Oswald took 10.2 seconds to fire all three shots.

[Brian Roselle]

The shock wave is due to the rapid compression of air by the bullet and spreads out from the nose of the bullet in a cone shape at the speed of sound as the bullet passes through the air.  The angle of the cone is called the Mach angle where the sine of the Mach angle is equal to the speed of sound divided by the bullet speed (or 1/mach no.):


In the case of the bullet fired by the M/C rifle (muzzle speed Mach 2 around 2200 feet/sec), the Mach Angle would be 30 degrees (sin(30)=1/M=1/2).  The energy in the wave is continuous as it is caused by the bullet plowing through air whereas the muzzle blast is a one-time release of energy caused by the compressed gas from the ignited gunpowder exploding out of the muzzle.

So, it appears to me that Wiegman and Kilduff and the Cabells were not within the cone and could not have heard the crack of the shock wave.  Only people west of the SN and relatively close to the bullet path could have heard it.

That looks like a very good description related to shock waves and expanding as a cone. I agree with your conclusion that those individuals around the intersection would not have encountered the shock waves.

What I think is interesting and implied by what you describe is that for any three shots (time wise) from the depository, Greer and Kellerman, even though they would have been basically right in line with the bullet trajectories, probably would not have heard shock waves either. If the bullets or fragments went subsonic just before reaching them, it seems those two would have been engulfed inside a truncated expanding shock cone, and as such never heard the shock wave. Just a consequence of the geometry.

[James Hackerott]

Many years ago I created a 3D stabilized version of the Z-film (need Red/Blue glasses for 3D effect) and I used the stabilized data to study the camera shake.

If Zapruder responded to any loud noises during shooting the Z film, then telltale jiggles would show up as involuntary camera shake. If you take any stock in involuntary "jiggling" in response to loud sounds (which is definitely a thing), this chart might interest you.

http://www.kohlbstudio.com/Images/Zshake_yd-d.png

A reflexive response to a loud noise is an up and down motion (y axis). I filtered out the X and focused on the Y because this jiggle motion is significant versus "panning", which is not associated with a gunshot jiggle. All the other jiggle analyses seemed to ignore this aspect.

Look at the "signature" reflexive response to z313. That is your control.

There appear to be a few possible candidate spikes that might have been the 1st shot. However, there were a lot of frames spliced out of the beginning of the Z-film and Zapruder can't recall ever taking his finger off the trigger. The 1st shot might be in that footage, which got spliced out. BTW, where is the original film? Zapruder only got a copy back.

Note that there's a telltale jiggle that peaks at z230, which suggests that Zapruder was responding to a sound at z225. The sound appeared to reach Zapruder 1/6th of a second after the bullet struck JFK at z222, behind the Stemmons sign.

Note the splices at z158 & z213.

Note the massive edit at z333 just when we would expect to see a hole in the back of JFK's head.

Love it! Viewed with my Red/Cyan clip-on.

[Andrew Mason]

That looks like a very good description related to shock waves and expanding as a cone. I agree with your conclusion that those individuals around the intersection would not have encountered the shock waves.

What I think is interesting and implied by what you describe is that for any three shots (time wise) from the depository, Greer and Kellerman, even though they would have been basically right in line with the bullet trajectories, probably would not have heard shock waves either. If the bullets or fragments went subsonic just before reaching them, it seems those two would have been engulfed inside a truncated expanding shock cone, and as such never heard the shock wave. Just a consequence of the geometry.

I agree.  The supersonic compression of air stops being generated when the bullet stops.  If a person is ahead of the bullet when it stops and ahead of a line from the bullet in the direction of the shock wave trajectory, that person cannot sense the shock wave:

[Royell Storing]

 So how does Kilduff while sitting inside a Hard Top/Closed Car feel a "muzzle blast" that originates from the 6th Floor? He doesn't. Now, if a gun was fired from inside that same car, you gotta story.

[Marjan Rynkiewicz]

That looks like a very good description related to shock waves and expanding as a cone. I agree with your conclusion that those individuals around the intersection would not have encountered the shock waves.

What I think is interesting and implied by what you describe is that for any three shots (time wise) from the depository, Greer and Kellerman, even though they would have been basically right in line with the bullet trajectories, probably would not have heard shock waves either. If the bullets or fragments went subsonic just before reaching them, it seems those two would have been engulfed inside a truncated expanding shock cone, and as such never heard the shock wave. Just a consequence of the geometry.

Brian u are usually good at logic/science, apart from your decision to engage with some of the morons on this forum.
But your comment means that u/me/we/us cant hear an/any/all explosions.

