Teh Newz posted:

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The 460 foot ball of rock

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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.