This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
The eruption on Kilauea volcano has settled into a routine, with one fissure pumping lava in a fiery river that runs to the sea, creating new land. It's a pattern that has repeated on the Hawaiian islands for millions of years. Unfortunately, there's another pattern repeating: people seeing a rather calm and perfectly ordinary volcano doing what shield volcanoes do, and thinking the entire island's about to blow. An eye-rolling number of doomsday predictions have been made since the eruption shifted to the Leilani Estates/Vacationland area.
I regret to inform you: none of them are true. Not even a little bit.
Okay, actually, I don't regret informing you. I actually love debunking myths. It's just that so many people seem so very attached to their myths: they come up over and over and over again. The poor volcanologists working the USGS Volcanoes Facebook page are having to shoot down rumor after rumor, most of which have already been repeatedly debunked.
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So here, I have gathered some of the most persistent myths, and the posts that busted them, so you can join the Kilauea Eruption Debunk Brigade. Truth isn't always stranger or more exciting than fiction, but it's important when it comes to real-world events!
Myth: Kilauea will explode, destroying the entire island of Hawaii – just like Krakatoa!!!!
I regret to inform you that Kilauea is not going to put on that kind of show. It can't. Kilauea and Krakatoa are completely different types of volcanoes that have completely different types of lava, and therefore their eruptions are nowhere close to being the same.
One reason that Kilauea and Krakatoa are so different in their explosiveness is silica. Krakatoa, which last erupted in 2017, is a stratovolcano, with tall, steep sides made of ash and lava. Its magma is relatively high in silica, which is also what makes it so explosive. The high silica concentration means the magma is more viscous, or resistant to flow — so any gases it contains struggle to expand. But the change in pressure when the magma reaches Earth’s surface means the gases can suddenly expand — and they do, explosively.
Kilauea, by contrast, is a shield volcano: Its magma is relatively low in silica and flows easily, oozing out in characteristic ropy flows called pahoehoe and thick, blocky flows called aa. Kilauea’s magma tends to be lower in gas concentrations, as well, and what gas there is finds it easier to escape, so that less pressure builds up within the magma. As a result, the volcano is far less explosive.
Myth: The Hilna Slump will catastrophically slide into the ocean, and a megatsunami will destroy everything!!!
I regret to inform you that this myth has been debunked by the scientist who originally investigated the Hilna Slump, giving rise to the idea of gigantic landslides causing major disasters. Since not all of you have Facebook and therefore not be able to see it without creating an account, I'll go ahead and reproduce it here:
I fear I am one of the scientists responsible for the panic about megatsunamis from Mauna Loa. Years ago, for an open house at the School of Ocean & Earth Science at UH Mānoa, I prepared a detailed map of the Hawaiian Islands showing topography and bathymetry (depth of the ocean) with superimposed dots showing earthquakes. My interest was the earthquakes and the tsunamis they cause, but most visitors were staggered by the map and asked "Why have you been hiding those landslides from us?"
So when National Geographic asked if I could help them with a TV documentary on tsunamis I figured it was a good way to tell everybody about the giant landslides of Hawaiʻi. The video is attached.
https://www.youtube.com/watch?v=RWbBiVxLzSsBut that video was made way back in 2005--before youtube! Since then a small group of us have been all over the islands mapping and sampling deposits left by megatsunamis from giant Mauna Loa landslides. In particular, we have dated half a dozen of the landslides radiometrically (using uranium-series dates of coral the tsunamis left on Lānaʻi) and find that each one occurred right at the very end of an ice age, when sea level was low but when Earth was going through a rapid climate change from cool-dry to warm-wet conditions (giant landslides others have studied in the Society Islands show the same timing).
That timing makes sense. If sea level is several hundred feet lower then now, then there is significantly less buoyancy to help to hold up the mountain. If the climate is changing rapidly then you suddenly turn on tropical storms, with the possibility of loading the slopes with huge amounts of rain. If, at the same time, a volcano is inflating prior to eruption and thereby making its slopes steeper, then *that* is the moment the slope is maximally unstable and most likely to let go.
