Signature of destruction - energy weapons

Question

As an additional follow on from Destruction by design - how best to go about crafting a ruined landscape? I'm asking some questions about signature destructive patterns. This is the second one, the first follow up deals with deliberate demolition type destructive processes and can be found here:

Signature of destruction - does tearing down a building leave noticeably different ruins to natural decline?

This question is about the ruins of war. Now, obviously we have a lot of good data about what most of our modern arsenal does to buildings, so I'd like to look at the use of orbital weapons and in particular energy weapons. What, if any, kind of diagnostic patterns of damage might we expect to see in a ruined city that has been subjected to heavy bombardment using space based energy weapons?

I feel that this should be answerable without excessive conjecture in light of the damage profiles of modern thermal cutting tools like industrial lasers and plasma cutters. anon's answer has pointed out that I should have made a note that the weapons are tactical rather than strategic in nature and as such they have a much smaller area of effect compared to nuclear or other weapons used to annihilate entire cities. In this case consideration needs to be given not only to reasonably fresh damage but also to how such damage may weather differently to conventional explosives with time. Please use the same 200 year benchmark as with the previous "Signature of destruction" question linked above.

Answer 1

Tricky to tell since the effects are very similar to conventional explosives

Incendiary and blast effects are the primary effects of orbital energy weapons. This is very similar to the effects of conventional explosives. However, there are some tell-tale differences.

Characteristics of Nuclear Bombardment

Nukes are easy to identify.

• Lots of radioactive isotopes spread all over the blast area.
• Large point crater(s) if surface burst.
• Wide spread thermal and blast effects
• For airburts, there's no crater but a large area where damage-sign radiates away from the blast point.

Characteristics of Conventional Weapons Bombardment

• Small point craters compared to nuclear weapons. Many many more craters.
• Lots of shrapnel and shell casings.
• Puncture of structures and armor in neat holes formed by the projectiles.
• Damage can come from almost any angle since bombs and shells can be fired to impact the target from low trajectories or high angle plunging fire.

Characteristics of Theoretical Orbital Energy Weapon Bombardment

• Many small craters similar to conventional explosives
• Elongated craters from where the beam weapon didn't stay focused on a single point but was "dragged" by orbital motion.
• No metal fragments of any kind.
• Penetration of armor won't be neat circular holes. When the energy beam hits the armor, particles will ablate away into a cloud which should defocus the beam and make it less effective. If the target material has any amount of water in it, then the water will flash boil to steam causing explosive effects.
• Damage will likely come from overhead. The less atmosphere you have between you and the target the better. Long atmospheric shots have to deal with aiming through thick moving layers of dust-laden atmosphere. Avoid that if you can.

200 Years later

Assuming that no one has come back to these ruins and changed something. The vegetation will have mostly healed by then but there will still be considerable changes to the 1 meter resolution topography. Walking through WW1 and WW2 battlefields, it's easy to see where battles happened because the land still rolls where large shells exploded.

Clues as to what happened are most likely to be found on the materials that don't change much in 200 years like weather resistant metals, stone or ceramics. If an investigator is lucky, they might be able to find a hard boundary between where the beam shone on a piece of stone, bleaching one side but not the other.

Answer 2

The type of weapon makes no difference. How it destroys does.

The weapons thermal output, or kinetic energy, pressure displacement, and other chemical aspects are all that matter in this topic.

The effects between a meteor and a nuclear warhead can be same with fallout and all.

So the difference between an orbital energy weapon and a terrestrial energy weapon would be largely the same. Being that these are energy weapons, Im assuming the mode of action is extreme heat. Given that assumption you could compare the effects similarly to an H-bomb. Rapid and temporary exposure to high heat.

Heres an interpretation of what an H-bomb would do to Seoul

You can also ignore fallout as an energy weapon would be different

You can potentially skip the bit of disintegration and go to the melting point. But this largely depends on your exposure time of your weapon.

An explosion of that magnitude over Seoul would cause structures up to 1,200 feet from the point of explosion to "evaporate". Buildings up to 1.5 miles from the blast would melt or burn, the report suggests, while anything up to 7 miles away would suffer massive damage.

Anyone caught 2.5 miles from the explosion would suffer third-degree burns and "no living being would survive such a catastrophe", the report added.

An area of Seoul with a circumference of more than 2.5 miles would experience total destruction, with fires raging across a further 11 miles in all directions.

This highlights the radial effects of a thermal weapon. Obviously its scale is largely dependent on the energy and target radius.

The area would appear much like a volcanic region with various melting's and glassing's. Just like volcanic regions plants would be able to return within 200 years.

Answer 3

Does this orbital beam weapon fire short, intensive beams or long, less intensive ones?

Consider something like a bomb-pumped x-ray laser. Presumably each target gets a single shot, even if many separate devices are employed globally. Energy is applied to a part of the target ("ground zero"), this part vaporizes or worse, energy gets transferred to the rest of the target, destruction ensues. Possibly the ruins are not much different from a small (conventional or nuclear) bomb.

Compare something like an industrial laser, even if it is pulsed. A shipboard laser weapon might be like this, only scaled up. Energy is applied to different parts of the target over time. Instead of one "ground zero" there are many different impact points.

So you can justify either decision, except that too little energy at any one time would get wasted in the atmosphere. That makes the first option more likely, unless you need the second option for dramatic reasons.

Answer 4

Most space based energy weapons would have a lot of difficulty with the atmosphere or earth’s magnetic field. Assuming these issues have been somehow overcome the energy weapons will provide huge local heating effect. This should be easily spotted in ruins.

Energy weapons would be far more likely to ignite all combustible materials in the vicinity than conventional high explosives and could be distinguished from nuclear weapons by the absence of radiation.

Energy weapons would almost certainly create a large degree of melting which should be detectable in ruins. Melted or heat distorted metal fittings would be seen everywhere; aluminium might well catch fire in extreme heat and would leave tell-tale white aluminium oxide marks. Smaller metal fittings might be reduced to solidified blobs.

Energy weapons would be capable of melting other house components such as windows and perhaps fusing some ceramic materials. All of which would make it very clear what had happened.