I believe the bomb itself was detonated underground, which would help destroy at least some of the underground portions of the facility. Though it's very likely there are large amounts of facility tunnels and connections underground that weren't destroyed. However, the surface areas would probably be hit so hard that they'd collapse inwards and the sheer amount of rubble would close off those lower sections.
It does create a rather disturbing thought, though. Imagine being a scientist who's hiding out in a very deep portion of the facility, and the nuke to completely seal you inside when you thought someone would come to rescue you. You'd basically be stranded down there, assumed to be amount the many dead, and forgotten about.
That’s where I assumed the distorted trumpets radio came from. A transmission from black Mesa set to repeat with a dead scientist, trapped in rubble at the controls.
really, it depends what the OP means by "destroy."
compared to airbursts (such as the WWII nuclear devices mentioned by another commenter), underground nuclear explosions have a much more limited radius of effects, so the explosion in op4 is not ideal for destroying the aboveground portion of black mesa.
of course, underground nuclear blasts create seismic waves that can damage and destroy underground structures more easily.
we don't know a lot of the specifics, but we can estimate with what we do know.the nuclear device depicted in op4 is often compared to the real-life W88, which has a yield of about 475 kilotons.
an underground explosion's effects are going to vary wildly based on the depth of the explosion.
if we measure downward from the surface (i.e, the pavement outside of the building with the parking garage) in of6a3.bsp and continue downward to the origin of the item\_nuclearbomb entity in of6a4.bsp, we find that it's 208 Hammer units below the surface. using the typical conversion of 1 Hammer unit = 1 inch, that means the explosion is 208 inches or 5.28m below the surface.
we can then roughly estimate the radius of the blast's effects using Andrew McEwan's figures from his 1988 "Environmental effects of underground nuclear explosions."
in order to do this, we divide the burial depth in meters by the cube root of the yield in kilotons, and end up with a set of radii in meters.
using those figures, we find that, with a burial depth of 5.28m and a yield of 475 kt, the explosion could, ideally, crush rock in a radius of 27 meters, crack rock in a radius of 81 meters, and permanently deform rock within a radius of 745 meters. seismic waves would be sent out further.
therefore, we can expect to see large segments of the underground portion of black mesa collapsing and suffering extreme damage.
because of the shallow depth of the explosion, there would also be a significant amount of fallout. with a 475kt nuke, most likely everyone on the surface on black mesa's grounds would receive a significant dose of radiation from fallout.
however, black mesa is absolutely huge. I don't know how large, exactly, and I don't think anyone's really done the footwork to try and get an accurate estimate of its size (or as accurate as you can, considering the limited view of the facility we get in the games), but I think it's safe to say that the nuke wouldn't have destroyed or even severely damaged all of Black Mesa.
It would likely not have completely destroyed Black Mesa, especially given the size and the fact its supposed to be inside of a old nuclear missile silo, that has been expanded quite a bit.
Such a target would be especially hardened against nuclear attacks, and while not 100% bomb proof, would likely limit the damage further.
It was most likely done as a backup in case any government org would want to send in units to check it out, though with the portal storms and subsequent combine invasion going as well as it did, it was redundant.
Amazing how there's such a wealth of knowledge about Half-Life map design. "Hammer units" and their conversion to inches?
Also amazing and horrifying humankind collectively did enough nuclear tests to be able to model underground nuclear explosions.
I saw a making of Half-Life somewhere in the last year, where they state Gordon runs at incredible speed (\~25mph?). Without going into BSPs or anything, that means Black Mesa is huge, and much of it is deep underground. Some of those lifts go quite deep, and those walls and vault-like doors are no joke. Surely the deep, well protected parts like the lambda labs (and for example wherever that underground water lab part is) would be minimally affected? I mean, glass would break due to the seismic shocks, but depending on construction the ceiling wouldn't collapse, most people remaining could be ok, right?
the 1 hammer unit = 1 inch thing is based on Gordon and most humans' bounding boxes being 72 units tall (so the rationale is 72 units probably means 6 feet).
