I'd think it obvious that an air cannon isn't going to produce sound levels equivalent to an atomic bomb.

Considering that air guns are powered by air compressors typically driven by diesel engines consuming a couple of gallons per hour, the average power isn't that high. The peak power is higher, because the guns fire in pulses, using the air as a storage medium.

The oscillating bubbles created by air cannons are practically microscopic by comparison.

For seismic analysis, particularly for differentiating between oil-filled rock, gas-filled rock and water-filled rock, we need lots of high frequencies in the projected sound, so that we can measure the difference of absorption at different frequencies. To get those high frequencies, we need bubbles of relatively small size. That constrains the power we can put into the water. Producing bigger guns will produce more power, but will not answer our geological questions, and so would be a waste of money. We'd have to run multiple surveys (big guns versus small guns) across the same area, almost certainly causing more harm than doing one survey.

See my comment up-thread. TFA is ill-informed and written to generate FUD, not to inform people. These aren't new techniques, and procedures for mitigating the effect of seismic air guns on sea life - particularly cetaceans - are well-known and used throughout the industry.

But in the absence of being able to issue warnings in "dolphin language"

The "cetacean communication experiments which were stopped were ones attempting to teach dolphins (I forget the species, but only one species) to speak English. Work to understand the communications of cetaceans continues to this day.

Your "dolphin language" phrase implies that you think there is one "dolphin language" ; what we're pretty sure of is that there is one language per species ; there are 40 "dolphin" species in 17 genera (closely related groups), and about the same number of other cetaceans. We're pretty sure that some species have multiple, geographically constrained languages - "dialects" if you will. So your "dolphin language" suggestion implies learning to speak something like 100 distinct dialects, some probably very distantly related to others.

Big task.

See my comment up-thread.

You don't know the procedures that have been followed for years. I first approached my Boss about getting qualified as an MMO in about 2005, but he couldn't see a business case for it - I don't have the time in my regular employment to spend 1/2 hour doing nothing but sweeping the horizon with binos.

Shame - I'd have liked to get paid for a week of going whale-watching.

Those figures sound broadly comparable to regulations that I've seen controlling the exposure of diving workers to loud noises in their work place (pneumatic tools, stand-off distances from explosive cutters, that sort of thing). I didn't memorise the details as I didn't need them, but those figures sound broadly comparable.

There's no point to sitting in one area and pulsing the same place over and over.

There is - if you're doing "Seismic While Drilling". You can bump up the signal to noise ratio at your hydrophone 5, 6, or 7 kilometres below the seabed, without having to use huge air gun arrays (the compressors and air banks for which take up a lot of deck space ; deck space is always at a premium).

However, TFA is about shooting area-wide seismic coverage, not SWD. Because of the turning circle of (say) a 5km long, 16-wide array of streamed hydrophones, you keep them in constant motion. If you didn't, the hydrophones will get displaced from their required relative positions. Positioning typically needs to be precise to tens of centimetres. (Yes, many companies use (D-)GPS to confirm the positioning of the hydrophones, and record those positions for every shot.)

I mean, people have been detonating underwater *atomic bombs* - how do you think that compares to the sound of a pop of air?

Just to put this into perspective : the air guns are suspended over the side of the drilling vessel about 20m from the side of the vessel ; if they're streamed behind a seismic boat, they're in the order of 100m behind the boat.

Shocking as it may seem, we don't design equipment that will damage our other equipment. Which is why the energy released from air guns is considerably lower than (for example) that released by a depth charge or a torpedo.

Can they give "warning shots" for some time period ahead of time to clear the area?

We call them "mitigation shots".

I don't know American regulations, but Norwegian regulations require a visual observer ("MMO", Marine Mammal Observer) to scan for cetaceans (whales, dolphins) by day and an acoustic monitor ("PAM", Passive Acoustic Monitor) to be deployed for at least 30 minutes before starting the guns. If a cetacean is spotted within a kilometre of the air guns (why they're using the name "sonic cannon" except to drum up FUD, I don't know), or an acoustic detection is made, then a start up sequence of one shot every 30 seconds, ramping from zero power to operating power over 30 minutes. The specific aim is to alert the cetaceans to something noisy happening, and to impel them to move away.

