A Caltech Library Service

Giant impact-induced blow-off of primordial atmosphere

Ni, Sidao and Ahrens, Thomas J. (2005) Giant impact-induced blow-off of primordial atmosphere. In: Large Meteorite Impacts III. Special papers (Geological Society of America). No.384. Geological Society of America , Boulder, CO, pp. 427-432. ISBN 9780813723846.

Full text is not posted in this repository. Consult Related URLs below.

Use this Persistent URL to link to this item:


The surface motion from a large impact upon an attenuation-free fluid sphere was studied and numerically simulated. An analytic solution for the free-surface velocity shows that close to the source, the acoustic wave due to the free-surface interaction (a “quasi-surface wave”) is not separable from the direct wave. At >90°, the quasi-surface wave separates and has a larger amplitude than the direct body wave. Near the antipode the quasi-surface wave amplitude is much larger than the direct body wave and is comparable to the direct wave amplitude immediately near the source at 0°. The resulting solution covers both the wave interference range as defined in the asymptotic theory of near-surface wave propagation developed by Russian physicist V.S. Buldyrev reported in 1968, as well as in the geometric ray range. The geometric range theory was described in several papers in terms of multi-geometry reflection by R. Burridge, H. Jeffreys, and E.R. Lapwood in England in 1957 through 1963. For a large surface excitation (e.g., giant ∼10^(27) J impact) a portion of the atmosphere above a plane tangent to Earth at the impact point is launched to velocities greater than the escape velocity. The resulting antipodal free-surface velocity achieved is ∼1.9 km/s, which is sufficient to launch a comparable fraction of the atmosphere to escape.

Item Type:Book Section
Related URLs:
URLURL TypeDescription
Ni, Sidao0000-0003-2988-4850
Additional Information:© 2005 Geological Society of America. Accepted 9 August 2004. We warmly thank Hiroo Kanamori and Donald V. Helmberger for technical suggestions that made this project work. This paper has benefited from a helpful review of Jay Melosh and an anonymous reviewer. Research supported by NASA Goddard Grant NAG5-10198. This is contribution #8584, Division of Geological and Planetary Science, California Institute of Technology, Pasadena, California 91125.
Funding AgencyGrant Number
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Caltech Division of Geological and Planetary Sciences8584
Series Name:Special papers (Geological Society of America)
Issue or Number:384
Record Number:CaltechAUTHORS:20150202-103603719
Persistent URL:
Official Citation:Ni, S., and Ahrens, T.J., 2005, Giant impact-induced blow-off of primordial atmosphere, in Kenkmann, T., Hiirz, F., and Deutsch, A., eds., Large meteorite impacts III: Geological Society of America Special Paper 384, p. 427-432
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:54295
Deposited By: Tony Diaz
Deposited On:04 Feb 2015 17:32
Last Modified:10 Nov 2021 20:31

Repository Staff Only: item control page