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

Select Impact Effect:

Your Inputs:

Projectile diameter: 370.00 meters ( = 1210.00 feet )
Projectile Density: 4328 kg/m3
Impact Velocity: 94000.00 km per second ( = 58400.00 miles per second ) (Your chosen velocity is higher than the maximum for an object orbiting the sun)
Impact Angle: 90 degrees
Target Density: 2500 kg/m3
Target Type: Sedimentary Rock

Energy:

Energy before atmospheric entry: -nan x 10-nan Joules = 1.21 x 1011 MegaTons TNT
The average interval between impacts of this size is longer than the Earth's age.
Such impacts could only occur during the accumulation of the Earth, between 4.5 and 4 billion years ago.

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

Atmospheric Entry:

The projectile begins to breakup at an altitude of 179000 meters = 588000 ft
The projectile reaches the ground in a broken condition. The mass of projectile strikes the surface at velocity 93000 km/s = 57800 miles/s
The impact energy is 4.96 x 1026 Joules = 1.19 x 1011MegaTons.
The broken projectile fragments strike the ground in an ellipse of dimension 0.505 km by 0.505 km

Crater Dimensions:

What does this mean?


Crater shape is normal in spite of atmospheric crushing; fragments are not significantly dispersed.

Transient Crater Diameter: 273 km ( = 169 miles )
Transient Crater Depth: 96.4 km ( = 59.9 miles )

Final Crater Diameter: 569 km ( = 353 miles )
Final Crater Depth: 2 km ( = 1.24 miles )
The final crater is replaced by a large, circular melt province.
The volume of the target melted or vaporized is 4.42e+06 km3 = 1.06e+06 miles3
Melt volume = 1.66 times the crater volume
At this size, the crater forms in its own melt pool.


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.






Earth Impact Effects Program Copyright 2004, Robert Marcus, H.J. Melosh, and G.S. Collins
These results come with ABSOLUTELY NO WARRANTY