The Power of Volcanoes: How Lava Tubes are formed and where to see them on the Big Island

Lava Tubes – Shaping and Transforming the Earth From Within

Although the often-churning lava lake in Kilauea’s caldera and rivers of lava flowing down the slopes of Mauna Loa grab our attention, volcanic activity underground is equally awe-inspiring. During every significant eruptive event in the illustrious history of Kilauea and Mauna Loa (the most active and largest volcano in the world, respectively), lava tubes form under the Earth’s surface, leaving networks of caverns behind after the lava has stopped flowing. As rivers of lava flow out from the erupting volcanic crater or rift zone at an astonishing 2,000+ degrees Fahrenheit, the outer “casing” of the lava channel gradually thickens, enveloping the inner molten flow. Much like a garden hose, the hardened outer shell allows the fluid inside (in this case, lava rather than water) to flow quickly and smoothly. Already blazing lava becomes even hotter and fully entrapped underground. When the eruption eventually subsides, the inner stream of lava drains out, leaving a massive cave, or lava tube, behind.

Nahuku-Thurston Lava Tube – A Volcanic Wonder Right Next Door

One of the world’s best-preserved lava tubes is a centerpiece of Hawaii Volcanoes National Park and is only 5 miles away from your rainforest accommodations at our Volcano bed and breakfast. Named after Lorrin Thurston, who discovered the lava tube in 1913 and played a pivotal role in establishing the park, the Nahuku-Thurston Lava Tube is one of the most-visited sites on the Big Island. After a quarter-mile approach hike winding through the dense, fern-covered forest (keep an ear and eye out for the distinctive bird call of the Apapane and the bright yellow plumage of the Amakihi, among other native Hawaiian birds you may encounter along the way), you’ll cross a bridge and enter the enclosed lava tube. The underground portion is 400 yards long, with the cavern wide and tall enough to be welcoming even for young kids and those with claustrophobia. As you walk through, you’ll get a visceral experience of the overwhelming power of lava, having carved out such a massive path through the Earth’s core some 500 years ago. After the lava tube’s environment cooled off following that eruption centuries ago, unique microbes, plant life, and insects made their home within the damp and isolated cave-like ecosystem, which still thrives today. Like the rest of the park, the Thurston Lava Tube is open 24 hours a day, so head over after dark to avoid the daytime crowds. The interior of the lava tube has ambient lighting from 8 am until 8 pm, so if you decide to visit during off-peak hours, be sure to bring a flashlight or at least the light from your phone. It is often wetter and cooler in the lava tube than above ground, so wear an extra layer, and because the footing can be damp or uneven in places, closed-toe shoes are better than sandals. If you want to keep exploring after you exit the lava tube, do a portion of the Kilauea Iki Trail, which starts just steps away and has some of the park’s most stunning volcanic terrain and viewpoints.

Other Big Island Lava Tubes Near Volcano

In a somewhat unlikely location right in the center of Hilo, Kaumana Caves State Park offers another opportunity to venture down into a lava tube (this one formed by Mauna Loa rather than Kilauea). More rugged than Thurston and without lighting (make sure to bring a flashlight), the Kaumana network of caves is more adventurous, extending up to 2 miles. Once you descend the stairway, two different pathways diverge, one leading left and the other right. Each side features different lava tube scenery, including areas where the sun shines through an overhead opening in the ceiling, creating an oasis of sunlight amidst the darkness. With unpredictable footing and lots of moisture within these lava tubes, wear sturdy hiking boots and a rain jacket. Restrooms are available near the cavern entrance as well as picnic tables, so grab lunch from the Hilo Farmers Market before heading over to the caves, and finish the day with a visit to Rainbow Falls, which is just down the way on the same street (Kaumana Drive). If Thurston has you thirsting for even more underground exploration, the Kazumura Cave Tours will take you deeper into the wild world of Kilauea’s lava tubes. At over 40 miles long and flowing from the high-elevation flank of Kilauea down to sea level, Kazumura is the world’s lengthiest continuous lava tube. The easiest of the three offered tours is the Lava Falls Tour, which costs $50 per person and goes for almost a mile on the 2-hour expedition. You’ll be in constrained spaces and climbing down ladders, so it’s only suited for people comfortable in tight underground areas. But you’ll be rewarded with rare lava spires and natural lava tube formations preserved for ages. Gloves, rope, knee pads, and hard hats are required (and provided), and the tours are limited to those aged 11 years and older. Guided tours are available Monday through Saturday, with reservations by phone only (808-967-7208). Stay with us at our Volcano bed and breakfast and explore the unique lava tubes of the Big Island!