After plugging in the parameters that Neal deGrasse Tyson mentioned (100m in diameter, impacting 500 miles away – in 3 miles of ocean), it yielded some pretty insignificant results (besides the tsunami that would be generated).
Distance from Impact: 805.00 km = 499.90 miles
Projectile Diameter: 100.00 m = 328.00 ft = 0.06 miles
Projectile Density: 3000 kg/m3
Impact Velocity: 17.00 km/s = 10.56 miles/s
Impact Angle: 45 degrees
Target Density: 1000 kg/m3
Target Type: Liquid Water of depth 4.57 meters, over typical rock.
Energy before atmospheric entry: 2.27 x 1017 Joules = 5.42 x 101 MegaTons TNT
The average interval between impacts of this size somewhere on Earth during the last 4 billion years is 2.4 x 103years
The projectile begins to breakup at an altitude of 54000 meters =
The projectile reaches the ground in a broken condition. The mass of projectile strikes the surface at velocity 6.66 km/s = 4.14 miles/s
The impact energy is 3.49 x 1016 Joules = 8.33 MegaTons.
The broken projectile fragments strike the ground in an ellipse of dimension 0.81 km by 0.573 km
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 Earth’s rotation period or the tilt of its axis.
The impact does not shift the Earth’s orbit noticeably.
The crater opened in the water has a diameter of 1.85 km = 1.15 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: 1.12 km = 0.695 miles
Transient Crater Depth: 0.396 km = 0.246 miles
Final Crater Diameter: 1.4 km = 0.869 miles
Final Crater Depth: 0.298 km = 0.185 miles
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 138 m = 454 ft.
At this impact velocity ( < 12 km/s), little shock melting of the target occurs.
At this impact velocity ( < 15 km/s), little vaporization occurs; no fireball is created, therefore, there is no thermal radiation damage.
The major seismic shaking will arrive at approximately 161 seconds.
Richter Scale Magnitude: 5.2
Mercalli Scale Intensity at a distance of 805 km:
- Nothing would be felt. However, seismic equipment may still detect the shaking.
Most ejecta is blocked by Earth’s atmosphere
The air blast will arrive at approximately 2440 seconds.
Peak Overpressure: 138 Pa = 0.00138 bars = 0.0195 psi
Max wind velocity: 0.324 m/s = 0.725 mph
Sound Intensity: 43 dB (Easily Heard)