Credible nuclear deterrence effects, debunking dogmatic "disarm or be annihilated" enemy propaganda. Realistic effects and credible nuclear weapon capabilities for deterring or stopping aggressive invasions and attacks which could escalate into major conventional or nuclear wars.

Sunday, May 07, 2006

Broken windows in Las Vegas by Nevada nuclear weapon tests





Above: Nevada nuclear tests in 1951 were photographed from the desert casino town Las Vegas, some 75 miles to the south-east of ground zero. Refraction of shock waves by the atmosphere occasionally cracked large store windows in Las Vegas, but this was purely a shock diffraction effect and of course there was no wind pressure at that distance to accelerate glass fragments into a penetrating threat. For a 1 megaton surface burst over unobstructed terrain, the range of glass fragment hazard due to blast wind acceleration is 7 miles; this should be compared to a radius of 25 miles for cracked windows! (Anti-civil defense propaganda deliberately confuses the very low blast pressures required for cracked windows with the much higher pressures that are accompanied with sufficiently strong winds to cause a flying glass fragment hazard.)


Some declassified nuclear test blast reports by Jack W. Reed, who has a site at http://www.nmia.com/~jwreed/, are now available to all online from http://stinet.dtic.mil/.

Climatology of Airblast Propagations from Nevada Test Site Nuclear Airbursts, ADA383346. SANDIA CORP ALBUQUERQUE NM. Reed, Jack W. Report Date: December 01, 1969. 122 Pages

Blast Predictions at Christmas Island, ADA349666. SANDIA NATIONAL LABS ALBUQUERQUE NM. Reed, Jack W., and Church, Hugh W. Report Date: October 25, 1963. 46 Pages

Long-Distance Blast predictions, Microbarametric Measurements, and Upper-Atmosphere Meteorological Observations for Operations Upshot-Knothole, Castle, and Teapot, AD0342207 . SANDIA CORP ALBUQUERQUE NM. Cox, E. F., and Reed, J. W. Report Date: September 20, 1957. 93 Pages.

I've given some of my calculations on close-in fireball shock waves and high pressure air blast already here and here, but Jack Reed was concerned with the harder predictions for the more distant blast broken windows by atmospheric refraction in Nevada and Pacific nuclear tests. Considering that Las Vegas was only 75 miles from the Nevada test area, that was a bigger concern than fallout prediction (which I've commented on already here). Jack Reed says at http://www.nmia.com/~jwreed/expl1.htm:

'One of the first (actually the fourth) atmospheric nuclear tests (Operation RANGER, February 1951) broke large store windows on Fremont Street in downtown Las Vegas, Nevada, over 60 miles away. A similar 8-kt (kilotons) device had been fired the week before, and a smaller, 1-kt device the day before, without being heard. Los Alamos scientists guessed that it must have been caused by a change in weather, and they were correct. A library citation search turned up a report by Dr. Everett F. Cox, who had directed long-range acoustic monitoring of the massive explosive destruction of collected Axis munitions following WW-II at Helgoland, that showed a strong weather influence. By 1951, Cox was found doing his physics at Sandia (now National Laboratories), Alburquerque, New Mexico, (a branch of Los Alamos Scientific Laboratory until 1949), where I was a meteorologist in their Field Test Department.

'I was concerned with bomb ballistics and optical refraction problems in photo-tracking bomb trajectories through desert mirages at Sandia's Salton Sea Test Base, CA. I had started at Sandia in 1948. Even as a recalled Air National Guardsman (1951-53) during the Korean War, I was kept (with my Q-clearance) at Kirtland AFB Weather Station and Sandia Lab in a "military liaison" capacity.

'We began that summer (1951) with explosions of Navy war-surplus anti-submarine depth charges, monitored at long ranges, to 200 km (125 miles), by pressure sensors borrowed from the Navy. We applied atmospheric acoustic raypath calculations, provided by Lord Rayleigh, Fujiwara, and Rothwell, and using radiosonde (raob) weather balloon reports, to try to explain results and build a prediction system.

'And this system worked quite well, as demonstrated on November 1, 1951, by 21-kt Shot Dog, when weather threatened to focus airblast by jet stream winds blowing toward Las Vegas. But the AEC Test Manager had another problem. Over 3,000 press and Civil Defense observers had been brought out to watch atomic tests. They had been there almost two weeks, had spent their travel money (or lost it in Vegas Strip casinos), and had then moved to the free Desert Rock (Army) tent city, just outside the AEC Camp Mercury, where meals were only $1.00.

'This food supply was about to run out; under this pressure, the the Test Manager decided to shoot. Again, windows were smashed along Fremont Street; Sears' large show-windows fell out on the sidewalk. In those days, however, this was in a commercial section, with no pedestrians so early in the morning. After that, blast predictions were taken very seriously, and only one more broken window was reported (but no claim made) in Las Vegas from any further nuclear airblasts through 1968.

