Impact Effects

Gareth Collins, Robert Marcus, and H. Jay Melosh

Please note: the results below are estimates based on current (limited) understanding of the impact process and come with large uncertainties; they should be used with caution, particularly in the case of peculiar input parameters. All values are given to three significant figures but this does not reflect the precision of the estimate. For more information about the uncertainty associated with our calculations and a full discussion of this program, please refer to this article

Click each effect button (e.g. "Crater") to see the extent of each impact effect!

Your Inputs:

Projectile diameter: 26.00 km ( = 16.10 miles )

Projectile Density: 2300 kg/m³

Impact Velocity: 55.00 km per second ( = 34.20 miles per second )

Impact Angle: 80 degrees

Target Density: 2750 kg/m³

Target Type: Crystalline Rock

Energy:

Energy before atmospheric entry: 3.20 x 10²⁵ Joules = 7.65 x 10⁹ MegaTons TNT

The average interval between impacts of this size somewhere on Earth during the last 4 billion years is 4.5 x 10⁹years

Major Global Changes:

The Earth is not strongly disturbed by the impact and loses negligible mass.

The impact does not make a noticeable change in the tilt of Earth's axis (< 5 hundreths of a degree).

Depending on the direction and location of impact, the collision may cause a change in the length of the day of up to 15.8 milliseconds.

The impact does not shift the Earth's orbit noticeably.

Crater Dimensions:

What does this mean?

Transient Crater Diameter: 223 km ( = 138 miles )

Transient Crater Depth: 78.8 km ( = 49 miles )

Final Crater Diameter: 453 km ( = 281 miles )

Final Crater Depth: 1.86 km ( = 1.16 miles )

The crater formed is a complex crater.

The volume of the target melted or vaporized is 280000 km³ = 67300 miles³

Roughly half the melt remains in the crater, where its average thickness is 7.18 km ( = 4.46 miles ).

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.