Earth Impact Effects Program

Robert Marcus, H. Jay Melosh, and Gareth Collins

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

Your Inputs:

Distance from Impact: 100.00 meters ( = 328.00 feet )
Projectile diameter: 43.00 meters ( = 141.00 feet )
Projectile Density: 8000 kg/m3
Impact Velocity: 9.50 km per second ( = 5.90 miles per second )
Impact Angle: 90 degrees
Target Density: 2500 kg/m3
Target Type: Sedimentary Rock


Energy before atmospheric entry: 1.50 x 1016 Joules = 3.59 MegaTons TNT
The average interval between impacts of this size somewhere on Earth during the last 4 billion years is 1.4 x 103years

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 4740 meters = 15500 ft
The projectile reaches the ground in a broken condition. The mass of projectile strikes the surface at velocity 9.06 km/s = 5.63 miles/s
The impact energy is 1.37 x 1016 Joules = 3.26 MegaTons.
The broken projectile fragments strike the ground in an ellipse of dimension 0.0778 km by 0.0778 km

Crater Dimensions:

What does this mean?

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

Transient Crater Diameter: 1.07 km ( = 0.666 miles )
Transient Crater Depth: 379 meters ( = 1240 feet )

Final Crater Diameter: 1.34 km ( = 0.833 miles )
Final Crater Depth: 285 meters ( = 936 feet )
The crater formed is a simple crater

The floor of the crater is underlain by a lens of broken rock debris (breccia) with a maximum thickness of 132 meters ( = 434 feet ).
At this impact velocity ( < 12 km/s), little shock melting of the target occurs.


What does this mean?

Most ejecta is blocked by Earth's atmosphere