An impact crater is the depression of more or less circular form of the collision of an object

on another of large enough size to make it not fully destroyed by the impact

The term is particularly used in astronomy to describe the result of the collision of celestial objects

(an asteroid or a comet impacting a planet for example)

Definitions

When the meteorite arrives on the ground it penetrates rapidly spraying under the enormous energy of the impact

The soil behaves like an elastic material - to its measurement - and sinking deeply while spraying and in fractured

After a few seconds the hole reached its maximum size it is the transient crater

Then the ground resumed his place is the bounce It remains at the end that a final crater whose shape depends on

the volume of basement vaporized and ejected from the residual compression in rocks the strength of the rebound

and landslides of land and eboulementsdes walls and spin-offs The final crater will put a few weeks

or months to stabilize until the erosion starts it

Nowadays most of the large craters are visible in their weathered form and you cant measure that an apparent crater

whose shape is more or less visible according to the degree of erosion refills in sediments or movements of the basement

During the rebound and when the size of the crater is sufficient the centre raises more than the surrounding area

kinda like a drop of water It forms a central uplift more or less important can go further back than the bottom of the crater

He then formed a central peak more or less pronounced

Note when the meteorite is large enough to pierce the crust and cause magmatic effusions

one speaks of crater and basin

IMPACTS ON EARTH

Impact shock resulting from the meeting of a projectile a body with another body

Project Name Client

Project No Prep By Date

Data of the object and the target

Mass of the object (kg) 10E+02

Mass (kg) 597E+24 Weigh in Newtons (ground level) 981088

Equatorial Radius (km) 6378137 Density of the object (kgm3) 5000

Polar Radius (km) 6356752 Diameter of the object (m) 10

calc g on surface level (mssup2) 981

Angle of impact (degree) 12000

Angle in radians (rad) 20944

Unknown

sedimential ground Speed at impact (ms) 20000 20000 kms

crystalline ground x 4750 Speed (kmh) 72000

[check one cell please]

Density of the target (kgm3) 3200

Kinetic Energy [joules] 2000E+10 2000E+04 mega-J Diameter of transition - Dsc (m) 4750 (lt default )

Kinetic Energy [calories] 4778E+09 4778E+03 mega-cal Diameter of the transient crater - Dtc (m) 31482

gt Depth of the transient crater (m) 11208

Kinetic energy [eqmass kgf] 2039E+09 2039E+06 tonnes-force Diameter of the crater - Dfr (m) 39352 (simple crater)

Kinetic energy [TNT tonne (s)] 4779E+00 4779E+03 kilo(s) TNT Height of the edges of the crater (m) 1128

Note by convention gt 1 kg of TNT = 106 calories = 4 185106J Height of the breccias of the crater (m) 3652

Final depth of the crater (m) 8684

Radius of the object (m) 1000

Volume (m3) 4189E+03

Density of the object (kgm3) 1000000

Mass (kg) 4189E+07

This is the distance between the top of the edges of the crater (ridge line)

Calculation of the mass of an object (spherical)

Results Estimate of the size of the crater

and the top of the breccia lens that covers the bottom of the crater

CALCULATION OF AN IMPACT ON EARTH

EARTH

Nature of the target ground (check a cell)

Two types of celestial objects can collide with our planet asteroids and comets

Asteroids are composed of rocks and metals and their density varies between 2000 and 8000 kgm3

For example Chondrite CM in density from 3400 to 3800 kgm3 (Mighei meteorite fallen on June 18 1889 in Ukraine)

Their speed at the entrance into the atmosphere is between 11 and 21 kms

Comets are primarily composed of ice Their density is between 500 and 1500 kgm3

and their speed between 30 and 72 kms

Other objects - not observed to date - can potentially collide with the Earth Its interstellar objects

their speed is greater than 72 kms (otherwise they would orbit around the Sun)

Because of their origin their nature and density are unknown

FORMULAS

Kinetic energy of the impact (Joules) Ec (J) = 12Mvsup2

with M mass of the car in kg and v is its velocity in ms Emitted energy by convention 1 kg of TNT = 106 calories = 4 185106J

Note 1 calorie (cal) = 41855 J The bomb dropped on Hiroshima in 1945 had a power

of approximately 15 kilotonnes (15 000 tonnes of TNT)

Dsc transitional transition diameter between simple craters and complex on Earth equal to

- when it does not know the nature of the target field gt 3200

- in a sedimentary field gt 2250

- in a crystalline field gt 4750

Diameter of a transient crater Dtc

Note all diameters depths thicknesses and heights

are expressed in m

r i density of the asteroid in kgm3 (and mj its mass in kg)

r c target density kgm3

fi diameter of the meteorite in m

ui speed of the meteorite at impact in ms

g acceleration due to gravity of the target (equal to 981 mss on average on Earth)

θ angle of impact the horizontal (for vertical impact θ = 90 deg)

Depth of the transient crater - dtc

Diameter of the crater

Dfr = 125 x Dtc

If Dfr lt Dsc the crater is a simple crater Dfr = 125 x Dtc (after Marcus Melosh and Collins 2004)

