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: 161.00 km ( = 100.00 miles )
- Projectile diameter: 200.00 meters ( = 656.00 feet )
- Projectile Density: 3000 kg/m3
- Impact Velocity: 20.00 km per second ( = 12.40 miles per second )
- Impact Angle: 45 degrees
- Target Density: 2750 kg/m3
- Target Type: Crystalline Rock
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Energy:
- Energy before atmospheric entry: 2.51 x 1018 Joules = 6.00 x 102 MegaTons TNT
- The average interval between impacts of this size somewhere on Earth during the last 4 billion years is 4.1 x 104years
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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 56600 meters = 186000 ft
- The projectile reaches the ground in a broken condition. The mass of projectile strikes the surface at velocity 17.4 km/s = 10.8 miles/s
- The energy lost in the atmosphere is 6.13 x 1017 Joules = 1.46 x 102 MegaTons.
- The impact energy is 1.90 x 1018 Joules = 4.54 x 102MegaTons.
- 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 0.851 km by 0.602 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:
2.95 km ( = 1.83 miles )
- Transient Crater Depth: 1.04 km ( = 0.648 miles )
- Final Crater Diameter:
3.42 km ( = 2.12 miles )
- Final Crater Depth: 428 meters ( = 1400 feet )
- The crater formed is a complex crater.
- The volume of the target melted or vaporized is 0.012 km3 = 0.00287 miles3
- Roughly half the melt remains in the crater
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Thermal Radiation:
- What does this mean?
- Time for maximum radiation: 142 milliseconds after impact
- Visible fireball radius: 443 meters ( = 1450 feet )
- The fireball appears 0.625 times larger than the sun
- Thermal Exposure: 3.09 x 103 Joules/m2
- Duration of Irradiation: 32.2 seconds
- Radiant flux (relative to the sun): 0.0959
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Seismic Effects:
- What does this mean?
The major seismic shaking will arrive approximately 32.2 seconds after impact.- Richter Scale Magnitude: 6.4
- Mercalli Scale Intensity at a distance of 161 km:
IV. Felt indoors by many, outdoors by few during the day. At night, some awakened. Dishes, windows, doors disturbed; walls make cracking sound. Sensation like heavy truck striking building. Standing motor cars rocked noticeably.
V. Felt by nearly everyone; many awakened. Some dishes, windows broken. Unstable objects overturned. Pendulum clocks may stop.
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Ejecta:
- What does this mean?
The ejecta will arrive approximately 3.07 minutes after the impact.- At your position there is a fine dusting of ejecta with occasional larger fragments
- Average Ejecta Thickness: 162 microns ( = 6.39 thousandths of an inch )
- Mean Fragment Diameter: 5.91 mm ( = 2.33 tenths of an inch )
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Air Blast:
- What does this mean?
The air blast will arrive approximately 8.13 minutes after impact.- Peak Overpressure: 3190 Pa = 0.0319 bars = 0.453 psi
- Max wind velocity: 7.42 m/s = 16.6 mph
- Sound Intensity: 70 dB (Loud as heavy traffic)
- Damage Description:
Glass windows may shatter.
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