By Jonny Lupsha, News Writer

A U.S. Army soldier survived a 70-foot drop into Kilauea at Hawaii Volcanoes National Park, according to Hawaii News Now. After crossing a safety rail to get a better look at the volcano rim, the ground gave way under him and he fell to a ledge below. Hawaii’s volcanic features range from awe-inspiring to deadly.

The 32-year-old soldier visiting Kilauea was saved by a narrow rock ledge, the Hawaii News Now article said. Had the ledge not formed in that precise location, he would have fallen to his death 300 feet below on the caldera Halema’uma’u. This death-defying incident and the circumstances surrounding it prove that Hawaii’s chain of volcanoes is a complex geological marvel that extends far beyond hollow mountaintops and lava.

Volcanoes, Local Rainfall, and Poisonous Gases

Just like any other mountains, temperatures dip near the summits of volcanoes. In fact, one of the largest volcanoes on Hawaii’s Big Island is called Mauna Kea, which means “White Mountain.” It gets its name from the snow that sometimes falls at its peak—yes, even Hawaii sees a bit of snow on its mountains. But how do the volcanoes affect rainfall?

“The trade winds blow from the northeast here most of the time, bringing air that’s become humid, saturated with water over thousands of miles of travel across the Pacific,” Ford Cochran, Director of Programming for National Geographic Expeditions, said. “The volcanoes deflect air up and around the island, and as the rising air cools, clouds condense and it begins to rain.” Cochran refers to Hilo, a city on the Big Island’s eastern side, as a “lush garden” with “lots of overcast and rainy days.” On the leeward side of the island, however, drier air blows down the mountaintop and heats up, resulting in severely reduced rainfall.

Furthermore, southwest of Kilauea, the Ka’u Desert stretches onward, also due to the volcano, but for different reasons. “A paucity of rainfall isn’t what keeps this particular desert a desert,” Cochran said. “Sulfur dioxide gas emerging from the caldera reacts with oxygen and moisture in the atmosphere to create tiny suspended droplets of sulfuric acid.” This volcanic fog is appropriately called “vog.” Falling into Kilauea may be a preferable end compared to breathing in this deadly gas.

Life-Saving Volcanic Eruptions—No, Really

Underneath Yellowstone National Park, a thick but sparse continental crust—which is largely composed of silicon, aluminum, and potassium—separates the park from a geological hot spot. There’s another hot spot far beneath the Hawaiian Islands as well, but unlike Yellowstone, the crust between Hawaii and its hot spot is a thinner, denser crust called oceanic crust. “Compared with continental crust, it has less silica and more resembles the chemistry of rocks in the upper mantle,” Cochran said. “Magma composed of liquid silica has Velcro-like properties—it forms long chains and sticks to itself; this makes silica-rich magmas sticky, viscous, and highly explosive.” On the other hand, Hawaii’s oceanic crust is comprised largely of minerals that come from iron, magnesium, calcium, and sodium.

Why does the chemical composition of the crust matter? In Hawaii, the lava forms a dark rock called basalt. “Though the basalts formed by some of Hawaii’s lava flows are dense and massive, bubbles generated by the release of gases from the magma or explosive interactions with water sometimes transform lava into frothy pumice or cavity-filled forms called scoria and vesicular basalt,” Cochran said. These hole-filled formations cool much more quickly than they would if they were formed from a less porous substance. Most crucially, he said, this is why there are no geysers on Hawaii, nor do the islands explode. “If Hawaii were like Yellowstone, entire islands might blow themselves to bits once in a while.”

The Big Island’s widely contrasting precipitation and local climates dazzle the imagination even as Kilauea’s poisonous vog creeps along a local desert. Dense crusts and porous basalts let off enough steam to prevent the islands from exploding. The soldier who fell into Kilauea had a near-death experience that was prevented by its inner rim. These fickle geological wonders can be both perilous and beneficial, often simultaneously. For now, locals seem to be in Mother Nature’s good graces.

Ford Cochran contributed to this article. Mr. Cochran is Director of Programming for National Geographic Expeditions. As an undergraduate at the College of William and Mary, he studied English literature. He then took graduate courses in Earth Science at Harvard University and earned a Master of Philosophy degree in Geology at Yale University.