Hector, meet Hawaii.
As you’ve probably heard by now, a fairly powerful hurricane is moving westwards across the Pacific Ocean, and it could – somewhat unusually for the state – make landfall on Hawaii’s Big Island in the next few days. It could also just brush past it. It’s currently a Category 4, which means that it has wind speeds of 209-250 kilometers (130-156 miles) per hour.
The appearance of a powerful hurricane anywhere there are humans obviously isn’t welcome, and floods and dangerous wind conditions are possibilities. What several people have been asking on various social media channels, though, is what happens when a hurricane meets an erupting volcano?
Sorry to disappoint fans of histrionic tabloids, but it’s not going to cause anything apocalyptic. The two events will barely interact, if at all, and here’s why.
For the last few months, the Kilauea eruption has been generally without incident, with the notable exception of that near-fatal, lava-bomb-meets-tour-boat drama that played out a few weeks back.
The summit crater continues to slump as magma beneath it continues to drain. At the same time, fissure 8 in the Lower East Rift Zone (LERZ) has remained the sole lava-producing fissure.
There’s a chance that the magmatic source is temporarily running low. The latest United States Geological Survey (USGS) updates on the situation note dropping lava flux rates from fissure 8. The lava channel is crusting over, and less lava is entering the ocean these days, with laze levels diminishing overall.
The USGS stress, however, that “it is common for eruptions to wax and wane or pause completely,” adding that “a return to high levels of lava discharge or new outbreaks in the area of active fissures could occur at any time.”
Still, what you currently have is a fair bit of lava going on, with some vog and laze. So how can that dance with a hurricane?
Volcanoes release a lot of energy in various ways. Effusive, lava-producing eruptions like this one aren’t that powerful compared to, say, the explosive cataclysms produced by stratovolcanoes, because the latter releases more energy per second – that’s power – than the former.
The May 1980 eruption of Mount St. Helens unleashed at least 100,000 trillion joules of energy in moments, which is certainly a lot. Here’s the thing, though: Hurricanes can release around 603 trillion joules every single second, most of which goes into cloud and rain formation, not wind generation.
Trust me, you couldn’t nuke a hurricane into not existing. So forget Kilauea – even the most powerful explosive eruption finding itself in the middle of a hurricane would be like a firecracker going off in a massive bonfire.
Could the heat from the lava add some thermal fuel to the warm water that powers the hurricane though? Hypothetically, sure, perhaps a very small amount, but there’s no evidence to show this has any effect.
A 2014 study – which observed Hurricane Iselle suck up some ash from a Hawaiian eruption – found that it promoted the separation of positively and negatively charged particles in the cloud layer. This led to an increase in volcanic lightning, which is neat.
Will the hurricane itself have much of an effect on the eruption? The rain may cause faster cooling of fresh lava, and there’s a chance that heavy rainfall will cause poorly consolidated slopes of volcanic sediment to slump and collapse – but that’s nothing major.
Researchers also told The Smithsonian back in 2014 that, although the lower air pressure over an active volcano could hypothetically encourage more lava to erupt forth, magma reservoirs are too deep underground to be affected. The air pressure change involved during a hurricane would be too small anyway. Don't expect a new eruption triggered by the hurricane, then.
Update: Yellowstone Volcano Observatory’s Scientist-In-Charge and a senior volcanologist at the USGS, Dr Michael Poland, is nonplussed. There’ll be “pretty much no impact,” he told IFLScience. The rain could quench some lava, but he points to similar clashes in the past where the eruption was entirely unaffected.
He also refers to the 2014 clash mentioned above, noting that at the time, lava was advancing on the town of Pahoa. “Of course, the hurricane had no impact whatsoever on the flow, nor the eruption itself.”
Sorry, Internet: this isn’t the titanic mash up you may think it is.