Earth Impact Effects Program

[M@ciek]

Znacie Earth Impact Effects Program?

Przypomniałem sobie o ciekawej aplikacji webowej wyliczającej efekty uderzenia obiektu o Ziemię czytając o asteroidzie 2004 BL86. Działa na wyobaźnię

 

Link: http://impact.ese.ic.ac.uk/ImpactEffects/

 

Dla przykładu wpisując przybliżone dane dot. asteroidy 2004 BL86 mającej uderzyć o powierzchnię Ziemi przy założeniach, że jesteśmy 150 km od miejsca uderzenia i asteroida:

• ma 650 m średnicy
• jest gęstą skałą (gęstość = 3000 km/m^3)
• porusza się 20 km/s (nie znalazłem wartości, strzalam)
• uderza pod kątem 45 stopni
• uderza w podłoże ze skał osadowych

okazuje się, że powstanie olbrzymi krater (średnica ok. 10 km) i w promieniu 150 km ciągle będzie niebezpiecznie bezpośrednio w trakcie uderzenia.

 

 

Your Inputs:

• Distance from Impact: 150.00 km ( = 93.20 miles )
• Projectile diameter: 650.00 meters ( = 2130.00 feet )
• Projectile Density: 3000 kg/m³
• Impact Velocity: 20.00 km per second ( = 12.40 miles per second )
• Impact Angle: 45 degrees
• Target Density: 2500 kg/m³
• Target Type: Sedimentary Rock

Energy:

• Energy before atmospheric entry: 8.63 x 10¹⁹ Joules = 2.06 x 10⁴ MegaTons TNT
• The average interval between impacts of this size somewhere on Earth during the last 4 billion years is 2.3 x 10⁵years

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 19.8 km/s = 12.3 miles/s
• The impact energy is 8.42 x 10¹⁹ Joules = 2.01 x 10⁴MegaTons.
• The broken projectile fragments strike the ground in an ellipse of dimension 1.22 km by 0.863 km

Crater Dimensions:

 

• Crater shape is normal in spite of atmospheric crushing; fragments are not significantly dispersed.
• Transient Crater Diameter: 8.08 km ( = 5.02 miles )
• Transient Crater Depth: 2.86 km ( = 1.77 miles )
• Final Crater Diameter: 10.7 km ( = 6.62 miles )
• Final Crater Depth: 603 meters ( = 1980 feet )
• The crater formed is a complex crater.
• The volume of the target melted or vaporized is 0.53 km³ = 0.127 miles³
• Roughly half the melt remains in the crater, where its average thickness is 10.3 meters ( = 33.9 feet ).

Thermal Radiation:

• Time for maximum radiation: 444 milliseconds after impact
• Visible fireball radius: 7 km ( = 4.35 miles )
• The fireball appears 10.6 times larger than the sun
• Thermal Exposure: 1.33 x 10⁶ Joules/m²
• Duration of Irradiation: 1.9 minutes
• Radiant flux (relative to the sun): 11.7
• Effects of Thermal Radiation:

• Much of the body suffers second degree burns
• Deciduous trees ignite

Seismic Effects:

• The major seismic shaking will arrive approximately 30 seconds after impact.
• Richter Scale Magnitude: 7.5
• Mercalli Scale Intensity at a distance of 150 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 2.96 minutes after the impact.
• At your position there is a fine dusting of ejecta with occasional larger fragments
• Average Ejecta Thickness: 1.13 cm ( = 0.444 inches )
• Mean Fragment Diameter: 2.3 cm ( = 0.906 inches )

Air Blast:

• The air blast will arrive approximately 7.58 minutes after impact.
• Peak Overpressure: 22700 Pa = 0.227 bars = 3.22 psi
• Max wind velocity: 48.9 m/s = 109 mph
• Sound Intensity: 87 dB (Loud as heavy traffic)
• Damage Description:

• Glass windows will shatter.
  
  About 30 percent of trees blown down; remainder have some branches and leaves blown off.

 

 

Link do wyników: http://impact.ese.ic.ac.uk/cgi-bin/crater.cgi?dist=150&distanceUnits=1&diam=650&diameterUnits=1&pdens=&pdens_select=3000&vel=20&velocityUnits=1&theta=45&wdepth=&wdepthUnits=1&tdens=2500