Obviously, an erupting volcano can kill you in several direct ways — typically via heat and/or explosive force. But there are some rare and weird ways to die near a volcano. Did you know that a volcano can make your head explode? Or melt your face with hydrochloric acid?
Here are 10 totally insane ways to die via volcano.
1) Poisonous gas. Two people were killed near Mount Kilauea in 2000, their lungs swollen and their skin eaten away by hydrochloric acid. Effusive volcanoes, which may seem safe due to the leisurely way lava flows out of them down to the sea, create some of the deadliest volcanic hazards (maybe because they lull people into a false sense of security). When lava reaches the sea, the chloride in the sea salt and the hydrogen in the water react and form hydrochloric acid. As the water flashes into steam, it carries a cloud of acid with it. Sudden shifts in the wind can unexpectedly push this cloud directly onto unwary onlookers. This toxic cloud, by the way, is known as lava haze, or laze.
2) Flying shrapnel. When lava meets the sea, the lava is cooled very quickly. The cooling contracts the lava, and the sudden stresses can cause chunks of it to be flung into the air. These chunks, called tephra, can fly quite far, be surprisingly large — and do a significant amount of damage if they hit you.
3) Falling into scalding seawater. Where lava flows into the sea, the water gets pretty hot. The temperature of lava is over 2,000 degrees F. The cooled lava forms shards and lumps, piled unevenly along the shore. New lava flows over this, forming a seemingly solid top layer. Unfortunately, this whole arrangement, known as a lava bench, is very unstable. When it collapses, anyone standing on top of it will likely fall into scalding hot sea water.
4) Downhill bike rides. It seems like a pretty fun idea – take a bus up to the rim of a volcano, then ride a bike down a paved road back to the bottom. Roaring downhill on a bike with a volcano as the backdrop sounds awesome, but it's also really dangerous. Tourists who did this (few of whom were experienced bicyclists) wiped out, crashed into rocks, or went into oncoming traffic when this practice was allowed. The problem got so bad that after multiple accidents and fatalities the National Park Service banned commercial bike tours in Haleakala National Park.
5) Exploding your head. What's inside your skull? Your brain. What's your brain full of? Water. What happens to water when you instantly superheat it? It turns to steam. What happens to a volume of water when it turns to steam? It expands. Rapidly. Violently. So when a pyroclastic flow, a stream of gas and particulates than can reach temperatures above 1,000 degrees F, covers your town, it's going to look a lot like outtakes from Scanners. Which is exactly what happened to the residents of Herculaneum in 79 CE.
6) Scalding waves. Remember those collapsing lava benches? Well, you don't actually have to be on the bench when it collapses to die. If you're nearby, you might be deluged by the scalding hot waves that the collapse kicks up.
7) Vog. All the noxious gases and particulate matter kicked into the air by volcanoes can mix together and form volcanic smog, or vog. Vog doesn't kill you right away, but inhaling particulates and sulfur fumes over the long term can cause lung problems and make things very rough on people with asthma and other pre-existing conditions. Worse, particulates in the air amplify other pollution problems, increasing acid rain and further exacerbating respiratory problems.
8) Falling into a lava tube. Those effusive volcanoes are real bastards. At least with explosive volcanoes you know what you're in for. Effusive volcanoes send lava to the sea via lava tubes. The surface layer cools and hardens while lava flows beneath. That surface can be thin and unstable. What looks like a safe place to walk on can quickly crack open to the lava below, creating what's known as a skylight. Falling into lava, that would be bad. But even if the tube is dormant, you're still falling a good distance onto rock. A woman once broke both legs falling into a lava tube at Kilauea National Park.
9) Suffocation. One of the most subtle ways a volcano can kill is also the most devastating. Under certain conditions, volcanic activity at the bottom of a deep lake can infuse the lake with a huge amount of CO2. Cold lakes often have stratified temperature layers. Tremors or other factors can cause the lake to "turn over." This releases the CO2 very suddenly. Because it is extremely cold and dense, it can flow down geographic features, hugging the ground. Anyone caught in the cloud will find themselves with no oxygen to breathe. In 1986 this exact scenario played out at Lake Nyos in Cameroon. A cubic kilometer of CO2 was released. It flowed into a nearby village and killed more than 1,700 people.
10) Tephra jets. If you only take one thing away from this article, it's this: stay the hell away from lava benches. Because even if a collapsing bench doesn't drop you into scalding sea water, douse you with scalding waves, or open a hole into an active lava tube, it might just send a scalding hot geyser of steam, liberally spiked with tiny globules of fiery lava and large, glassy chunks of tephra bursting up in your face.
PBS. "Casefile: Herculaneum Uncovered."
Pratt, Sara E. "Danger in paradise: The hidden hazards of volcano geotourism." Earth, March 19, 2012.
U.S. Geological Survey. "Viewing Lava Safely - Common Sense is Not Enough."
U.S. Geological Survey. "Volcanic Lakes and Gas Releases."
Images: U.S. Geological Survey.