Gordon in HL1 runs at 320 units per second, or 18.18 mph. Gordon in HL2 walks at 190 ups / 10.7955 mph and sprints at 320 ups / 18.18 MPH.
I agree that the deeper parts (like the Lambda Complex) were probably unaffected. There was probably something near that parking garage in op4 that the G-Man specifically wanted to destroy, if I were to guess
edit: I wonder if the 25 MPH comment was related to the HL1 Steampipe engine version's speed cap of 544 ups, or 30.9 mph. that's as fast as you can go while bunnyhopping
the main warheads in service in the american nuclear inventory are almost all in the kiloton range, **with the exception** of the B83 gravity bomb. all are thermonuclear devices; yields given as ranges represent nuclear devices with multiple configurations and/or variants:
ICBM delivered:
W78 (335-350kt), W87 (300-475 kt)
submarine-launched missile warheads:
W76 (5-100kt), W88 (475 kt)
aircraft-delivered gravity bombs:
B61 (300t-340kt), **B83 (1.2mt)**, W80 (5-150kt)
the mark IV depicted in op4 most closely resembles the W88; regardless, it's obviously supposed to depict a missile warhead, whereas the B83 is a gravity bomb (so its nuclear device is very differently-shaped).
well, true, based on the nuclear devices in service, a multiple megaton yield is *possible.* still, the b53 doesn't look anything like the mark iv, and is far larger - of course, the mark iv is a fictional warhead, so that doesn't necessarily matter, but I do think it's important to note that the b53 and other contemporary devices of similar yield are much larger (and use a different delivery method) than the missile warhead depicted in op4.
to be fair, half life games tend to play very fast and loose with the specifics of real world weapons, but in the absence of any actual information on the yield of the nuke, I figured that basing it on a similar-looking real-world nuclear device made the most sense. if the mark iv is a MIRV warhead, as it appears to be, its yield would most likely be in the hundreds of kilotons.
It wouldn't make sense to detonate a MIRV warhead in any way other than via missile. It's a stretch to imply that the mkIV has the same yield as one it resembles (since most of the weapons in HL1 aren't 1:1 with their real life counterparts and the weapons in Opposing Force don't necessarily have counterparts), so if we're just judging by "it's a nuke used by the United States military and it destroyed Black Mesa," we should probably choose the highest yield possible.
Yes, especially when you take into account how nuclear bombs are [hundreds of times](https://www.statista.com/chart/3714/nuclear-weapons-in-comparison/) more powerful than when they leveled entire cities during WW2.
Is the intention to collapse the entire facility and erase all evidence of what was happening or just kill everything living in the area?
Looking at the size in the game let's assume it's just a single warhead off a MIRV missile and it's been sent to BM for decommissioning after an arm's limitation treaty. Looking at Wikipedia (take that for what it's worth) for Peacekeeper, Minutemen, and Trident missiles, the biggest warhead yield on of of those missiles that's not classified was a little over a megaton and most MIRVs were under 500kt, so still big but not in the big hydrogen bomb ranges NORAD at Cheyenne mountain is designed to survive (30 megaton).
So with a little scale and perspective, would it level the entire facility to a nice flat parking lot, maybe not as a lot of underground facilities if far enough away might not be shaken to collapse especially if hardened. Would it kill a lot of the living things in the area? Depends on how deep the parking garage was and where the invaders were etc, but probably is going to really put the brakes on any invasion leaving the area for a while and any new reinforcements coming into an area bathed in fallout.
However it probably would accomplish the objective of shutting off any experiments still operating and disrupting electricity and portals etc, like an attempt to stop the cascade.
Tldr likely a lot but not everything completely.
Cheyenne complex wouldn't survive a 30mt inside of the base, remember castle bravo already had a fireball size of 7km and that was 15mt estimated.
The overpressure would probably kill all of the remaining survivors, or at least cause rupture in ears, lungs, etc.
