Users Manual: Crater Sizes from Explosions or Impacts
by
Keith A. Holsapple
11/26/03

I. Introduction

This is an application that allows you to determine the crater size, shape and other features for both explosion and impact craters for terrestrial and solar-system cratering, and for a very wide range of conditions: from lab-sized to 100's of kilometer basins.

It includes simple excavation craters in either of the strength or gravity-dominated regimes, and also includes the large complex craters seen on the moon and other solar system bodies.

It is based on the extensive cratering database at http://keith.aa.washington.edu/craterdata/index.html synthesized using the scaling methods developed over the last 20 years by Keith Holsapple, Robert Schmidt and Kevin Housen, as indicated in the reference list below.

To use it, you first chooses the "Explosions" or the "Impacts" tabs at the top. Then the conditions describing the event are made, with many preset conditions indicated. The results are continuously updated at the bottom as the choices are made. For the larger complex craters, additional boxes appear at the bottom with the complex crater sizes indicated.

Each input has a choice of units to use, and when the units are changed, the values in the input boxes are converted automatically. (So you can just use it as a units conversion program..)

Alternatively, for impacts you can choose the crater diameter (excavation or complex), and for all other parameters fixed, the program will solve for the source size (impactor diameter of explosion weight) that gives the desired size.

The scaling underlying these calculations are based predominantly on the known field and laboratory experimental data for explosions and impacts. The complete database of over 1500 events can be accessed by clicking:

Code calculations of cratering are becoming very popular, and this application provides a way to test and calibrate results against known cases. However, because of the extreme complexity of modelling the material behavior of rocks and soils, code calculation results should be (at least in the view of this author, if not in the view of the calculators!) considered highly uncertain; so they have not played any significant role in choosing the scaling rules used in this tool.

This has been tested in current Macintosh versions of Explorer, AOL, Netscape and Safari. It looks the best in Safari, but worked in all and I expect it should work in Windows versions. It looks somewhat klutzy in Explorer and especially in Netscape.

If there are any problems please contact holsapple@aa.washington.edu

The equations and details of the underlying calculations are in a pdf file:   Theory and Equations for Crater Scaling

References:

  • "The Scaling of Impact Processes in Planetary Sciences", Annual Reviews of Earth and Planetary Sciences 21 pp333-373, 1993 PDF Version
  • "The size of complex craters", Lunar and Planetary Science Conference XXIV, 1993 PDF Version
  • Holsapple, K.A., "The Scaling of Impact Phenomenon", Intl. J. Impact Engr., 5, 343-355, 1987.
  • Holsapple, K.A. and R.M. Schmidt, "Point-Source Solutions and Coupling Parameters in Cratering Mechanics", J. Geophys. Res., Vol. 92, No. B7, 6350-6376, 1987.
  • Holsapple, K.A. and R.M. Schmidt, "On the Scaling of Crater Dimensions 2. Impact Processes", J. Geophy. Res., 87, No. B3, 1849-1870, March 1982.
  • Schmidt, R.M. and K.A. Holsapple, "Theory and Experiments on Centrifuge Cratering", J. Geophys. Res. 85, 235-252, January, 1980.
  • Holsapple, K.A., "Underground Cavities by Nuclear Explosions: The Implications of Point-Source Solutions for Geological Materials", (Abstract) 7th Symposium on the Containment of Underground Nuclear Explosions, 1993.
  • Holsapple, K.A., "The Search for the Scaling Laws of Impact Cratering: Recent Numerical Results", Lunar and Planetary Science XVII, Houston, TX, March 1986.
  • Holsapple, K.A., "On the Existence and Implications of Coupling Parameters in Cratering Mechanics", Lunar and Planetary Science XIV, March 1983.