Welcome to the Kazumura Cave Preserve website.

On this page you'll find a great deal of information about: Kazumura cave, cave preservation and land development above a cave. Topics are presented in a collapsed format. To display a section or photo, click on the green arrow next to the title. To re-collapse, click the blue arrow or the photo itself. To display the answer to a question click on the question. To hide the answer double click the answer.

Why Kazumura Cave is Important


If you've done any research on Kazumura, then you already know that the cave is a national treasure because of its length and depth. What you probably don't realize is that Kazumura may also be the world's most geologically diverse cave. Of the possible types of formations found in lava caves, nearly all can be found in Kazumura.


Kazumura's biological diversity could be just as significant. Most cave creatures are dependent upon above ground food sources. The type of food available can change with elevation. An organism living in one area could therefore be replaced by a better adapted species in a another area. In this way the biodiversity of a long cave like Kazumura could be greater than in a smaller cave.


In addition to its geology and biodiversity, Kazumura also houses several important archaeological sites. These sites provide insights into the lifestyle of the Hawaiian people.

Hazards to a Lava Cave

Natural Hazards

Fire - Radiant heat from a lava flow or fire can kill cave organisms which are unable to evacuate the affected area. Organisms dependent upon surface vegetation will also perish as their food supply is burned. Fire can even spread to the cave itself through the roots of the ohia tree. The Hawaiians used this fact to smoke out or suffocate their hiding enemies.

Lava seal - Lava flowing into a cave entrance can seal that entrance. If a cave's only entrance is sealed, organisms which rely on flying insects being blown into the cave will perish.

Water - Sediment carried into a cave by dripping or flowing water can in time, fill the cave.

Wind - Wind storms can blow down dead or unhealthy trees. The ohia tree's roots grow through the rock. A blown over ohia can pull up, the rock was rooted in. If the tree sits above a cave the roof can be thinned or removed.

Earthquake - Earthquakes are surface waves which may lead to a collapse of a cave ceiling; but only if the cave is close to the surface.

Human Induced Hazards

Bulldozing - The biggest hazard to a lava cave is bulldozing. As a bulldozer clears a lot or roadway of vegetation, trees are pushed over and the rock the trees were rooted in is pull up. This thins the roof of any existing cave from the top. The bulldozer then goes back over the cleared area crushing the remaining rock to level the area. This process further weakens a cave roof from the top. The vibrations from this process can also cause collapses in the cave thereby thinning the roof from below.

Aside from weakening the roof, debris from the bulldozing process can can be washed into the cave through created openings. This can drastically change the cave environment.

The loss of surface vegetation ensures that organisms dependent upon those plants will die. This in turn could cause a ripple effect through the cave's food chain.

Jack hammers and blasting - Most areas on the Big island of Hawaii have little or no soil. Because of this, a hole for a cesspool or septic tank must be made in the solid rock. These holes are either blasted or dug with a jack hammer. The vibrations from either process can weaken a cave roof causing a collapse.

Jack hammers are also used to install fence posts.

Generators - Many home owners use generators to power their homes because hooking up to the grid is too expensive. The constant vibrations from a running generator can dislodge loose rocks from a cave ceiling or wall. This is especially probable if the area has been bulldozed.

Road traffic - The vibrations produced by moving vehicles can be heard for quite a distance in a cave. As with the generator vibrations, road vibrations can weaken the cave roof.

Vandalism - Cave vandalism can range from spray painted walls to the deliberate destruction of rare cave formations.

Dumps - Although the practice is illegal, some cave entrances have been used as trash dumps by individuals too lazy to dispose of their trash properly.

All of the above and more - Human activity on the surface changes the type of organisms which can survive in a particular area. This in turn can lead to the demise of cave organisms which are dependent upon that specific environment.

Questions related to Land Development Over Caves on Hawaii Island

Do bulldozers ever fall into caves?

Yes. It happens often enough that there are set procedures to remove them.

What sort of problems are created when a bulldozer falls into a cave?

• If the drop is big enough, the operator could be seriously or fatally injured. A big drop would also complicate any rescue attempts.

• If the bulldozer is wedged in, the operator could be trapped. Not to mention that the bulldozer becomes a permanent fixture on your lot.

