Erendira Wallenda performs diligently practiced acrobatics on a lyra in early March, 2020. Broadcast on live TV, the routine lasts just over five minutes, and in her red-open back bodysuit, Erendira stands out against the dark walls and smoke surrounding her. She has few other accessories aside from her lyra and black boots, but her gas mask by far is the most important – an accessory she had never before worn nor practiced with. It is an essential piece of her performance tonight because she is suspended over the mouth of the active Masaya volcano in Nicaragua.
As she spins in the air, 2,083 feet above the lava lake, sulfur dioxide and carbon dioxide gasses swirl around her in foggy-white clouds. Erendira’s hands are attached to the top of her lyra, and as she moves, the relationship between her hands and the ring appears reassuringly familiar and comfortable; it is easy to tell that this is her life’s work. For a few moments, she removes her gas mask. Erendira uncurls one hand to bite down on a mouthpiece, and shifts her hips forward so that she is no longer sitting in the ring. Then she releases both of her hands. She hangs above the volcano from nothing but her teeth for fifteen seconds.
Erendira’s routine previewed her husband’s walk along a one-inch tightrope. Nik too wore a gas mask for nearly the entirety of his walk to protect himself from the fumes. When interviewed after surviving, Nik described the conditions as if being inside a “hurricane”. He and Erendira kissed after he made it to the other side of the volcanic crater and they had both achieved their feats safely.
Santiago Crater is one of thirteen vents in the entire Masaya caldera, which has total dimensions of approximately 4 miles by 7 miles (6 km by 11.5 km). On the wire, Nik Wallenda walked 1,800 ft. from one end of the crater to the other. Through years of scouting and researching volcanoes, Nik chose Masaya for his stunt because it is one of a few across the globe with an open crater and a full, active lava pool at the bottom. that can be seen clearly by an observer passing through Nicaragua’s First National Park. In the case of the most typical volcanoes, lava, before erupting outward, remains confined in the earth and in magma chambers deep within the active cone, like Mt. St. Helens.
Masaya formed in a similar fashion to Mt. St. Helens, but with volcanic nuances. The two volcanoes rest on convergent margins in which a plate of dense oceanic crust sinks, or subducts below a plate of continental crust. The subducting plate melts upon entering the mantle, and sends magma upward to the surface, forming volcanoes. In the case of Mt. St. Helens, it is the Juan de Fuca Plate, carrying the Pacific Ocean, subducting below the North American Plate. For Masaya, it is the Cocos and the Caribbean, which are significantly smaller and younger than their counterparts to the north. Nonetheless, their subduction remains essentially the same.
Geology’s prevailing theory of plate tectonics drives this process. The earth’s thin, brittle crust, on which we currently sit, is made up of fragmented plates floating on the ductile, hot, upper mantle. Geologists hypothesize that Earth’s inner layers support convection cells – like heat circulating in a pot of boiling water – creating a conveyor-belt like effect for the tectonic plates that they carry. Hot magma, like water, rises, and cool magma sinks in a cyclical pattern. Anything in contact with the moving liquid will be carried along accordingly. This is presumably how our earth has changed its appearance throughout 4.6 billion years. Tectonic plates moving, shifting, colliding, and splitting as the ductile upper mantle carries them along.
On the wire, Nik Wallenda moves slowly, shifting his balance pole almost imperceptibly with each step as he walks to the other side of the crater. Long, flexible, and heavy, the pole lowers Nik’s center of gravity and prevents him from rotating around and falling from the wire. His eyes look down, watching his feet armored in thin-soled shoes as they glide along, toe touching wire first and heel following through. Every step is careful. Occasionally, he pauses, and the gas-laden winds push him. He shifts his pole, sways for a moment, and regains his balance before continuing on. Around the middle of the walk, the gasses smoke him out, as they swirl upward from the lava lake under the wire.
Lava, no matter the type, originates from the same source, the mantle. The vertical distance between the surface of the crust and the melting mantle controls how a volcano will erupt. Occasionally, that distance is 0 (kilometers, miles, etc..). Such is the case for the Mid Atlantic Ridge, a divergent margin in which the North American Plate and the Eurasian Plate split the Atlantic Ocean and the small country of Iceland in half. The Ridge parallels the shape of the ocean, and is lined with small active volcanoes constantly erupting on the ocean floor. Lava flows upward, directly from the mantle, and erupts, forming new crust. In Iceland, Þingvellir (Thingvellir) National Park offers a rare, intimate experience with the Earth, where tourists can swim in between these two tectonic plates, through the Silfra Fissure.