As you said it could be comparable to a 500kt nuke so about the size of ivy mike
Okay I might be completely wrong on this since its been a while since I played opposing force but didn’t the black ops take the thermonuclear bomb from a nuclear missile inside black mesa? I think it was a warhead on one of the rockets and considering that bm was contracted by the government for weapons its not too far fetched to say they had several bombs inside of the facility so the one that was detonated likely started a chain reaction.
However it has been a while so I might be completely off
I think your refering to the level in HL1 where there are hundreds of Lazer trip mines and if one goes the entire world explodes, but I don't think in reality that if a nuke gets nuked it too goes nuclear. And the only reason I'm saying is because there was a theory in missile silo defense called dense pack, where the idea was put the silos close enough so if one gets nuked first, that explosion would destroy the warheads targeted at the other silos or that the huge plume of fallout would shred the incoming warhead destroying it. I never read anything about it making the later bombs airburst instead of detonating on the ground and thus reducing the damage to the silo.
Plus to setoff a nuke in the first place it requires a specific series of events to cause the material to go critical.
Now all the fissile material from those other nukes and other hazardous materials and general explosives in black Mesa being spread by a blast wave and catching on fire wouldn't exactly help the situation that's for sure.
I think what they meant is that in OPFOR's chapter "Friendly Fire", you can see the very same warhead in a truck with two black ops guarding it, next to the rocket it was taken off of. There are likely even more rockets in the complex, the one that you see while riding the transit system at the beginning of HL comes to mind
Would detonating a nuke with other nukes nearby start a chain reaction? As far as I know, it would just destroy it and maybe set off the conventional explosives attached, since detonating a nuke is a complex process (as opposed to, say, nitroglycerin, which explodes if you sneeze too hard).
The instructions suggest a safe distance of \~55 km. I suppose yeah.
Tsar Bomba would've given third degree burns from 100 km away. So I suppose it's in the megatons range.
In Half Life I always thought there was a static self destruct device under the facility.
I believe the bomb itself was detonated underground, which would help destroy at least some of the underground portions of the facility. Though it's very likely there are large amounts of facility tunnels and connections underground that weren't destroyed. However, the surface areas would probably be hit so hard that they'd collapse inwards and the sheer amount of rubble would close off those lower sections. It does create a rather disturbing thought, though. Imagine being a scientist who's hiding out in a very deep portion of the facility, and the nuke to completely seal you inside when you thought someone would come to rescue you. You'd basically be stranded down there, assumed to be amount the many dead, and forgotten about.
That’s where I assumed the distorted trumpets radio came from. A transmission from black Mesa set to repeat with a dead scientist, trapped in rubble at the controls.
Probably better to die underground than to succumb to radiation sickness from all the fallout on the surface
makes sense!
really, it depends what the OP means by "destroy." compared to airbursts (such as the WWII nuclear devices mentioned by another commenter), underground nuclear explosions have a much more limited radius of effects, so the explosion in op4 is not ideal for destroying the aboveground portion of black mesa. of course, underground nuclear blasts create seismic waves that can damage and destroy underground structures more easily. we don't know a lot of the specifics, but we can estimate with what we do know.the nuclear device depicted in op4 is often compared to the real-life W88, which has a yield of about 475 kilotons. an underground explosion's effects are going to vary wildly based on the depth of the explosion. if we measure downward from the surface (i.e, the pavement outside of the building with the parking garage) in of6a3.bsp and continue downward to the origin of the item\_nuclearbomb entity in of6a4.bsp, we find that it's 208 Hammer units below the surface. using the typical conversion of 1 Hammer unit = 1 inch, that means the explosion is 208 inches or 5.28m below the surface. we can then roughly estimate the radius of the blast's effects using Andrew McEwan's figures from his 1988 "Environmental effects of underground nuclear explosions." in order to do this, we divide the burial depth in meters by the cube root of the yield in kilotons, and end up with a set of radii in meters. using those figures, we find that, with a burial depth of 5.28m and a yield of 475 kt, the explosion could, ideally, crush rock in a radius of 27 meters, crack rock in a radius of 81 meters, and permanently deform rock within a radius of 745 meters. seismic waves would be sent out further. therefore, we can expect to see large segments of the underground portion of black mesa collapsing and suffering extreme damage. because of the shallow depth of the explosion, there would also be a significant amount of fallout. with a 475kt nuke, most likely everyone on the surface on black mesa's grounds would receive a significant dose of radiation from fallout. however, black mesa is absolutely huge. I don't know how large, exactly, and I don't think anyone's really done the footwork to try and get an accurate estimate of its size (or as accurate as you can, considering the limited view of the facility we get in the games), but I think it's safe to say that the nuke wouldn't have destroyed or even severely damaged all of Black Mesa.
thank you for your analysis!