• If the operator is OK and the bulldozer can be removed, a second machine may be needed to assist in the removal. Several truckloads of fill may also be needed if there is not enough loose material around to build a ramp from the bottom of the cave to the surface. The removal process can take days to complete.

• Many land owners then choose to fill in the hole, so many more truckloads of fill may be necessary.

Are there any alternatives to bulldozing?

One could argue that a smaller machine like a backhoe with front end loader is less destructive than a bulldozer, but both machines push over the trees in the same manner. The only way to maintain the integrity of the rock is to hand clear.

What are the advantages and disadvantages of hand clearing?

  • Advantages
      • The integrity of the rock is maintained.
      • Impact to a cave is minimized.
      • Only the areas you want cleared will be cleared. (Bulldozer operators often clear the entire lot unless the land owner is around to say otherwise.)
      • The landscaping is done before you build.
      • Fossil fuels are not being used to destroy oxygen producing plants.
      • The cost is limited to time and tools.
      • The time you spend clearing allows your savings to grow.
      • When you do build you can fasten the foundation directly to the rock. This prevents a structure from moving during an earthquake. It also prevents the structure from sinking as filled in areas settle.

  • Disadvantages
      • Hand clearing takes a great deal of time. The weather will likely prolong the process.
      • Its hard work. The under-brush needs to be cleared before you can even get to the trees.
      • Do collapses ever occur after structures are built?

        Yes. In one instance a lot was cleared with a small bulldozer. While clearing the operator felt his machine bouncing in one area. A year later, after a home had been built, a massive hole was discovered where the machine had bounced.

        What causes collapses so long after the lot is cleared?

        There are many possible answers to this question. Collapses can be initiated by vibrations from; a bulldozer, a generator, earthquakes, roadwork, heavy traffic, blasting or a jackhammer. A collapse could also be the result result of: heating and cooling cycles, fluctuations in rainfall, or a lightning strike.

        If I know a cave is under my property can I still build there?

        Before making a decision, learn as much as you can about the cave. At the very least you need to know the cave's location, depth and roof thickness under you property. You should also consider the importance of the cave or specific cave features under your property. You don't want to be known as the person who destroyed a natural, scientific, or cultural treasure.

        If a cave's location is known, how close can I safely clear?

        The actual distance will vary depending upon the size and depth of the cave. The deeper the cave, the farther away you want to be. Although no studies have been made, a 40-50 foot easement on each side of a cave should be sufficient in most cases to protect your interests and the cave.

        A cave crosses my property near the street. I'd like to build on the back of the lot. What is the safest way to put a driveway over the cave?

        By hand. After a path is hand cleared, fill in the low spots with large rocks and a drain pipe if needed. Then bring in gravel to fill in the gaps and level the area. If the cave roof is thick enough this should make a safe driving surface.

        If a stronger surface is needed, a thick, reinforced concrete slab over the cave area will allow for better weight distribution.

        What do I need to know about selling a property with a cave underneath?

        Hawaii State Law requires that the seller disclose all information about the property. That includes any and all information related to a cave underneath.

        A long pole can be inserted horizontally into a small hole at ground level without hitting anything. Could this be part of a larger cave?

        Its probably just a shallow surface feature; but there is no way to be certain. Even if your able explore it completely, there is no way of telling what is underneath. Your best bet is to contact the Hawaii speleological Survey and ask if there are any known caves under your property. (The Hawaii speleological Survey is sub group of the Nation Speleological Society.)

        A cave entrance is on my property. Can I give tours?

        No. Hawaii State law limits cave tour operations to those which existed prior to the passage of the cave law bill.

        I can't build because of a cave; the taxes keep coming; what are my options?

        One option is to donate the property to the Cave Conservancy of Hawaii. The Conservancy is a non-profit organization dedicated to cave preservation. Donations are tax deductible.

        If you can't afford to donate out right, negotiate a partial cash settlement. In the long run, getting some cash and a donation slip out of a bad investment is less expensive than paying taxes forever.

        If the property is over Kazumura Cave, you can also negotiate a cash settlement with the Kazumura Cave Preserve.

        Both the Kazumura Cave Preserve and the Cave Conservancy of Hawaii have limited funds. Cash purchases are made on a first come, first serve basis. If you can reduce the purchase price by making the biggest donation you can afford, it will be greatly appreciated.