The last time those conditions all coincided was 20,000 years ago, and, sure enough, the last giant landslide we know of was one of Mauna Loa's Ka Lae slides, which was about 18,000 years ago. If the mountain stays true to form, we should not expect another giant landslide for 40,000 years or more.
Of course, if the slopes get really steep or you have an exceptionally violent earthquake, then you might get a landslide at an unexpected time. But that's where HVO's monitoring of Mauna Loa comes in. Not only does HVO monitor earthquakes beneath Mauna Loa, they also monitor ground deformation down at the millimeter level using continuously-recording GPS. Those data tell us that the Kona slope of Mauna Loa remains absolutely static. It looks for all the world like the western flank of Mauna Loa is nailed to the underlying sea floor, meaning that any large earthquakes or expansion of the mountain will occur to the southeast rather than to the west. The southeast side has much gentler slopes than the west and even the Great Kaʻu Earthquake of 1868 (magnitude close to 8), which occurred beneath the SE slope, was not enough to shake it loose despite ground accelerations significantly exceeding one "g" (rocks were thrown from the ground). So, while there will be more giant landslides, it really does not look like there is one in our near future.
So, no, the flank of Kilauea isn't going anywhere in a hurry.
Myth: Kilauea will trigger all of the Cascades volcanoes/Ring of Fire!!! The world is about to end!!!!!
I regret to inform you that Kilauea is completely separate from the Cascade Range, let alone other volcanoes in the Ring of Fire. It won't be triggering a major eruption along that volcanic chain.
“There is absolutely no linkage between the Hawaiian chain and the Cascade Range, and the geological environment is completely different,” said Kent, who has spent much of his career analyzing Northwest volcanoes. “Eruptions in the Cascades have nothing to do with any potential eruption of Kilauea volcano. However, having said that – any time you live in a region of volcanoes, you should be vigilant. At some point, the Cascade volcanoes will erupt again, and it may even occur in our lifetimes.”
Also, too:
The phrase “Ring of Fire” is evocative, but that is about as far as it goes. Geologically speaking, the “Ring of Fire” isn’t anything more than a coincidence of volcanoes and earthquakes. The supposed ring doesn’t even encircle the whole Pacific Ocean; sometimes it includes locations beyond the Pacific, such as Indonesia . Underneath all these regions, large tectonic plates interact as they move on the Earth’s mantle. But the volcanoes and earthquakes in the “Ring of Fire” are not directly linked, so when eruptions or earthquakes occur simultaneously in Japan and Chile, it’s not because they are triggering each other. In fact, there is very little evidence that earthquakes or other volcanoes can cause a volcano to erupt.
Okay? So. Remember that when one of the spectacularly active volcanoes along the Pacific Rim goes ahead and erupts, because you just know that when one inevitably does, whether Kilauea's done with the Lower East Rift Zone or not, everybody's favorite conspiracy-gobbling aunt/uncle/cousin/coworker/etc. will be claiming that it's all Kilauea's fault. It is most certainly not.
Myth: There are more volcanoes erupting now than ever before!!! IT'S THE END OF THE WORLD!!!!!!!!
I regret to inform you that volcanoes are erupting at about the same rates as they have done for centuries upon centuries. It's just that we have awesome things like satellites and television and the internet and social media, so we're more aware of them than we've ever been before.
Thus, all major trends in our recent volcanological record can be reasonably explained by historical events, technological changes, and exploration influences. The apparent increase in activity reflects increases in people living near volcanoes to observe eruptions and improvements in communication technologies to report those eruptions. The best evidence that these trends are apparent rather than real comes from the record of large eruptions, whose effects are far reaching and less likely to escape documentation even in remote areas. Their constancy over the past two centuries is a better indicator of the global frequency of eruptions than the improved reporting of smaller eruptions.
The eruption is exciting enough without doomsday scenarios. So, y'know, sorry-not-sorry about raining on these rumors. And remember: if it sounds too disaster movie to be true, it's probably a myth!