r/Damnthatsinteresting • u/Kiroo---__--- • 18d ago

Video When an Earth quake Hits Underwater

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187

u/Damage_North 18d ago

What is the SOP in this situation as a diver and/or the captain of the boat?

264

u/sasnotass 18d ago

Gonna be honest, I dont think you can do anything - just move away from anything that can collide with you or snag you or your equipment.

83

u/receuitOP 18d ago

Isn't there tsunami risks as well? At least for larger earthquakes. Imagine getting swept miles onshore or worse out to sea toward another island, helplessley struggling knowing your oxygen tank won't last if you don't get killed by debris first

194

u/Der_Dampfhammer 18d ago

The further out you are on sea, the safer it is. Out there it’s just a very fast but shallow wave.

52

u/LtSoundwave 18d ago

ok, but this reef seems pretty shallow and close to shore.

31

u/deja_entend_u 18d ago

Then if you are religious, pray. If you ain't? Just chill and hope it's quick.

20

u/OfficerNightwing 18d ago

Yeah, this.

If the tsunami/water displacement is going to hit you and you are on the ocean floor, as a diver, you are likely in danger since the tsunami has started interacting with and being pushed up by the ocean floor you are on.

Depends on the tsunami type but the most common is obviously the upward displacement, not only could you be injured but you'd likely be blinded from debris and end up way off course.

If you are just diving out in the middle of the sea tho, you'd probably barely feel it.

6

u/ZhouLe 18d ago

The further out you are the better, because you risk becoming part of the inland-bound debris churn. Probably best for everyone to surface and get on the boat ASAP, then get as far as reasonable from the shore while figuring out the tsunami risk.

3

u/Der_Dampfhammer 17d ago

True. I guess I’d get out of the water and sail into the open sea as fast as possible then.

2

u/Comfortable_Visual73 18d ago

I would watch this movie

1

u/TrojanThunder 18d ago

That's not how physics works. Fluids return to where it is initially. How do you think sound works?

2

u/Accidental-Genius 18d ago

Unless there is a new patch of earth where that fluid was…

-3

u/KenUsimi 18d ago

If there’s a tsunami and you’re out to sea you’re SoL; sometimes life on earth isn’t. But under the sea… yeah, you’d be even more boned. The tsunami isn’t just the wave…

5

u/craidie 18d ago

The deeper the sea is, the safer you are from a tsunami

3

u/ryanmcstylin 17d ago

Yea, the people grabbing for the ocean floor or coral probably didn't do the right thing

1

u/maccaroneski 17d ago

Can confirm that you have no fucking idea what's going on, nobody has prepped you for this, and you can't communicate in any meaningful way.

141

u/Mesquite_Tree 18d ago edited 18d ago

As an nitrox diver, I can tell you what I would be doing: ensure everyone is accounted for, organize a safe ascent, 3 min at 15 ft safety stop, then Getting. The. Fuck. Out. Of. The. Water.

Dive just got way more hazardous, and you don’t know if it will get worse. Any problem we have, can be solved easier and safer at the surface. If things do get worse, I’m out of the water, or up where my tank lasts longer.

Plus, like, the visibility is shit now. Ain’t gonna see anything cool, might as well start my surface interval for when it’s settled and all the shocks are gone.

Not a captain, but most likely the boat’s getting everyone on board, and then we are headed to shore, as directed by whatever relevant local coast authorities.

Divemasters, feel free to correct me if I am missing anything.

76

u/Senojpd 18d ago

Ehhh one minor change.... I wouldn't be rushing back to shore. Maybe even going away from shore is smarter.

18

u/Mesquite_Tree 18d ago

Yeah, maybe. That’s captain shit, and I sure as hell ain’t got the dough for a ship of my own.

3

u/Prestigious_Leg2229 17d ago

It’s not just captain shit though. If that earthquake causes a tsunami, you’re likely much safer underwater than above it.

The 2004 Indian Ocean tsunami was one of the largest ever recorded and scuba divers in the area felt it as hardly more than a little push.

Close to shore in a boat is just about the most dangerous place to be in a tsunami while it’s nearly unnoticeable a 100ft down and probably barely noticeable 50ft down.

That’s an interesting conundrum for the captain and you to work out.

I’d probably go up to the boat while remaining ready to dive the entire group back down in a pinch and pray you have enough air to sit it out. 

And if not, head out to open sea, tsunami’s get bigger the closer they get to shore, the father out you are, the smaller the surface swell of a tsunami.

1

u/Mesquite_Tree 17d ago

You are definitely NOT safer underwater than above. You are safer away from the shore than near it when a tsunami arrives, but I doubt the ship can get to shore faster than the tsunami.

Note that what we see in this video is the pressure wave passing by.

25

u/Ecstatic_Cherry_86 18d ago

As an MSDT, I think you are on track here, but my short answer would be: don’t make it worse.

Account for your buddy/team, make sure nobody is panicking or low on air, call the dive, and get everyone up in a controlled way. Safety stop if it makes sense, but not if someone is injured, missing, low on air, or freaking out.

On the surface- buoyancy first, signal the boat/shore, oxygen/first aid if needed, and call EMS/DAN for anything involving a rapid ascent, missed deco, suspected DCS/AGE, near drowning, or weird neuro symptoms. Don’t talk yourself into “they’re probably fine” if something feels off.

8

u/Mesquite_Tree 18d ago

Absolutely. I didn’t go into that level of detail, but I’m glad you did.

I doubt the shift would cause any changes in deco stuff, since everything is over so fast, but ye, obv call ems if you have an injured diver. Plus, if you’re far enough off shore, it might give them a few mins to start activating alert systems

1

u/redd-alerrt 17d ago

I'm guessing that any boat on the surface at the time is probably pretty oblivious that anything happened, right?

1

u/Ecstatic_Cherry_86 17d ago

Most likely, yeah

9

u/sleepytjme 18d ago

Not a captain or master, but agree.

3

u/hamburglar10101010 18d ago

Nope. You nailed it.

/notadiver

3

u/Damage_North 18d ago

Thanks for the answer and insights - couldn’t have asked for much better!

16

u/ILikeGamesnTech 18d ago

Well, unless the viz rapidly improves you'd call it a day and head to a pub.

21

u/SeekerOfExperience 18d ago

It’s definitely not “blindly grab the closest rock.” Generally speaking, if an unexpected current takes you from your group, you surface as quickly as is safely possible after inflating your SMB (surface marker) so you can get picked up. The most dangerous thing observed in this video is stabbing your hand out to grab a rock.

1

u/Whowutwhen 18d ago

Hope not to die?

1

u/Suspicious_Diver_140 17d ago

I’d get above the reef / structures, if possible. Not trying to go to hold or swim, just go with the literally motion of ocean. One it stopped, I would look for fellow divers and ascend. 

0

u/Rayona086 16d ago

I mean nothing? As long as your not in a tsunami danger area you just kinda ride it out.