        A second option is to use the land for agriculture. Check with the state agricultural department for information about agricultural uses of the land in your area. Its also good to have a plan as to how to sell your product. If you can't sell for a profit, your right back where you started from.

        What are the tax rules for all non-cash charitable donations?

        A taxpayer who donates land, an easement or other personal or real property to a public charity or government agency may generally deduct its full fair market value (less any bargain sale payments), but deductions for donations of "capital gain property" are usually limited to 30 percent of the donor’s adjusted gross income in any given year (10 percent for C corporations), with the remaining value carried forward for up to five additional years."

        If you have a land development question not covered here, or additional information about one of the listed questions, feel free to contact us at preserve@kazumuracave.com.

        The Importance of Cave Preservation


        Caves sit under a wide variety of ecosystems. The environmental health of a cave is dependent upon the health of the ecosystem above it. Cave preservation provides a means to protect natural areas which may otherwise not be preserved.

        Medical Research

        Many isolated micro-environments can exist within a single cave. This means that the potential for finding new organisms is great. Some of these unknown organisms could be useful in curing diseases like cancer or aids. Research is on going.

        Ground Water Testing

        Nearly all caves have a certain amount of water passing through them. The quality of that water is dependent upon the health of the ecosystem above it. Alter the ecosystem and the water quality changes. This makes caves an ideal place to do quality tests before the water reaches the water table.

        Exploration and Discovery

        There are many reasons to enter a cave. Sport cavers do it for the physical challenges. Scientists view caves as natural repositories of knowledge. Surveyors strive to map as much cave as possible. Whatever the reason, without the cave, there's nothing to explore. Everyone therefore benefits from cave preservation.

        What to know before entering a lava tube

        Get permission to enter! - Most cave entrances are on private land so get the land owner's permission to enter. If the land owner says no, then stay out.

        Tell someone responsible where your going!

        Minimum Gear - Hard hat, gloves, multiple lights, long pants, & shoes that cover the whole foot.

        Don't touch! - The walls and ceilings of a lava tube can be covered with fragile lava formations, delicate minerals and biological organisms. Even accidental touching can leave permanent scars.

        Don't Take! - Cave formations belong in caves not on a shelf collecting dust. Leave the cave as you found it. (Also see "Hawaii's Cave Laws" in the reference section.)

        More information related to lava tube caving can be found in "Understanding Lava Tubes and Lava Caves" by Harry Shick.

        How Can I Help Preserve Kazumura Cave?

        There are many ways to preserve a cave. The following are just few possibilities.

        Land Owners

        If you own land above the cave, you can keep the native vegetation intact. This will help preserve the cave ecosystem and has the added benefit of fighting global warming. You might also consider willing your property to the Cave Conservancy of Hawaii to preserve the land after your death.

        If you own an entrance, make sure that anyone entering the cave knows Hawaii's Cave Laws. The easiest way to do this is to place a sign just inside the entrance(s) in a visible spot. You can either make your own sign or contact the Preserve for copies. (To make a sign, just copy the appropriate laws from the Cave Reference section and laminate it. Be sure to print the same information on both sides. That way no one can say, "The sign was blank".)


        Cavers can preserve a cave by leaving the cave as nature made it. Be respectful of the cave. Tread lightly. Remove trash when you see it. Avoid touching anything unless safety requires it. Don't eat in the cave as crumbs can create a bio-hazard. Avoid delicate areas when possible. Its also a good idea to learn how to identify archeological sites so you can avoid them as well.


        Help to unlock the secrets of the cave. This knowledge can generate community support as well as providing a base line for conservation efforts.

        Monetary Support

        Land owners change over time. A lot protected by one land owner, could be developed by the next. For this reason it is important to consolidate the land under one or two entities which are dedicated to preservation.

        In the case of Kazumura, the cave passes under hundreds of lots. If you would like to help preserve this national treasure make a donation.

        At this time online donations can be made through the Cave Conservancy of Hawaii's website. If you would like to donate directly to the Kazumura Cave Preserve, contact us through our email: preserve@kazumuracave.com for information about where to send the check.

        Thanks for your support!