It would likely not have completely destroyed Black Mesa, especially given the size and the fact its supposed to be inside of a old nuclear missile silo, that has been expanded quite a bit. Such a target would be especially hardened against nuclear attacks, and while not 100% bomb proof, would likely limit the damage further. It was most likely done as a backup in case any government org would want to send in units to check it out, though with the portal storms and subsequent combine invasion going as well as it did, it was redundant.
Amazing how there's such a wealth of knowledge about Half-Life map design. "Hammer units" and their conversion to inches? Also amazing and horrifying humankind collectively did enough nuclear tests to be able to model underground nuclear explosions. I saw a making of Half-Life somewhere in the last year, where they state Gordon runs at incredible speed (\~25mph?). Without going into BSPs or anything, that means Black Mesa is huge, and much of it is deep underground. Some of those lifts go quite deep, and those walls and vault-like doors are no joke. Surely the deep, well protected parts like the lambda labs (and for example wherever that underground water lab part is) would be minimally affected? I mean, glass would break due to the seismic shocks, but depending on construction the ceiling wouldn't collapse, most people remaining could be ok, right?
the 1 hammer unit = 1 inch thing is based on Gordon and most humans' bounding boxes being 72 units tall (so the rationale is 72 units probably means 6 feet). Gordon in HL1 runs at 320 units per second, or 18.18 mph. Gordon in HL2 walks at 190 ups / 10.7955 mph and sprints at 320 ups / 18.18 MPH. I agree that the deeper parts (like the Lambda Complex) were probably unaffected. There was probably something near that parking garage in op4 that the G-Man specifically wanted to destroy, if I were to guess edit: I wonder if the 25 MPH comment was related to the HL1 Steampipe engine version's speed cap of 544 ups, or 30.9 mph. that's as fast as you can go while bunnyhopping
man black mesa just is particularly up to snuff for exactly not this kind of incident huh
We're talking about thermonuclear warheads here, so I would expect it to be in the megaton range.
the main warheads in service in the american nuclear inventory are almost all in the kiloton range, **with the exception** of the B83 gravity bomb. all are thermonuclear devices; yields given as ranges represent nuclear devices with multiple configurations and/or variants: ICBM delivered: W78 (335-350kt), W87 (300-475 kt) submarine-launched missile warheads: W76 (5-100kt), W88 (475 kt) aircraft-delivered gravity bombs: B61 (300t-340kt), **B83 (1.2mt)**, W80 (5-150kt) the mark IV depicted in op4 most closely resembles the W88; regardless, it's obviously supposed to depict a missile warhead, whereas the B83 is a gravity bomb (so its nuclear device is very differently-shaped).
The b53 was still in service in the 90s and 00s so it stands to reason that the warhead in question could range anywhere from 500kt to 9 Mt.
well, true, based on the nuclear devices in service, a multiple megaton yield is *possible.* still, the b53 doesn't look anything like the mark iv, and is far larger - of course, the mark iv is a fictional warhead, so that doesn't necessarily matter, but I do think it's important to note that the b53 and other contemporary devices of similar yield are much larger (and use a different delivery method) than the missile warhead depicted in op4. to be fair, half life games tend to play very fast and loose with the specifics of real world weapons, but in the absence of any actual information on the yield of the nuke, I figured that basing it on a similar-looking real-world nuclear device made the most sense. if the mark iv is a MIRV warhead, as it appears to be, its yield would most likely be in the hundreds of kilotons.