'That one incident came during Operation TEAPOT, from 20-kt Shot Bee, 3/22/55, by an MB-recorded 200 Pa (pascals) overpressure, 290.4 Pa amplitude airblast wave. This observation, plus two other reports, of single windows broken, in St. George, Utah, 200 km east of NTS, during TEAPOT from similar recorded pressures, provided a basis for an estimated threshold for airblast window damage. This 200 Pa (2 mb - millibar, 0.03 psi) overpressure threshold still appeared valid in 1988, when only one damage claim out of more than 17,000, came from a lower estimated overpressure (160 Pa) from the large PEPCON accidental explosion in Henderson, Nevada. ... Near the end of HARDTACK I, rocket-delivered megaton-class Shots Teak and Orange were fired over Johnston Island, giving a host of observations that took years to explain.'

Left: large window shattered outward in Fremont Street, Las Vegas, Nevada; Sears' large show-windows fell out on the sidewalk, due to the 21 kt Dog test at the Nevada test site. This was due to the suction phase of the blast which had been focussed on Las Vegas by jet stream winds. The man responsible for predicting this damage, Jack Reed, blamed the test manager for firing the nuclear bomb under adverse conditions because the food had run out for 3,000 press and civil defense observers (see quotation from Reed's site, above). A big window is more likely to fail than a small one. 0.03 psi is small compared to normal pressure (14.7 psi), but the force exerted on a big window is appreciable, for example a window 6 feet high and 10 feet wide subject to 0.03 psi gets 6 x 10 x 144 x 0.03 = 259.2 pounds of force (1153 Newtons). At great distances, the window often survives the inward push in the compression phase but then shatters when the low-pressure (rarefaction) phase occurs, pulling the window the other way suddenly. There is no significant flying glass hazard (except from vertically falling glass right beside the window), because the blast winds are too weak to accelerate fragments into high velocity missiles. Near the explosion there is a greater risk of this, but clothing or 'duck and cover' action offers good protection (see Glass Fragment Hazard from Windows Broken by Airblast, ADA105824; Operation PLUMBBOB: Secondary Missiles Generated by Nuclear-Produced Blast Waves, ADA397401; ADA383465; ADA394861; Operation TEAPOT: Distribution and Density of Missiles from Nuclear Explosions, ADA395151 - the 'open shot' with the community of different types of American houses built about a mile from ground zero in Nevada, for which the data is given in this last report is of course Apple-2.).

'Shock waves go out in all directions from the detonation. Some strike the earth and are dissipated. Some bounce back to earth from various atmospheric layers. If they reach earth at an inhabited point they may be felt or heard.

'Waves curved back to earth by the ionosphere, which is an atmospheric layer over 50 miles above the earth, have been recorded on very sensitive instruments 100 or more miles from the target area. There is no evidence that they have been heard at that distance or have caused any damage.

'The ozonosphere, a layer 20 to 35 miles above the earth, bends waves back at distances from 60 to 150 miles. Usual ozonosphere wind directions cause these waves to reach St. George and Cedar City, Utah, in winter and Bishop, Calif., in summer. Every shot fired in Nevada has been heard either in St. George or Bishop, or both.

'Past Experience With Blast

'Light damage to structures and broken windows have resulted up to 100 miles, most of this having been in the first series on a line from the test site through Las Vegas and Henderson. Only very light damage has been reported within 100 to 200 miles. Blast has been heard but has not caused damage at greater distances, including Los Angeles, Calif., and Albuquerque, N. Mex.' - ATOMIC TEST EFFECTS IN THE NEVADA TEST SITE REGION, UNITED STATES ATOMIC ENERGY COMMISSION, JANUARY 1955.


Further vital reports on low overpressure air blast focussing by refraction etc can be found online here (Jack Reed's report ADA279735 on the DANNY BOY cratering nuclear test) and a report by John Slater here.

There is also an interesting discussion of air blast and ground shock problems with the efforts in the 1960s to excavate a new Panama canal using relative clean (REDWING-NAVAJO, 5% fission test, type) nuclear explosives in a book: Emperors in the jungle By John Lindsay-Poland.

1 Comments:

At 4:21 pm, Blogger nige said...

From: Jack Reed
To: Nigel B. Cook
Sent: Monday, June 26, 2006 6:08 PM
Subject: Blogs and memories


Hi Nigel, I was amazed last night when I got around to visiting your blog site. Obviously, you're no beginner at studying nuclear weapons and technology. Much of the stuff there I was not particularly familiar with, but several items brought back old memories and faces. Thanks. Is your intent to put together a book?

