On my vacation I visited a cave. Our guide informed us that during an earthquake a cave would be safer than above ground. Seems to me this is something a spelunker would want to believe, not something he should believe. So is a cave really safer than the surface during an Earthquake?
When the ground is shaking and heaving, why would a location with tons of rock - of uncertain structural quality - overhead be considered safer than a location with absolutely nothing overhead?
where would we get the relevant statistics from? How many people were in caves during earthquakes and either survived or got dug out dead for us to make conclusions? Or should we study the earthquake damage to caves after earthquakes without people inside and try to infer/guess whether this level of damage would have killed the people if they were in there?
Tangentially related, during 1556 Shaanxi earthquake - Wikipedia there was a staggering death toll involving people living in “artificial” caves made in easy-to-carve soil. Perhaps our “real” caves are very different from that.
In a small passage dissolved out of good limestone? A pretty solid (heh) yes.
Big passages in crappy limestone, probably not as much as being on the surface outside of a building, but maybe better than being a big building thats experiencing a quake thats nearly as strong or stronger than the quake it was designed to withstand. I’d take may chances in just about any cave anywhere rather than a collapsing building.
People tend to think caves are on the virtual verge of collapse. By definition, they are around for geological ages (10s to 100s of thousands of years, if not more or even way more). If they were that fragile, they would be nothing but rubble piles/depressions in the ground. There ARE caves like that, but they are in the small minority.
From the Mammoth Cave website:
I’ve heard this theory many times on cave tours. The the biggest danger (they say) is that the earthquake would cause a landslide and bury the entrance.
I’ll take my chances outside, in the parking lot vs. underground, staring up at the stalactites.
This may well be so, but doesn’t explain why being on the earth’s surface away from anything that might fall on you would be worse.
bolding mine.
Not everywhere on the surface is like that.
Most places in a cave arent so weak at any given time that all its gonna take for stuff to fall down is a quake.
While that’s true, you don’t have to experience a total collapse to get injured in a cave. One tumbling rock, dropping from the ceiling, and you’re now in your very own geologically-significant tomb. Or of course the chance that you’ll lose your footing and take a tumble. Nah, I’ll take a wide-open field of soft grass over a cave. Unless said field is near a volcano, or something…
My thought exactly. Earthquakes themselves are harmless. People get killed when things fall. So the safest place you can be is in an open field with solid ground under your feet. I don’t doubt that caves would be safer than office buildings, but not safer than “above ground” in general.
True. But the ratio of people with easy access to an open area vs. those handy to a cave has to be rather impressively large.
Well, I wonder about the context of the statement related in the OP.
IME, someone on the cave tour usually asks “What happens if there’s an earthquake while we’re in here?” The guide usually has an answer along the lines of the quote from the Mammoth Cave website. I don’t think they meant, “A cave is the safest place to be in an earthquake.”
Yeah, I’ll take a wide open field too. But what if I am in the city, or in traffic, or surrounded by trees, or next to tall buildings? Gets a little a little more fuzzy quickly IMO. IN buildings and most places in most caves are probably safer IMO.
You’ve seen too many hollywood movies. I am sure statistically speaking one rock falling doesnt magically seal a cave like cork. Nor are you likely to be right under the rock that falls.
don’t forget that sometimes that nice open field cracks open.
i would think in some sort of aircraft, in flight would be safest.
Opps, I fogot about that. And they are often cracks in dirt/soil that are very likely to fill right back in soon. Not good if you fall in one.
Let me try this again.
Pick a place in a cave. Ask a geologist how long its been since something fell from the ceiling there. Their answer will be “a long damn time”.
If the quake you are experiencing isnt the strongest in a “long damn time”, chances are small that something is gonna fall for this particular quake. And in plenty of places in plenty of caves the geometry and geology is such that anything falling is very low short of actual explosives placed there.
Keep in mind, long damn time is anywhere from hundreds to thousands or more years and probably way more than that.
So out of curiosity, are you and the geologist wearing hardhats while you look at the ceiling of this cave? If so, why? Every show I’ve seen with people exploring caves (as opposed to well mapped caves) everyone’s wearing hardhats.
It’s in case you hit your head on a low passage or slip and hit your head on the rocks. As a tall person I should probably wear a hard hat just going on a cave tour.
Here’s a link to a (PDF) of a newsletter that has an article that’s a little more in-depth (yuk yuk) about earthquakes in caves: http://www.nps.gov/wica/naturescience/upload/RM%20Ramblings%20Fall%2008%20v.%206%20n.%208.pdf
Yes. But its MOSTLY to have something hold the light rather than your hands. Try climbing, crawling around, or trying to do something like reading, working with gear, or writing while holding a flashlight in one hand. It don’t work well at all. In a distance second, its to keep from you bumping your head on something by your own doing. A more distance third is to protect your head from small rocks falling long distances, like 100 foot deep pits, and usually caused by human activity in the first place (like people dicking around above you).
Spontaneous rockfall is rare (though people have been killed by it).
And those helmets do nothing to protect against those big human bug squashing rocks everyones seen from Hollywood.
Folks do not wear helmets in caves because they are in imminent danger of collapse.
Note that artificial mines and manmade “caves” are nearly the exact opposite.
Sure if you’re in the city and you have a choice between, say, a parking ramp or the cave next store, go for the cave. OTOH, if you’re between them, don’t go into either.
Also, if a cave is packed with people sheltering from an earthquake and a big rock falls from the ceiling, odds are someone is going to be under it.
I’m guessing that there’s a good reason that I’ve never heardof underground earthquake shelters, or above ground ones for that matter. Except for these.
Now your are just being silly. Who the said caves should be earthquake shelters packed with people?
And if everyone packed into a non-earthquake designed big building and it collapses most of em are going to die when it collapses.
Let me reitertate. IMO, unless its the biggest mofo earthquake around since before the Indians got here, statistically speaking you are not going under that big assed rock that falls in a cave during the quake.
And besides, if you are in a cave, the biggest danger is by far the big rooms.
Anybody with any sense would run for the walls or smaller passages, where the danger from rockfall is greatly lessened, if not virtually non existent.