In other words, there is no such thing as a shock wave.
What we have is sound. And if the leading edge of the sound is powerfull then we might call it a shock wave.
So, at what distance duzz a shockwave stop being a shockwave.
Answer, there is no answer, koz there is no such thing as a shockwave, its just sound.
Trump got a bloody ear from a shockwave, a  nearmiss, lucky.

[Brian Roselle]

Brian u are usually good at logic/science, apart from your decision to engage with some of the morons on this forum.
But your comment means that u/me/we/us cant hear an/any/all explosions.

In other words, there is no such thing as a shock wave.
What we have is sound. And if the leading edge of the sound is powerfull then we might call it a shock wave.
So, at what distance duzz a shockwave stop being a shockwave.
Answer, there is no answer, koz there is no such thing as a shockwave, its just sound.
Trump got a bloody ear from a shockwave, a  nearmiss, lucky.

I don’t know if I can answer your question but I will take a stab.

I think you can consider the shock wave a wave front, and made from sound waves. It is different than the spherical expanding muzzle blast wave front and is more linear as being a continual summation of sounds as the bullet travels. Imagine the bullet continually giving off spherically expanding sounds that are continuously added up to make the shock wave front.

I guess practically speaking the shock wave is no longer a wave when it fully dissipates, and too weak to detect or hear.

My guess on how it dissipates is only a guess, as I have not seen a definitive explanation. Basically, I would guess the wavefront dissipates as 1/R distance from the trajectory that formed it. Again, this just a guess, but looking at an individual sound point source, like the muzzle blast, those dissipate as 1/R^2. This is based on surface area of its expanding sphere (4*Pi*R^2). The shock wave, as effectively a composite of point source sounds, would be related to adding up point sources. So constantly adding them up is like integrating them. The integral of the 1/R^2 function becomes a form like 1/R. This would be my guess as to the dissipation rate of the shock wave, as 1/R where R the distance from the bullet trajectory forming it.
Again, this is some speculation, so you should look it up to confirm what the answer may be.

 P.S. I think they are derived from sounds and are real. Charles mentioned being able to feel normal expanding loud sounds, like muzzle blasts and rocket engines. In the case of a shock wave, if the shock wave is strong enough, it also can be felt. When I was a kid in the early 60’s and lived not far from Offout Airforce base and SAC headquarters around the fall 1962, there were a lot of big jets flying around and for some reason many sonic booms. I definitely felt those shock waves.

[Charles Collins]

Thunder is a sonic boom. A sonic boom is a shock wave created when an object moves faster than the speed of sound. Thunder is a sonic boom caused by lightning, which heats the air around it to extremely high temperatures.

Explanation
Lightning
Lightning can reach temperatures of 54,000°F, which is five times hotter than the surface of the sun.
Air expansion
The sudden increase in temperature causes the air to expand rapidly, creating a shock wave.
Shock wave
The shock wave travels along the lightning bolt, creating millions of sonic booms.
Sound
The sound of thunder is a combination of these sonic booms, which we hear as a rumble or a loud bang.
Distance
Thunder from a nearby lightning strike sounds like a sharp crack or loud bang, while thunder from a distant strike sounds like a continuous rumble.
Sonic booms can also be created by aircraft that travel faster than the speed of sound. This is known as "breaking the sound barrier".

[Brian Roselle]

Thunder is a sonic boom. A sonic boom is a shock wave created when an object moves faster than the speed of sound. Thunder is a sonic boom caused by lightning, which heats the air around it to extremely high temperatures.

Explanation
Lightning
Lightning can reach temperatures of 54,000°F, which is five times hotter than the surface of the sun.
Air expansion
The sudden increase in temperature causes the air to expand rapidly, creating a shock wave.
Shock wave
The shock wave travels along the lightning bolt, creating millions of sonic booms.
Sound
The sound of thunder is a combination of these sonic booms, which we hear as a rumble or a loud bang.
Distance
Thunder from a nearby lightning strike sounds like a sharp crack or loud bang, while thunder from a distant strike sounds like a continuous rumble.
Sonic booms can also be created by aircraft that travel faster than the speed of sound. This is known as "breaking the sound barrier".

Good reference and it reminds me of another thing I also didn't mention in my reply is the shock wave that atomic explosions generate. Although its commonly called a shock wave, I think it is different because of its spherical expansion characteristics. It appears it can be called an incident blast wave that is also called a shock wave that occurs when a point explosive detonates, releasing energy and compressing the surrounding air. The blast wave expands outward from the explosion in a spherical shape. I think this is what was seen on some of those old nuclear explosion films.

The nomenclature I was focusing on was for bullet shock waves, different from those nuclear explosion shock waves.