The Galapagos Islands: Inside a lava tunnel on Santa Cruz

Pristine beach on Santa Cruz, Galapagos.Credit: Shutterstock

There are few places in the world that can lay claim to the title "heaven and hell" on Earth, and this volcanic archipelago about 970 kilometres off the coast of South America in the Pacific Ocean is one of those rare places.

We fly into the island of Baltra, which is the gateway into the Galapagos. Its dusty brown land with metre-tall cacti is a world away from the Andean foothills surrounding Quito, Ecuador's capital, from where we made our connecting flight.

Our Intrepid Travel guide, Jacinto, greets our small group of travellers ahead of our eight-day sailing trip around the Galapagos' famed southern islands, Santa Cruz, Floreana, Espanola and San Cristobol. We're a young group – all aged between 25 and 35 – and not the usual age group, as we soon discover when we cross paths with a group of Baby Boomers who exclaim, "enjoy your school trip".

A lava tube in the highlands of Santa Cruz, Galapagos National Park.Credit: Shutterstock

We make our way through the highlands of Santa Cruz, stopping at the scalesia cloud forest for a short trek through the scrublands. Tourism is the main industry for the islands, which are home to a large number of endemic species, and are most famous as the place Charles Darwin conceived his theory of evolution.

Jacinto stops and points to the surrounding green vegetation, "not edible" he says. The two words are repeated several times during our trek, which leads us to wonder how any type of life survives on the island. The Ecuadorians, who took the islands from Spanish ownership in 1832, tried for hundreds of years to farm the land, with minimal success. They also discovered that very little native vegetation was safe for humans to eat. "Farmers have tried but the land here is not suitable for agriculture," Jacinto says, explaining the geology of volcanic rocks, which are most commonly found at plate boundaries and cover about 8 per cent of the Earth's surface.

We make our way around to the entrance to a large dark cave, descend a steep pile of unsteady rocks and enter one of the islands' many lava tunnels. "This one is extinct. It has been dead for many hundreds of years," Jacinto says, pointing to the arched walls of the tunnel.

Trekking the highlands of Santa Cruz with guide Jacinto.Credit: Annie Dang

"There are many lava tunnels like this, new ones, being formed and unearthed by big and small volcanic eruptions on the island." There's an abundance of lava tunnels, a labyrinth of complex and connecting underground tubes, such as the one we've climbed into, on the other 17 islands and three smaller islands in the Galapagos archipelago. Some of the best lava tunnels, however, can be seen on Santa Cruz.

The abundanceof lava tunnels found across the Galapagos Islands, which cover 7880 square kilometres of land across 45,000 sq km of ocean, is because the archipelago sits on a tectonic plate – the Nazca plate – which is moving south and under the South American plate, at a reported rate of about 6.5 centimetres ayear. The archipelago is also located on one of Earth's hotspots (or "hell' spots), a gap in Earth's crust where mantle plumes rise to create volcanoes. There are more than 40 hotspots on Earth and one of the most well-known is the chain of Hawaiian Islands, which in 2018 saw the formation of Loihi, the newest Hawaiian volcano, created during an eruption of Kilauea Volcano.

It's my first time standing in the belly of a lava tunnel. The air is silent and cool, and the sunlight is glaring through at both ends. Smooth black rocks cover the five-metre archway stained brown and red through years of erosion. As we speak, our voices echo and circulate through the dark space through which the Earth's fiery core once roared – red, steaming lava pushing violently through the walls of the tunnel and bursting through the Earth's surface, creating long caves and lava tunnels, and sometimes creating new islands.

Rocky decent: Inside a lava tunnel on Santa Cruz.Credit: Annie Dang

The first of the Galapagos Islands were formed some eight million years ago, with some scientists claiming it could have been formed up to 90 million years ago. The youngest islands, Isabela and Fernandina, are still being formed. Last year Sierra Negra – one of five volcanoes on Isabela, which is one of the most active islands in the archipelago – erupted for the first time in 13 years. A reminder to the world and travellers that the Galapagos Islands are more than just a fascinating microcosm of life and evolution – they are a dynamic microcosm of the planet's geology where hot lava can rise up through the cracks and unleash hell on Earth.

TRIP NOTES

Annie Dang travelled as a guest of Intrepid Travel.

Santa Cruz, the second largest island in Galapagos, is home to some of the best extinct lava tunnels.Credit: Shutterstock

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traveller.com.au/galapagos-islands

intrepidtravel.com

FLY

United Airlines flies direct from Sydney to Houston, with a connecting flight into Quito. See united.com

TOUR

Galapagos Island Hopping on-board the Daphne is an eight-day itinerary. Priced from $2495 a person, the tour includes a local guide, meals, snorkelling and land excursions. Wetsuit hire and entrance to Galapagos National Park is an additional charge. Intrepid offers a range Galapagos Island tours. See intrepidtravel.com/au/galapagos-islands