Welcome to the Earth Impact Effects Program: an easy-to-use, interactive web site for estimating the regional environmental consequences of an impact on Earth. This program will estimate the ejecta distribution, ground shaking, atmospheric blast wave, and thermal effects of an impact as well as the size of the crater produced.

Please enter values in the boxes below to describe your impact event of choice and your distance away. Then click "Calculate Effects" to learn about the environmental consequences.

- Please re-enter the following items:
- Distance from Impact
- Projectile Diameter
- Projectile Density
- Impact Velocity
- Impact Angle
- Target Density

Click here for a pdf document that details the observations, assumptions, and equations upon which this program is based. It describes our approach to quantifying the important impact processes that might affect the people, buildings, and landscape in the vicinity of an impact event and discusses the uncertainty in our predictions. The processes included are: atmospheric entry, impact crater formation, fireball expansion and thermal radiation, ejecta deposition, seismic shaking, and the propagation of the atmospheric blast wave.

Recent improvements in the airblast calculation are described here.

Earth Impact Effects Program Copyright 2004, Robert Marcus, H.J. Melosh, and G.S. Collins

These results come with ABSOLUTELY NO WARRANTY