WEB-BASED PROGRAM FOR CALCULATING EFFECTS OF AN EARTH IMPACT.

Periodically, stories concerning the possibility of a large extraterrestrial impact on earth enter the mainstream media. During these times, both scientists and non-scientists alike become interested in determining the effects that this impact would cause on earth, often with a particular impact site and distance from impact in mind. For scientists, the trouble with determining these effects is merely the time it would take to find all of the equations and data necessary to calculate the effects. For non-scientists, these calculations are all but impossible. Presently, there is no reliable place where the interested person may obtain a clear and concise summary of the general effects created by an impact on earth. We currently maintain a popular crater diameter calculator online at http://www.lpl.arizona. edu/tekton/crater.html. This program uses scaling laws to derive crater size estimates from impact parameters such as impactor size, velocity and density. The goal of the Earth Impact Effects Program is to provide a similar, easy-to-use web-based program to calculate various pertinent environmental consequences of a given impact event on Earth at a specified distance away. So far, the environmental effects that we have considered are crater size, seismic effects (including Richter magnitude and damage assessment), and the thickness and average fragment size of the ejecta deposit. In the future, we intend to extend the program to include the effects of the shock wave and thermal radiation. In addition, the web page will include a description of our algorithm with citations to the scientific sources used. It is our intention for this program to be useful for not only casual users, but also those who require a deeper understanding of how the results were obtained.