If Dfr =gt Dsc the crater is a complex crater Dfr = 117 x Dtc113

x Dsc-013

(from McKinnon and Schenk 1985)

Height of the edges of the crater - Hfr

Hfr = 07(Dtc4Dfr

3)

Thickness of breccias

For a simple crater For a complex crater

ltgt

with Vm (volume of breccia) and E energy of the impact (J)

N O T E S

Final depth of the crater (distance between the top of the edges of the crater [ridge line] and the top of the breccia lens that covers the bottom of the crater)

For a simple crater For a complex craterdfr = dtc + Hfr - tbr dfr = 5036 Dfr

03

NOTES

These formulas are derived from the recommendations ofEarth Impact Effects Program

Robert Marcus H Jay Melosh and Gareth Collins (Meteoritic amp Planetary Science)

Links

- httpwwwunbcapasscImpactDatabase lt database of terrestrial craters

- Google Earth amp Impact craters lt list of terrestrial craters

Project Name Client

Project No Prep By Date

Data of the object and the target

Mass of the object (kg) 10E+02

Mass (kg) 597E+24 Weigh in Newtons (ground level) 981088

Equatorial Radius (km) 6378137 Density of the object (kgm3) 5000

Polar Radius (km) 6356752 Diameter of the object (m) 10

calc g on surface level (mssup2) 981

Angle of impact (degree) 12000

Angle in radians (rad) 20944

Unknown

sedimential ground Speed at impact (ms) 20000 20000 kms

crystalline ground x 4750 Speed (kmh) 72000

[check one cell please]

Density of the target (kgm3) 3200

Kinetic Energy [joules] 2000E+10 2000E+04 mega-J Diameter of transition - Dsc (m) 4750 (lt default )

Kinetic Energy [calories] 4778E+09 4778E+03 mega-cal Diameter of the transient crater - Dtc (m) 31482

gt Depth of the transient crater (m) 11208

Kinetic energy [eqmass kgf] 2039E+09 2039E+06 tonnes-force Diameter of the crater - Dfr (m) 39352 (simple crater)

Kinetic energy [TNT tonne (s)] 4779E+00 4779E+03 kilo(s) TNT Height of the edges of the crater (m) 1128

Note by convention gt 1 kg of TNT = 106 calories = 4 185106J Height of the breccias of the crater (m) 3652

Final depth of the crater (m) 8684

Radius of the object (m) 1000

Volume (m3) 4189E+03

Density of the object (kgm3) 1000000

Mass (kg) 4189E+07

This is the distance between the top of the edges of the crater (ridge line)

Calculation of the mass of an object (spherical)

Results Estimate of the size of the crater

and the top of the breccia lens that covers the bottom of the crater

CALCULATION OF AN IMPACT ON EARTH

EARTH

Nature of the target ground (check a cell)

Two types of celestial objects can collide with our planet asteroids and comets

Asteroids are composed of rocks and metals and their density varies between 2000 and 8000 kgm3

For example Chondrite CM in density from 3400 to 3800 kgm3 (Mighei meteorite fallen on June 18 1889 in Ukraine)

Their speed at the entrance into the atmosphere is between 11 and 21 kms

Comets are primarily composed of ice Their density is between 500 and 1500 kgm3

and their speed between 30 and 72 kms

Other objects - not observed to date - can potentially collide with the Earth Its interstellar objects

their speed is greater than 72 kms (otherwise they would orbit around the Sun)

Because of their origin their nature and density are unknown

FORMULAS

Kinetic energy of the impact (Joules) Ec (J) = 12Mvsup2

with M mass of the car in kg and v is its velocity in ms Emitted energy by convention 1 kg of TNT = 106 calories = 4 185106J

Note 1 calorie (cal) = 41855 J The bomb dropped on Hiroshima in 1945 had a power

of approximately 15 kilotonnes (15 000 tonnes of TNT)

Dsc transitional transition diameter between simple craters and complex on Earth equal to

- when it does not know the nature of the target field gt 3200

- in a sedimentary field gt 2250

- in a crystalline field gt 4750

Diameter of a transient crater Dtc

Note all diameters depths thicknesses and heights

are expressed in m

r i density of the asteroid in kgm3 (and mj its mass in kg)

r c target density kgm3

fi diameter of the meteorite in m

ui speed of the meteorite at impact in ms

g acceleration due to gravity of the target (equal to 981 mss on average on Earth)

θ angle of impact the horizontal (for vertical impact θ = 90 deg)

Depth of the transient crater - dtc

Diameter of the crater

Dfr = 125 x Dtc

If Dfr lt Dsc the crater is a simple crater Dfr = 125 x Dtc (after Marcus Melosh and Collins 2004)

If Dfr =gt Dsc the crater is a complex crater Dfr = 117 x Dtc113

x Dsc-013

(from McKinnon and Schenk 1985)

Height of the edges of the crater - Hfr

Hfr = 07(Dtc4Dfr

3)

Thickness of breccias

For a simple crater For a complex crater

ltgt

with Vm (volume of breccia) and E energy of the impact (J)

N O T E S

Final depth of the crater (distance between the top of the edges of the crater [ridge line] and the top of the breccia lens that covers the bottom of the crater)

