
thesis.degree.grantorUniversity of Arizonaen_US
thesis.degree.leveldoctoralen_US
dc.identifier.proquest9983856en_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplinePlanetary Sciencesen_US
thesis.degree.namePh.D.en_US
dc.identifier.bibrecord.b40821985en_US
refterms.dateFOA2018-09-06T07:50:37Z
html.description.abstractMagellan observed quasi-circular, apparently impact-related, radar albedo features on Venus. Pristine examples show dark regions centered within larger bright regions. Dark regions are interpreted as smooth and bright regions are interpreted as rough. Of the 518 features, 256 are centered on impact craters (crater haloes), 53 are centered upon small central disturbances (disrupted splotches), and the remaining 209 exhibit no central structure (craterless splotches). Most researchers interpret these features as airburst scars. Previous models of airburst formation only reproduced subsets of the observations. Models of splotch and halo formation were often mutually exclusive and no previous model connected them despite their similarities. I rectify this problem with a model that successfully reproduces 514 of the 518 patterns given appropriate airburst altitude and energy conditions combined with erosion. In my model, dark zones are pulverized rock, and bright zones are scoured surfaces. More complicated patterns are obtained with modification of the initial dark/bright pattern. Small impactors that do not penetrate the atmosphere cannot cause surface damage. Large impactors that penetrate the atmosphere without disruption create an impact crater without an associated airburst scar. Only intermediate-size impactors, partially or wholly disrupted in the near-surface zone, form airburst scars. Typical diameters for airburst scar-forming impactors are 200 meters--2 km for irons, 300 meters--3 km for stones, and >3 km for comets.


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