(I don't have a qualification to operate as an MMO, but I have to work with them on almost every exploration well that I drill, and I am absolutely flat-out no-questions-asked required by my employer's to comply with the MMO's recommendations. Here is a list of the exceptions : [LIST BEGINS][LIST ENDS] ; list length 0 bytes. Can I be less ambiguous about this?)

This is NOT new technology. The mitigation procedures are NOT new. TFA is pure FUD.

No, for domestic workers.

Well, "domestic" to those of us living in Scotland, Norway, Nigeria, Netherlands, Lithuania ...

After all, we've seen what Americans can do when they're trying to drill holes in the ground offshore America; we're hardly likely to do worse.

I am from the Netherlands, where most of the casualties are from: can we PLEASE stop our uninformed finger pointing until at least some evidence turns up?

You're doing that Dutch thing of being all reasonable and calm when less self-controlled peoples (particularly Americans, but not restricted to them) would be running around screaming like headless chickens, and calling for the nuking of any and all countries alleged to be involved, before actually getting any evidence.

How can you have such calmness and self-confidence, when people less involved know that you should be beating them to the peaks of hysteria.

And people wonder why I like working with Cloggies.

there are two flight recorders

There are two data recorders on civilian airliners, which record different things : a flight DATA recorder (FDR) and a separate cockpit VOICE recorder (CVR). Though quite what new data these would provide is not at all clear to me. Do you think that the alleged Ukrainian fighter plane would have been in conversation with the plane or something? Why would they do that? What's the FDR going to contain? [Flying][More Flying][More Flying]All hell breaks loose, with many sensors and/or power and/or hydraulic buses going down. That's going to tell us that the plane wasn't CFIT by a mad pilot (which is an allegation I've not heard from anyone), and that there wasn't piecemeal falling apart of the plane because the welders were pissed the day they built that airframe (another allegation I've not heard). So what new information are they going to add?

I've never heard of any aircraft carrying two FDR and/or two CVR. Unless you know differently (citation, please). They're expensive bits of kit and take non-trivial maintenance, so only the minimum required is fitted.

What data did the FDR record? That's up to the operator - after the 88 parameters required by FAA specifications. (I assume the FAA requirements will be a minimum, as the airframe was by Boeing, so has made at least one flight originating in the US, and therefore subject to FAA regulations ; it may never have been subject to FAA regulations since, but re-programming and/ or re-wiring the FDR to comply with some other relevant standard would be a significant maintenance task, and why spend the money. I checked the FAA's standard here, and to my surprise they refer back to a European standard "European Organization for Civil Aviation Electronicsâ(TM) (EUROCAE) publication ED-112, Minimum Operational Performance Specification for Crash Protected Airborne Recorder Systems" ; if you want to follow the paper trail, feel free.)

CFIT - one of the most terrifying of aviation acronyms : Controlled Flight Into Terrain.

Oh, and why have I been "accused" of being an American?

Because you're posting on Slashdot, which has a large majority of Septics with their typically abysmal grasp of the world outside America.

Yep. It'd be in shadow all the time which means it would be perpetually cold. 26 to 35 Kelvin cold.

Not so. From Wikipedia :
Surface temp.
min mean max
Equator 100 K 220 K 390 K
85ÂN [6] 70 K 130 K 230 K
(Near-surface) cave systems internally attain the mean temperature of their surface environment over a period of decades or centuries (depending considerably on the rate of heat movement by air flow ; negligible in this case). So a mean temperature of 220K is comparable to the Antarctic Plateau stations in winter, but doesn't have the wind chill. The 85deg N station shouldn't be much of a problem.

Our experience (an important word and concept that) with space stations of various types, from the Apollo 13 use of their lunar lander as a lifeboat to the present ISS and Tiangong 1 space stations (and the planned Tiangong 2 and successors) shows that temperature control is not insurmountable, at which point, the radiation and meteorite shielding becomes more of an issue.

It is possible that there have been human-like creatures before, they evolved, left the planet,

You missed out the bit about cleaning up every sign that they'd ever existed. Which is not a trait that any human society has ever had.

Which is code for "extremely cold all the time".

And managing "extremely cold all the time" is much easier than having to manage rapidly changing temperatures.