Your collection of info on the Japanese and Rongelap radiation survivors was interesting to me, having had some accidental exposures totalling around 64 R, with only 4 R on an official film badge. A few years ago United States support for the Japanese survivor studies was cut off, to my chagrin. Later I inferred the reason. One of their reports claimed that of 47,000 being tracked after 40-100 R exposures, they were now dying - at one-quarter the rate of their unexposed controls. My conclusion: politically unacceptable to the American anti-nukes. Now, later figures show 3/4 of my veteran colleagues of WW-II are dead, so we (40-100 R) have been "vaccinated". Neat!

The other stong recollection was about that Teak cloud. Some twenty minutes after the shot, I spotted a white "smoke ring" in the NW sky, from the deck of the carrier USS Boxer. Back to my home office, I did the calculation of the closest point where it could be in the sun (01:00 Johnston Island time). I haven't easy access to my old files and forget the exact numbers, but that required a SE wind of around 1500 knots. My colleague, Hugh Church, then did the calculations for the hydrostatic winds around the hot, low pressure area under the direct sun, and came up with nearly the same wind direction and speed. We submitted these two reports to the J. Geophysical Research, and received prompt rejection because "everyone knew that the circulation at those ionospheric altitudes was dictated by the electric field." Some twenty years later, your Sir James Lighthill published a report based on neutral particle flow at such altitudes, because only a tiny fraction of the air was ionized and of no consequence. Hugh and I never got around to re-submitting our articles, but I did get to meet Lighthill at an Oxford meeting in 1985, and told him that chuckler. And finally, in 2003, I got to face a 93-year-old James Peoples, later-long-time-editor of Science Magazine and previously editor of the JGR. His response was "I am a chemist, and I had to rely on my advisors for such problems". More chuckles.

Straight Ahead, Jack W. Reed
And reed that boweth down to euery blaste. Chaucer, 1385

I believe in getting into hot water. I think it keeps you clean. G.K.Chesterton


----- Original Message -----
From: Nigel B. Cook
To: Jack Reed
Sent: Sunday, June 25, 2006 3:29 AM
Subject: Blast yield estimates controversy QQQQ


Hi Jack,

Many thanks for these comments on using the EMP to give the time of detonation in 1955 Teapot tests. I've been reading the sanitized report ITR-1660-(SAN), "Operation Hardtack: Preliminary Report, Technical Summary of Military Effects Programs 1-9", DASA, Sandia Base, Albuquerque, New Mexico, 23 September 1959, sanitized version 23 February 1999.

It contains a lot of blast data including a plot of all the Pacific data for very low overpressure blast, in Fig 6.13 on page 287, and also seems to refer to a report of yours concerning thermal radiation effects on page 453:

J. W. Reed and others, "Thermal Radiation from Low-Yield Bursts", Project 8.8, Operation Hardtack, ITR-1675, January 1959, Air Force Cambridge Research Centre, Laurence G. Hanscom Field, Bedford, Massachusetts, Secret Restricted Data.

One issue with thermal radiation is that some reports say it varies with yield. Did you find any evidence of this? Glasstone 1962/64 suggests that the thermal yield fraction for a surface burst varies from 1/7 or 14% for Nevada tests to 1/4 or 25% for Pacific tests. Brode's 1968 RAND Corp report on computer simulations indicates that the thermal yield fraction theoretically increases with bomb yield.

The fireball radius at second thermal brightness, when most radiation is emitted, scales up more rapidly (radius proportional to W^0.4) with yield than the blast pressure that greates nitrogen dioxide that shields some of the thermal radiation (radius proportional to W^1/3). Therefore, you would expect nitrogen dioxide in the shock wave to filter out more of the thermal radiation in a low yield burst than a high yield burst. This accounts for the rise in predicted thermal yield with yield in air bursts.

In a surface burst, the cratering action does much the same thing, throwing up a dirt over a radius that scales as the cube-root of yield, so it should have a greater shielding effect on the fireball radiation at maximum brightness at low yields than high ones. So the thermal fraction again should increase with increasing yield.

It is very hard to see how energy is really used in a nuclear explosion. Glasstone 1950 claimed that only about 1% is used in cratering and ground shock, but that was based on a theory that air blast caused both effects. Brode's 1960 RAND computer simulation showed the figure was 15% because the case shock of the bomb is denser than the air shock and couples far better to the ground. C. E. Adams of USNRDL in a 1958 report calculated that 3% of the energy in the Redwing-Inca tower shot was used for melting the observed mass of fallout. Report DNA 5159F-1 (1979) on simulations of mushroom cloud rise (for the main U.S. Department of Defense DELFIC fallout computer) states on page 12:

"On the basis of considerable experience with the cloud rise model we take the fraction of explosion energy used to heat air, soil and water to their initial temperatures to be 45% of the joule equivalent of the total yield, W."

