Impact Effects

Damage Map Version

Gareth Collins, Robert Marcus, and H. Jay Melosh

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 a location on Earth to impact, then enter values in the boxes below to describe your impact of choice. Select the impact effect you are interested in and rhen click "Display Impact Effects" to see the damage zone!

Please re-enter the following items:
Latitude
Note: Latitude must be between 0 (equator) and 90 degrees (pole); use negative values for Southern latitudes.
Longitude
Note: Longitude must be between 0 and 180 degrees; use positive values for eastern longitudes and negative values for western longitudes.
Projectile Diameter
Projectile Density
Impact Velocity
Impact Angle
Target Type

Location of Impact

and or or

Enter Impact Parameters

Projectile Parameters

Projectile Diameter (in meters) or

Projectile Density (in kg/m3) or

Impact Parameters

Impact Velocity (in km/s)

This is the velocity of the projectile before it enters the atmosphere. The minimum impact velocity on Earth is 11 km/s. Typical impact velocities are 17 km/s for asteroids and 51 km/s for comets. The maximum Earth impact velocity for objects orbiting the sun is 72 km/s.

Impact Angle (in degrees)

The impact angle is measured from a plane tangent to the impact surface. This angle is 90 degrees for a vertical impact. The most probable angle of impact is 45 degrees.

Target Parameters

Target Type
Water of depth:
Sedimentary Rock
Crystalline Rock




Tell me more...

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