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: 2.00 km ( = 1.24 miles )
 Projectile diameter: 100.00 meters ( = 328.00 feet )
 Projectile Density: 3000 kg/m^{3}
 Impact Velocity: 20.00 km per second ( = 12.40 miles per second )
 Impact Angle: 90 degrees
 Target Density: 27509 kg/m^{3}
 Target Type: Crystalline Rock

Energy:
 Energy before atmospheric entry: 3.14 x 10^{17} Joules = 7.50 x 10^{1} MegaTons TNT
 The average interval between impacts of this size somewhere on Earth during the last 4 billion years is 6.0 x 10^{3}years

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 56600 meters = 186000 ft
 The projectile reaches the ground in a broken condition. The mass of projectile strikes the surface at velocity 14 km/s = 8.7 miles/s
 The impact energy is 1.54 x 10^{17} Joules = 3.69 x 10^{1}MegaTons.
 The broken projectile fragments strike the ground in an ellipse of dimension 0.413 km by 0.413 km

Crater Dimensions:
 What does this mean?
 Crater shape is normal in spite of atmospheric crushing; fragments are not significantly dispersed.
 Transient Crater Diameter:
814 meters ( = 2670 feet )
 Transient Crater Depth: 288 meters ( = 944 feet )
 Final Crater Diameter:
1.02 km ( = 0.632 miles )
 Final Crater Depth: 217 meters ( = 710 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 100 meters ( = 329 feet ).
 The volume of the target melted or vaporized is 0.00137 km^{3} = 0.000329 miles^{3}
 Roughly half the melt remains in the crater

Thermal Radiation:
 What does this mean?
 At this impact velocity ( < 15 km/s), little vaporization occurs; no fireball is created, therefore, there is no thermal radiation damage.

Seismic Effects:
 What does this mean?
The major seismic shaking will arrive approximately 400 milliseconds after impact.  Richter Scale Magnitude: 5.6
 Mercalli Scale Intensity at a distance of 2 km:
VI. Felt by all, many frightened. Some heavy furniture moved; a few instances of fallen plaster. Damage slight.
VII. Damage negligible in buildings of good design and construction; slight to moderate in wellbuilt ordinary structures; considerable damage in poorly built or badly designed structures; some chimneys broken.

Ejecta:
 What does this mean?
The ejecta will arrive approximately 20.2 seconds after the impact.  At your position there is a fine dusting of ejecta with occasional larger fragments
 Average Ejecta Thickness: 49 cm ( = 19.3 inches )
 Mean Fragment Diameter: 191 meters ( = 625 feet )

Air Blast:
 What does this mean?
The air blast will arrive approximately 6.06 seconds after impact.  Peak Overpressure: 2.19e+06 Pa = 21.9 bars = 311 psi
 Max wind velocity: 1160 m/s = 2600 mph
 Sound Intensity: 127 dB (Dangerously Loud)
 Damage Description:
Multistory wallbearing buildings will collapse.
Wood frame buildings will almost completely collapse.
Multistory steelframed officetype buildings will suffer extreme frame distortion, incipient collapse.
Highway truss bridges will collapse.
Highway girder bridges will collapse.
Glass windows may shatter.
Glass windows will shatter.
Cars and trucks will be largely displaced and grossly distorted and will require rebuilding before use.
Up to 90 percent of trees blown down; remainder stripped of branches and leaves.
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