This is a massive amount of energy, essentially the entire blast yield. Hence about 15% of the energy of the surface burst nuclear explosion is used in ground shock and cratering, 45% in mushroom cloud rise, and over 3% in melting fallout. This accounts for 63% of the explosion energy without mentioning nuclear radiation, blast or thermal!

But if you look at chapter 1 of Glasstone and Dolan, it says 50% is blast, 35% is thermal, 15% nuclear.

So there is really a total lack of accounting for the energy, and I think Glasstone and Dolan is severely misleading. The blast wave at high overpressures is losing energy very rapidly by heating up the air it engulfs. Therefore, it is a complete fiction to quote 50% blast yield. They get it by subtracting the thermal and nuclear yield from 100%, but clearly the blast wave is continuously leaving warm air behind and thus losing wave energy.

My calculations at http://glasstone.blogspot.com/2006/03/physical-understanding-of-blast-wave.html indicate that the blast wave begins with all the available fireball energy, 85% of the explosion energy, and then loses energy as the overpressure falls until it has only about 1.09% of the explosion energy when it has become basically a sonic wave at great distances. Therefore, the idea that the blast contains 50% of the energy is entirely misleading. It starts with 85% or so, and then loses energy by thermal radiation from the surface and from leaving behind hot air which rises to form the cloud, etc., until the energy is dow to 1.09% of the total.

On page 347 of ITR-1660-(SAN), the first American measurement of high altitude EMP was at the 2 kt Yucca test in 1958. The Teak shot EMP measurements failed because the shot went off directly overhead instead of 20 miles downrange due to a missile guidance error. They only measured the beta ionisation which affects radio/radar transmissions for hours, but it is the brief high frequency EMP which causes physical damage to equipment: "Shot Yucca ... [EMP] field strength at Kusaie indicated that deflection at Wotho would have been some five times the scope limits... The wave form was radically different from that expected. The initial pulse was positive, instead of the usual negative. The signal consisted mostly of high frequencies of the order of 4 Mc, instead of the primary lower-frequency component normally received ..."

Best wishes,
Nigel


----- Original Message -----
From: Jack Reed
To: Nigel Cook
Sent: Sunday, June 25, 2006 4:51 AM
Subject: Re: Electrical effects at the Nevada Control Point? QQQQ



Hi Nigel,

>I cannot understand how the EMP effect was kept secret until 1961.<
I didn't ever realize that it was, particularly after the high altitude Teak shot in 1958 disrupted communications over most of the Pacific. I was somewhat familiar with it and used the pulse in 1955 to give our distant (200 km) microbarograph operators a shot time on their paper recordings. We simply hung a hundred meters or so of copper wire to catch it, for the vast Nevada areas didn't have very reliable telephone contacts and we hadn't gotten an off-site radio system yet. Before that, in 1953 when I read in Scientific American about ham operators getting radio whistlers from lightning, I suggested in a report (that was classified at the time) that USSR nuclear tests could be easily detected at the southern conjugate in the Indian Ocean. I never got a response from the report, but 3-4 years later a navy man told me they were doing such monitoring with a pair of ships on site rotation from Western Australia. Again, I should have applied for a patent. That leads to another story.

Also, ca 1953-4, a Scientific American article described extremely bright flashes in laboratory shock tubes filled with argon. As a long-time member of the 188th Fighter Squadron, New Mexico Air National Guard, I published another classified report, "An Aircraft Psychological Defense Device", proposing flare-sized clear plastic shock tubes filled with argon to pop out when an enemy fighter got on your tail. The flash should stun him long enough to make an escape maneuver. The Air Force had different ideas, however, as such dog-fights became obsolete, and used argon shock devices to light up Viet Nam in night-time surveillance.

Anyway, I wasn't involved in general instrument maintenance in the immediate test areas and didn't pay much attention to their problems nor read all the various reports that came out. My concern was weather dependences - distant airblast and fallout - and I never was much interested in electricity.

Straight Ahead, Jack W. Reed
And reed that boweth down to euery blaste. Chaucer, 1385

I believe in getting into hot water. I think it keeps you clean. G.K.Chesterton


----- Original Message -----
From: Nigel Cook
To: Jack Reed
Sent: Wednesday, June 21, 2006 4:04 AM
Subject: Electrical effects at the Nevada Control Point? QQQQ


Hi Jack,

Thank you very much for setting the facts straight on the sound being associated with the first peak, taking a few milliseconds. All of the film tracks of blast waves sound more like hurricane winds, than bangs.

Since you were at the control point if - assuming it is not secret - you recollect EMP effects. I cannot understand how the EMP effect was kept secret until 1961. ...

 

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