# A meteor falls in a Mediterranean-like sea: what is the impact?

A meteor with a diameter of 300 meters crashes into the middle of a circular sea with a radius of 1500 km and with a speed of 30 km/s.

Civilizations (and humanity as a whole) that are situated around this sea have Bronze Age technology. How will the impact influence these civilizations? Will it be a total destruction of humanity, or perhaps result in one bad year?

And will the civilizations situated around this sea be completely destroyed, or partially destroyed?

Overall, what are the profound impacts of the event on the marine/terrestrial ecosystem and climate in the long and short term?

## 1 Answer

The impact will be barely noticeable on planetary scale. The tsunami will cause some damage, but nothing irreversible or long lasting on large scale.

A meteor impact calculator can answer your question on the effects of the impact

Your Inputs:

• Distance from Impact: 1500.00 km ( = 932.00 miles )
• Projectile diameter: 300.00 meters ( = 984.00 feet )
• Projectile Density: 8000 kg/m3
• Impact Velocity: 30.00 km per second ( = 18.60 miles per second )
• Impact Angle: 90 degrees
• Target Density: 1000 kg/m3
• Target Type: Liquid water of depth 1000.0 meters ( = 3280.0 feet ), over crystalline rock.

Atmospheric Entry:

• The projectile begins to breakup at an altitude of 23300 meters = 76400 ft
• The projectile reaches the ground in a broken condition. The mass of projectile strikes the surface at velocity 29.8 km/s = 18.5 miles/s
• The energy lost in the atmosphere is $$5.93 \times 10^{17}$$ Joules = $$1.42 \times 10^2$$ MegaTons.
• The impact energy is $$5.03 \times 10^{19}$$Joules = $$1.20 \times 10^4$$ MegaTons.
• 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 0.357 km by 0.357 km

Crater Dimensions:

• The crater opened in the water has a diameter of 13.1 km ( = 8.17 miles ).
• For the crater formed in the seafloor: Crater shape is normal in spite of atmospheric crushing; fragments are not significantly dispersed.
• Transient Crater Diameter: 6.31 km ( = 3.92 miles )
• Transient Crater Depth: 2.23 km ( = 1.39 miles )
• Final Crater Diameter: 8.07 km ( = 5.01 miles )
• Final Crater Depth: 555 meters ( = 1820 feet )
• The crater formed is a complex crater.
• The volume of the target melted or vaporized is 0.15 km3 = 0.0359 miles3
• Roughly half the melt remains in the crater, where its average thickness is 4.78 meters ( = 15.7 feet ).
• The crater opened in the water has a diameter of 13.1 km ( = 8.17 miles ).

Thermal Radiation:

• The fireball is below the horizon. There is no direct thermal radiation.

Seismic Effects:

• The major seismic shaking will arrive approximately 5 minutes after impact.
• Richter Scale Magnitude: 7.0
• Mercalli Scale Intensity at a distance of 1500 km: Nothing would be felt. However, seismic equipment may still detect the shaking.

Ejecta:

• The ejecta will arrive approximately 10.6 minutes after the impact.
• At your position there is a fine dusting of ejecta with occasional larger fragments
• Average Ejecta Thickness: 4.21 microns ( = 0.166 thousandths of an inch )
• Mean Fragment Diameter: 38.7 microns ( = 1.52 thousandths of an inch )

Air Blast:

• The air blast will arrive approximately 1.26 hours after impact.
• Peak Overpressure: 874 Pa = 0.00874 bars = 0.124 psi
• Max wind velocity: 2.05 m/s = 4.59 mph
• Sound Intensity: 59 dB (Loud as heavy traffic)
• Damage Description: Glass windows may shatter.

Tsunami Wave:

• The impact-generated tsunami wave arrives approximately 4.2 hours after impact.
• Tsunami wave amplitude is less than 8.1 meters ( = 26.5 feet).
• "The impact will be barely noticeable." except for the last effect.. a Tsunami of 8 meters over a coastal region of 11000 kilometers would be quite devastating ! May 22 at 9:12