Teh Newz posted:

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The 460 foot ball of rock

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Quote:

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Distance from Impact: 10.00 km ( = 6.21 miles )

Projectile diameter: 140.00 meters ( = 460.00 feet )

Projectile Density: 3000 kg/m3

Impact Velocity: 15.60 km per second ( = 9.71 miles per second )

Impact Angle: 45 degrees

Target Density: 2500 kg/m3

Target Type: Sedimentary Rock


Energy:

Energy before atmospheric entry: 5.29 x 1017 Joules = 1.26 x 10^2 MegaTons TNT

The average interval between impacts of this size somewhere on Earth during the last 4 billion years is 1.5 x 104years


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 52700 meters = 173000 ft

The projectile reaches the ground in a broken condition. The mass of projectile strikes the surface at velocity 10.9 km/s = 6.79 miles/s

The impact energy is 2.59 x 1017 Joules = 6.19 x 10^1 MegaTons.

The broken projectile fragments strike the ground in an ellipse of dimension 0.82 km by 0.58 km


Crater Dimensions:

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


Transient Crater Diameter: 1.88 km ( = 1.17 miles )

Transient Crater Depth: 666 meters ( = 2180 feet )


Final Crater Diameter: 2.35 km ( = 1.46 miles )

Final Crater Depth: 501 meters ( = 1640 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 232 meters ( = 762 feet ).

At this impact velocity ( < 12 km/s), little shock melting of the target occurs.


Thermal Radiation:


At this impact velocity ( < 15 km/s), little vaporization occurs; no fireball is created, therefore, there is no thermal radiation damage.


Seismic Effects:


The major seismic shaking will arrive approximately 2 seconds after impact.

Richter Scale Magnitude: 5.8

Mercalli Scale Intensity at a distance of 10 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.


Ejecta:


The ejecta will arrive approximately 45.2 seconds after the impact.

At your position there is a fine dusting of ejecta with occasional larger fragments

Average Ejecta Thickness: 11.2 cm ( = 4.41 inches )

Mean Fragment Diameter: 6.35 meters ( = 20.8 feet )


Air Blast:


The air blast will arrive approximately 30.3 seconds after impact.

Peak Overpressure: 98600 Pa = 0.986 bars = 14 psi

Max wind velocity: 171 m/s = 383 mph

Sound Intensity: 100 dB (May cause ear pain)

Damage Description:


Multistory wall-bearing buildings will collapse.


Wood frame buildings will almost completely collapse.


Glass windows will shatter.


Up to 90 percent of trees blown down; remainder stripped of branches and leaves.

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