For a simple crater For a complex craterdfr = dtc + Hfr - tbr dfr = 5036 Dfr

03

NOTES

These formulas are derived from the recommendations ofEarth Impact Effects Program

Robert Marcus H Jay Melosh and Gareth Collins (Meteoritic amp Planetary Science)

Links

- httpwwwunbcapasscImpactDatabase lt database of terrestrial craters

- Google Earth amp Impact craters lt list of terrestrial craters

Two types of celestial objects can collide with our planet asteroids and comets

Asteroids are composed of rocks and metals and their density varies between 2000 and 8000 kgm3

For example Chondrite CM in density from 3400 to 3800 kgm3 (Mighei meteorite fallen on June 18 1889 in Ukraine)

Their speed at the entrance into the atmosphere is between 11 and 21 kms

Comets are primarily composed of ice Their density is between 500 and 1500 kgm3

and their speed between 30 and 72 kms

Other objects - not observed to date - can potentially collide with the Earth Its interstellar objects

their speed is greater than 72 kms (otherwise they would orbit around the Sun)

Because of their origin their nature and density are unknown

FORMULAS

Kinetic energy of the impact (Joules) Ec (J) = 12Mvsup2

with M mass of the car in kg and v is its velocity in ms Emitted energy by convention 1 kg of TNT = 106 calories = 4 185106J

Note 1 calorie (cal) = 41855 J The bomb dropped on Hiroshima in 1945 had a power

of approximately 15 kilotonnes (15 000 tonnes of TNT)

Dsc transitional transition diameter between simple craters and complex on Earth equal to

- when it does not know the nature of the target field gt 3200

- in a sedimentary field gt 2250

- in a crystalline field gt 4750

Diameter of a transient crater Dtc

Note all diameters depths thicknesses and heights

are expressed in m

r i density of the asteroid in kgm3 (and mj its mass in kg)

r c target density kgm3

fi diameter of the meteorite in m

ui speed of the meteorite at impact in ms

g acceleration due to gravity of the target (equal to 981 mss on average on Earth)

θ angle of impact the horizontal (for vertical impact θ = 90 deg)

Depth of the transient crater - dtc

Diameter of the crater

Dfr = 125 x Dtc

If Dfr lt Dsc the crater is a simple crater Dfr = 125 x Dtc (after Marcus Melosh and Collins 2004)

If Dfr =gt Dsc the crater is a complex crater Dfr = 117 x Dtc113

x Dsc-013

(from McKinnon and Schenk 1985)

Height of the edges of the crater - Hfr

Hfr = 07(Dtc4Dfr

3)

Thickness of breccias

For a simple crater For a complex crater

ltgt

with Vm (volume of breccia) and E energy of the impact (J)

N O T E S

Final depth of the crater (distance between the top of the edges of the crater [ridge line] and the top of the breccia lens that covers the bottom of the crater)

For a simple crater For a complex craterdfr = dtc + Hfr - tbr dfr = 5036 Dfr

03

NOTES

These formulas are derived from the recommendations ofEarth Impact Effects Program

Robert Marcus H Jay Melosh and Gareth Collins (Meteoritic amp Planetary Science)

Links

- httpwwwunbcapasscImpactDatabase lt database of terrestrial craters

- Google Earth amp Impact craters lt list of terrestrial craters

Final depth of the crater (distance between the top of the edges of the crater [ridge line] and the top of the breccia lens that covers the bottom of the crater)

For a simple crater For a complex craterdfr = dtc + Hfr - tbr dfr = 5036 Dfr

03

NOTES

These formulas are derived from the recommendations ofEarth Impact Effects Program

Robert Marcus H Jay Melosh and Gareth Collins (Meteoritic amp Planetary Science)

Links

- httpwwwunbcapasscImpactDatabase lt database of terrestrial craters

- Google Earth amp Impact craters lt list of terrestrial craters

Asteroids are composed of rocks and metals and their density varies between 2000 and 8000 kgm3

For example Chondrite CM in density from 3400 to 3800 kgm3 (Mighei meteorite fallen on June 18 1889 in Ukraine)

Other objects - not observed to date - can potentially collide with the Earth Its interstellar objects

Emitted energy by convention 1 kg of TNT = 106 calories = 4 185106J

The bomb dropped on Hiroshima in 1945 had a power

of approximately 15 kilotonnes (15 000 tonnes of TNT)

lt transition crater (Mars)

Note all diameters depths thicknesses and heights

are expressed in m

If Dfr lt Dsc the crater is a simple crater Dfr = 125 x Dtc (after Marcus Melosh and Collins 2004)

If Dfr =gt Dsc the crater is a complex crater Dfr = 117 x Dtc113

x Dsc-013

(from McKinnon and Schenk 1985)

Simple Crater

Complex Crater

with Vm (volume of breccia) and E energy of the impact (J)

N O T E S

Final depth of the crater (distance between the top of the edges of the crater [ridge line] and the top of the breccia lens that covers the bottom of the crater)

Final depth of the crater (distance between the top of the edges of the crater [ridge line] and the top of the breccia lens that covers the bottom of the crater)