Can you feel an earthquake if you're in a cave? Is it safer to be in a cave during an earthquake?
There is nothing different about a cave that would make it immune to the shaking from an earthquake. Just as there are safer and less safer places to be on the surface of the earth during an earthquake, there are also various characteristics inside caves that make some cave locations safer or less safe than others. First of all, whether or not you feel an earthquake in a cave depends chiefly upon the magnitude or size of the earthquake and the distance from the earthquake source to the cave in question. The closer and larger the earthquake, the more shaking you’ll feel. The rest of the information about cave stability and shaking effects is based on limited observations and is a major area of active research.
The complexity of the cave seems to be a very important factor with regard to issues of cave passage "stability". A small tube-like passage appears to be a relatively safe location that doesn’t tend to collapse or sustain much, if any, damage from earthquake shaking. However, large cave passages or “rooms” are notably less stable places. It is in these areas where fallen chunks of limestone or marble are commonly observed, and where broken or toppled cave formations tend to be found.
Shaking effects inside caves include damage to delicate formations like soda straw stalactites that effectively “die” and top growing. Sometimes stalagmites or columns can be toppled. Toppled or not, renewed growth on them can occur. These effects are far short of a total passage collapse, but collapse of portions of cave ceilings has been observed in caves, notably from caves in Missouri and Indiana near the New Madrid and Wabash seismic zones.
So are caves safe in earthquakes? Generally yes, but it depends on the cave characteristics and where you are in it.
An interesting note: Cavers who witnessed earthquakes while underground have described sounds as if a distant aircraft was passing by, as in becoming perceptibly louder, then fading away.
Why do earthquakes in other countries seem to cause more damage and casualties than earthquakes in the U.S.?
The central United States has undergone a dramatic increase in seismicity over the past 6 years. From 1973-2008, there was an average of 24 earthquakes of magnitude 3 and larger per year.
PORT-AU-PRINCE, Haiti — The severe damage and loss-of-life caused by the devastating January 2010 M7.0 earthquake in Haiti was exacerbated by amplification of shaking due to local geological conditions and landforms in Port-au-Prince, according to a study published online today in Nature Geoscience.
The U.S. Geological Survey (USGS) announced today the release of new public web pages that show the probability of earthquake shaking in the next 24 hours in California. These maps graphically illustrate the change in earthquake probability during aftershock and possible foreshock sequences.
In conjunction with the seventh anniversary of the 1994, 6.7 Northridge earthquake, the U.S. Geological Survey, in cooperation with the Southern California Earthquake Center (SCEC) and the National Science Foundation (NSF), has produced a two-page fact sheet that explains how geologic conditions in the Los Angeles basin affect the amount of shaking experienced by various areas of the basin.
What do eyeless worms, bacon formation draperies, and soda straw stalactites all have in common? Do you know the difference between a troglobite, a trogloxene, and a troglophile? Where do you go spelunking? Find out the answers to these and other questions in the new U.S. Geological Survey (USGS) publication, Exploring Caves, a teaching packet for grades K-3.
Arch Cave in Zion National Park. Although not yet a full arch, the processes by which arches form can be seen here.
The natural entrance of Carlsbad Caverns.
These sections of the Caverns of Sonora were carved by the wind, rather than by water. As such, they have smooth walls.
The Herrenbergberg Cave in Germany was discovered during the process of digging a new high speed train tunnel. Before its discovery, it was isolated from the surface.
For more information see: https://water.usgs.gov/nrp/microbiology/research/pristine/pristine.html
Insights from southern Sierra Nevada caves and karst
By John C. Tinsley, Geologist
- Water long ago carved many caves in carbonate rocks of the Sierra Nevada
- As the Sierra (John Muir's "Range of Light") was uplifted, successively deeper caves were drained and decorated during the past 5 million years