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
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Your Inputs:
- Distance from Impact: 500.00 km ( = 311.00 miles )
- Projectile diameter: 370.00 meters ( = 1210.00 feet )
- Projectile Density: 4328 kg/m3
- Impact Velocity: 868.00 km per second ( = 539.00 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
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Energy:
- Energy before atmospheric entry: 4.32 x 1022 Joules = 1.03 x 107 MegaTons TNT
- The average interval between impacts of this size somewhere on Earth during the last 4 billion years is 2.8 x 107years
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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.
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Atmospheric Entry:
- The projectile begins to breakup at an altitude of 104000 meters = 342000 ft
- The projectile reaches the ground in a broken condition. The mass of projectile strikes the surface at velocity 859 km/s = 533 miles/s
- The energy lost in the atmosphere is 9.17 x 1020 Joules = 2.19 x 105 MegaTons.
- The impact energy is 4.23 x 1022 Joules = 1.01 x 107MegaTons.
- The larger of these two energies is used to estimate the airblast damage.
- The broken projectile fragments strike the ground in an ellipse of dimension 0.505 km by 0.505 km
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Crater Dimensions:
- What does this mean?
- Crater shape is normal in spite of atmospheric crushing; fragments are not significantly dispersed.
- Transient Crater Diameter:
34.7 km ( = 21.6 miles )
- Transient Crater Depth: 12.3 km ( = 7.62 miles )
- Final Crater Diameter:
55.4 km ( = 34.4 miles )
- Final Crater Depth: 991 meters ( = 3250 feet )
- The crater formed is a complex crater.
- The volume of the target melted or vaporized is 377 km3 = 90.4 miles3
- Roughly half the melt remains in the crater, where its average thickness is 398 meters ( = 1310 feet ).
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Thermal Radiation:
- What does this mean?
- Time for maximum radiation: 81.2 milliseconds after impact
- Visible fireball radius: 50.1 km ( = 31.1 miles )
- The fireball appears 22.8 times larger than the sun
- Thermal Exposure: 5.23 x 107 Joules/m2
- Duration of Irradiation: 15.1 minutes
- Radiant flux (relative to the sun): 57.7
- Effects of Thermal Radiation:
Clothing ignites
Much of the body suffers third degree burns
Newspaper ignites
Plywood flames
Deciduous trees ignite
Grass ignites
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Seismic Effects:
- What does this mean?
The major seismic shaking will arrive approximately 1.67 minutes after impact.- Richter Scale Magnitude: 9.3
- Mercalli Scale Intensity at a distance of 500 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 well-built ordinary structures; considerable damage in poorly built or badly designed structures; some chimneys broken.
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Ejecta:
- What does this mean?
The ejecta will arrive approximately 5.57 minutes after the impact.- At your position there is a fine dusting of ejecta with occasional larger fragments
- Average Ejecta Thickness: 10.4 cm ( = 4.08 inches )
- Mean Fragment Diameter: 5.17 mm ( = 2.04 tenths of an inch )
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Air Blast:
- What does this mean?
The air blast will arrive approximately 25.3 minutes after impact.- Peak Overpressure: 118000 Pa = 1.18 bars = 16.8 psi
- Max wind velocity: 196 m/s = 439 mph
- Sound Intensity: 101 dB (May cause ear pain)
- Damage Description:
Multistory wall-bearing buildings will collapse.
Wood frame buildings will almost completely collapse.
Highway truss bridges will suffer substantial distortion of bracing.
Glass windows will shatter.
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.
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