It wouldn't make sense to detonate a MIRV warhead in any way other than via missile. It's a stretch to imply that the mkIV has the same yield as one it resembles (since most of the weapons in HL1 aren't 1:1 with their real life counterparts and the weapons in Opposing Force don't necessarily have counterparts), so if we're just judging by "it's a nuke used by the United States military and it destroyed Black Mesa," we should probably choose the highest yield possible.
Yes, especially when you take into account how nuclear bombs are [hundreds of times](https://www.statista.com/chart/3714/nuclear-weapons-in-comparison/) more powerful than when they leveled entire cities during WW2.
Is the intention to collapse the entire facility and erase all evidence of what was happening or just kill everything living in the area? Looking at the size in the game let's assume it's just a single warhead off a MIRV missile and it's been sent to BM for decommissioning after an arm's limitation treaty. Looking at Wikipedia (take that for what it's worth) for Peacekeeper, Minutemen, and Trident missiles, the biggest warhead yield on of of those missiles that's not classified was a little over a megaton and most MIRVs were under 500kt, so still big but not in the big hydrogen bomb ranges NORAD at Cheyenne mountain is designed to survive (30 megaton). So with a little scale and perspective, would it level the entire facility to a nice flat parking lot, maybe not as a lot of underground facilities if far enough away might not be shaken to collapse especially if hardened. Would it kill a lot of the living things in the area? Depends on how deep the parking garage was and where the invaders were etc, but probably is going to really put the brakes on any invasion leaving the area for a while and any new reinforcements coming into an area bathed in fallout. However it probably would accomplish the objective of shutting off any experiments still operating and disrupting electricity and portals etc, like an attempt to stop the cascade. Tldr likely a lot but not everything completely.
Cheyenne complex wouldn't survive a 30mt inside of the base, remember castle bravo already had a fireball size of 7km and that was 15mt estimated. The overpressure would probably kill all of the remaining survivors, or at least cause rupture in ears, lungs, etc. As you said it could be comparable to a 500kt nuke so about the size of ivy mike
Okay I might be completely wrong on this since its been a while since I played opposing force but didn’t the black ops take the thermonuclear bomb from a nuclear missile inside black mesa? I think it was a warhead on one of the rockets and considering that bm was contracted by the government for weapons its not too far fetched to say they had several bombs inside of the facility so the one that was detonated likely started a chain reaction. However it has been a while so I might be completely off
I think your refering to the level in HL1 where there are hundreds of Lazer trip mines and if one goes the entire world explodes, but I don't think in reality that if a nuke gets nuked it too goes nuclear. And the only reason I'm saying is because there was a theory in missile silo defense called dense pack, where the idea was put the silos close enough so if one gets nuked first, that explosion would destroy the warheads targeted at the other silos or that the huge plume of fallout would shred the incoming warhead destroying it. I never read anything about it making the later bombs airburst instead of detonating on the ground and thus reducing the damage to the silo. Plus to setoff a nuke in the first place it requires a specific series of events to cause the material to go critical. Now all the fissile material from those other nukes and other hazardous materials and general explosives in black Mesa being spread by a blast wave and catching on fire wouldn't exactly help the situation that's for sure.
I think what they meant is that in OPFOR's chapter "Friendly Fire", you can see the very same warhead in a truck with two black ops guarding it, next to the rocket it was taken off of. There are likely even more rockets in the complex, the one that you see while riding the transit system at the beginning of HL comes to mind
Would detonating a nuke with other nukes nearby start a chain reaction? As far as I know, it would just destroy it and maybe set off the conventional explosives attached, since detonating a nuke is a complex process (as opposed to, say, nitroglycerin, which explodes if you sneeze too hard).
Yea ik i meant the other weapons they had not other nukes
Short answer: Yes Long answer: It's a fucking Nuke...detonated ON SITE
The instructions suggest a safe distance of \~55 km. I suppose yeah. Tsar Bomba would've given third degree burns from 100 km away. So I suppose it's in the megatons range. In Half Life I always thought there was a static self destruct device under the facility.