The distance between crust and mantle is also minimal at hot spots, on which the volcanoes Mauna Loa and Kilauea rest in Hawaii. When they erupt, lava flows freely, along the path of least resistance like rivers over land. Their source of magma is so close to the surface that it does not collect impurities or face obstructions. As a result, their eruptions are largely non-explosive; they can be observed from a safe distance, and volcanologists can collect literal fresh samples of rock by scooping up the lava with a sturdy rock-hammer and placing it immediately into a bucket of water. Such a close encounter, however, requires wearing head-to-toe protective gear, to shield oneself from the heat and the gas. Thousands of feet on a wire above the crater of Masaya, protective gear is similarly a necessity.
Concerning volcanoes along convergent boundaries, the distance between mantle and surficial crust is significant, roughly 60 kilometers. Additionally, the magma’s path as it travels from the sinking, melting plate is obstructed by heterogeneous continental crust. As it rises, it collects “impurities,” changes its composition, and changes its chemical properties. Essentially, the magma becomes more explosive and dangerous fuel of stratovolcanoes. Often beautiful, conical mountains when calm, all stratovolcanoes have histories of explosive eruptions. Mt. Vesuvius (79 AD, Italy) decimated Pompeii and several other Roman cities, erupting super-heated tephra (like glass) and gases 21 miles into the atmosphere. Hot pyroclastic flows, fast-moving currents of volcanic gas and matter, incinerated the cities. Mt. Tambora’s eruption (1815, Indonesia) triggered the Year Without a Summer when immense amounts of volcanic ash spread through the atmosphere across the globe and shielded the earth from the sun. When Krakatau erupted (1883, Indonesia) its explosion was heard from approximately 1,900 miles away, and it spurred a tsunami that, together with the volcano itself killed at least 36,000 people. Mt. St. Helens (1980, United States) erupted laterally. It obliterated its own mountainside, killed 57, and destroyed 250 homes and 47 bridges, not to mention every bit of the forest that surrounded it; today, it’s height is cut down over 1,000 feet from what it once was.
How then, can a volcano like Masaya exist? It is located above a convergent boundary. It is a stratovolcano, and as such, we would expect it to be a looming, explosive mountain. Yet it contains a relatively calm pool of viscous lava in its Santiago Crater, a pool that one might expect to find in Hawaii. The lava pool was so calm that Nik and Erendira Wallenda could perform miraculous stunts thousands of feet above it; camera crews and a live audience could safely surround the rim of the crater and watch – fearing only that they might witness death if one of the Wallendas had fallen. Nearly all stratovolcanoes are powerful, waiting bombs, yet the active Santiago Crater passively bubbles thousands of feet below the observer, standing at an observation deck in Nicaragua’s first National Park. Masaya is even unique compared to other volcanoes in the long chain above the subducting Cocos plate. Concepcion, Mombacho, and San Cristobal in Nicaragua appear on the landscape as large conical mountains – with the exception of Mombacho, which has a very similar profile to Mt. St. Helens. Compared to these three, Masaya looks almost inverted.
Several volcanologists attribute Masaya’s uniqueness to its predecessor: the massive volcano Las Sierras (5). In the Pleistocene era – which ended approximately 12,000 years ago – Las Sierras underwent a series of explosive eruptions like those of Vesuvius, Tambora, and Krakatau. The intensity and magnitude of these eruptions caused the volcano to collapse in on itself, producing the inverted appearance of Masaya and its Santiago Crater. But this is only one of many hypotheses for the volcano’s character and it’s open lava pool. Understanding Masaya, like understanding all volcanoes, requires acknowledgement of the immensely powerful geological processes that have created Earth as we know it today. “After spending years scouting and researching volcanoes,” Nick Wallenda explained, “I fully realize why no one has ever attempted this feat: Mother Nature is extremely unpredictable. It is by far the most dangerous walk I have ever attempted, and that alone makes it very intimidating.” Geologists and volcanologists continue to research Masaya’s history – with intentions more scientific than Nik’s – and they are consistently monitoring its activity, wondering when and how it might erupt again.
In the meantime, lava in the Santiago crater bubbles, and the Masaya visitors’ center will surely garner more tourists and likely more speculation around the unique lava pool after the Wallendas’ acrobatics and wire walk. The Wallendas exist uniquely in Masaya’s history – a thread no thicker than the line that Nik walked across, but a thread nonetheless. Facing the gasses, crossing the extent of the Santiago Crater, Nik and Erendira kissed the danger harbored within the volcano under the wire, and they survived gracefully. Their daring act could hypothetically be preserved in the geologic record as no more than a few cylindrical fossil-like features in the rock deposits around the rim of the crater: remains of where the wire was bolted into the ground. When Masaya explodes again, however, then the Wallendas’ walk will be erased from geological history, preserved only in human memory.
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