Over at Tai Wiki Widbee, there is a post that references an incident in 1965, where teenagers went diving in the hole and two drowned. The story of that is very interesting, especially that they never recovered the bodies, because the hole is so deep - perhaps over 900 feet! And there is a current down deep! Here's the story:
In Death Valley National Park, Devil's Hole is a tiny spot of water in an otherwise desolate and inhospitable environment. It is home to the only population of the Devil's Hole pupfish, which lives in the top few feet of this pool of water. They are rarely found more than 2-3 feet from the surface, but the maximum depth is over 300 feet.
One night in 1965, several kids jumped the fence and got in. Two never came back out, although divers attempted to rescue them in the event they were stuck in an air pocket called Brown's Room. They weren't.
Nobody knows precisely how deep Devil's Hole is; tethered weights go to at least 485 feet, with more to go.
David Rose and Paul Giantontieri entered with friends, but never came back out. Jim Houtz reconnoitered to a depth of 315 feet, then a record, but found no bodies, only a dive chart and a fading flashlight.
I also led a rescue there in 1965. There were four youngsters – teens who climbed the fence. One was a Senator’s son. Three went in the water and one got some sense and said, ‘I’m not doing it.’ They did this at night. Once you round that first bend at ninety feet – you don’t know what dark is until you go around that bend. There’s no reflection down there. The walls are limestone. They look smooth, like clouds, but they’re rough. Rub your hands against it and it’ll take the skin right off.So I was at the Newport Harbor Yacht Club giving a presentation on diving – I have sixty, seventy people and a call came in from the Federal Government. They said, ‘are there any air pockets in those caves down there?’ and I said ‘yeah.’ I get up to Los Alamitos with my guys and this seaplane – a Grumman Albatross was on the runway, engines running. Next thing you know, we’re flying and the hatch isn’t even closed. We tried to land in a place called Ash Meadows on the California/Nevada border, but the plane had to come over a mountain and drop over a very short runway – the pilot tried three, four times and he couldn’t do it.So we get there from Nellis Air Force Base at daybreak – the media was out in full force. The military, state police. Even a big trailer that served food. We had four guys. I set up my first team of two guys (Author’s note: one of those guys was a diver and Vegas nightclub singer named Harry Wham, who, unbeknownst to Houtz had accompanied Mel Fisher on a failed treasure dive to Cortes Bank in 1957, and would later be murdered by family members in 1981.) and we went in increments – with divers at two junctions to handle decompression issues. I get down into the lower chamber – and there I found a mask with a snorkel on it and a fin. Later I found another item from the other diver. But the point is, when you get that deep, you get nitrogen narcosis. Nitrogen poisoning. It’s a drunken state, and you get lightheaded. Once you get that, it’s far more probable that you’re going to do something stupid, because you feel there’s nothing you can’t do. The only reason I was able to make these dives was because I’d been training for it – for the narcosis.I went to the surface and notified everybody about what we found. It was a very sad, very solemn moment. I said, ‘I’m going to recover the rest of this equipment and I’ll do one more thing to confirm. So I made one dive to the last little ledge – at 325 feet. At that point, the Devil’s Hole opens up wide, and I can tell you one thing. I know it goes down to over 900 feet. We once let out 932 feet of cable from that point and there’s a current down there – so how much of the cable was bowed from the current, I don’t know, but it’s just, it’s just massive. But down at 325 feet – that’s where I found the remainder of some of the gear – right there, just as big as life. I’m sure that’s where the kid wound up – in the very far depths. He just kept going down. The guys were never found. The only thing down there now is bones.
No other sources seem to reiterate what Jim has to say about a depth of >900 feet, and in limestone (a very soft rock) that seems unlikely, but stranger things have happened.
Anyway. It's tough to even find good information on the accident these days as it's largely been forgotten. Maybe someday some ROV will find the remains of those two divers.
So, perhaps what we have here is a huge column of water, the depth of which is still unknown, but which acts as a device to sense long wave vibrations from distance earthquakes in the crust. Man, how much fun it would be to send a submersible into the hole to see what is really down there, and how deep the thing really is.