When Volcanoes Ended the World

OlaEight AM, May 18, 1980. A magnitude 5.1 earthquake shakes Washington State, and in seconds

AmaraWow.

Olathe entire north face of Mount St. Helens slides away, the largest debris avalanche in recorded history. Oh, and today is the 46th anniversary.

AmaraKPTV and Fox 4 News both covered it this week. Right,

Ola2.5 cubic kilometers of rock. Rock gone. But here's the thing. That number is actually tiny compared to what we're going to get into today. Okay,

Amaraso get this. We're talking Mount St. Helens as a doorstep. Then we walk all the way up to volcanoes that pumped out four million cubic kilometers of lava! Four million, yeah.

OlaThe Siberian Traps. And according to Wikipedia and the USGS, yeah. The Siberian Traps. And according to Wikipedia and the USGS, that's the event tied to 96% Six per cent of marine species disappearing at the Permian-Triassic boundary.

AmaraThe Great Dying, two hundred and fifty two million years ago, and the lava, plot twist, probably wasn't even the main weapon.

OlaExactly. The gas chemistry is where it gets good. We'll dig into what the science suggests actually drove that cascade.

AmaraAnd then we get to the monitoring question, because St. Helens didn't just kill fifty-seven people. When people (according to the USGS) it completely rewrote how volcanologists watch volcanoes.

OlaSeismometers, GPS deformation sensors, satellite radar-all of it traces back to nineteen eighty. But here's my problem with that story.

AmaraOh, you have a problem-shocking!

OlaThose tools are built for a cone that erupts from a point. A Large Igneous Province is something else entirely. We'll argue that one out.

AmaraAmara's already wrong and we haven't even started. Let's go.

OlaOkay, so picture this—it's Sunday morning, May eighteenth, nineteen eighty, eight thirty-two AM. Someone in Spokane is making coffee. The mountain has been rumbling for two months, sure, but it's Sunday, it's quiet, and nothing has happened yet.

AmaraAnd by the time that coffee's done...

OlaYeah, Spokane goes dark at noon, four hundred kilometers away. Ash everywhere. But we'll get there.

AmaraOkay, so walk me through the warning signs, because this didn't come out of nowhere. Where?

Speaker 3Right; so the USGS and Fox4news both cover this: between March and May seventeenth the mountain had more than ten thousand earthquakes-ten thousand-and the north flank was physically bulging outward at nearly two meters per day.

AmaraWait, per day?

Speaker 3Per day. By May seventeenth the whole north face had displaced about a hundred and thirty meters outward. Steam explosions had been blasting through the summit ice cap since March twenty seventh. Every scientist on site knew the mountain was a loaded gun.

AmaraSo what finally pulled the trigger?

Speaker 3A magnitude five point one earthquake, eight thirty two AM. The North Face just goes. According to the USGS, two point five cubic kilometers of rock slides away, the largest debris avalanche in recorded history.

Amara2.5 cubic kilometers. That's what?

Speaker 3One million Olympic swimming pools travelling at over 160 kilometres per hour. And within 15 minutes. The ash column is already at twenty four kilometres altitude.

AmaraThat is so fast.

Speaker 3And here's the human part, Amara: there was a USGS volcanologist named David Johnston at his monitoring post, about nine kilometres from the summit. He'd actually been warning for weeks that this thing could blow laterally. Nobody fully believed him.

AmaraAnd he stayed.

Speaker 3He stayed. He was covering for a colleague who had a meeting. And at 8:32 he grabbed his radio and his last transmission was "Vancouver! Vancouver, this is it." Then the lateral blast swept him away. His body was never found.

Speaker 4Wow!

Speaker 3Measured: Fifty-seven people died total. According to Fox4news, the eruption flattened two hundred thirty square miles of forest, destroyed two hundred homes and five hundred twenty million tons of ash spread across eleven states. Spokane, four hundred kilometers away, went dark at noon.

Speaker 4At noon.

AmaraOn a Sunday.

Speaker 3Yeah. And the total material ejected was more than 4.2 cubic kilometers.

AmaraOkay, so here's what I keep coming back to: that number, 4.2 cubic kilometers, sounds enormous.

Speaker 3It does. It absolutely does.

AmaraSo why does every geologist I talk to treat Mt. St. Helens like it was almost small? Helens like it was almost small?

Speaker 3Because on the scale of what volcanoes can actually do, it kind of was. So the VEI scale-that's where this gets properly humbling.

AmaraRight. And St. Helens VEI-5-one cubic kilometer of magma equivalent-felt enormous when we were in nineteen eighty.

Speaker 3Okay, so here's the thing: the VEI scale runs to eight, and each step up is roughly ten times the previous one. So VEI-5 to VEI-7 isn't twice as bad.

AmaraIt's a hundred times!

Speaker 3Yeah, Tambora eighteen fifteen. Scene fifteen, VEI-7, around one hundred sixty cubic kilometers of material; Krakatoa eighteen eighty three, VEI-6, roughly twenty five cubic kilometers.

AmaraSo Tambora blows out a hundred sixty times what St. Helens did and most people couldn't name it on a quiz.

Speaker 3The year without a summer, crop failures across the Northern Hemisphere, and it still ranks as a footnote!

AmaraOkay, but wait, you said the VEI goes to You ate? What's at eight?

Speaker 3Yellowstone-tier super volcano stuff. We haven't seen one of those in recorded human history, but even an eight is not what I want to talk about because there's a whole other category.

AmaraUh-oh.

Speaker 3So flood basalts, Large Igneous Provinces, the Siberian Traps.

AmaraOh, you're going to give me the big number.

Speaker 3According to Wikipedia, the Siberian Traps have a volume of around four million. cubic kilometers-4,000,000!

AmaraOkay, I need a comparison. Give me a comparison right now.

Speaker 3I tried my first attempt; imagine four million Mount St. Helens eruptions happening back to back.

AmaraSuper helpful, Ola. Very visceral.

Speaker 3I know, I know. OK, here's better. St. Helens put out one cubic kilometer. The Siberian Traps could bury the entire continental United States under a kilometer of lava. That's the ballpark. Over how long? Wikipedia puts it at roughly two million years of eruptions, spanning the Permian-Triassic boundary around 251.9 million years ago. Right. So not one explosion,

Amarajust Earth bleeding lava for two million years. Continuously—pulses and pauses,

Olabut, yeah; and compare that to the Deccan Traps, sixty six million years ago, sixty six million years ago, around the K-Pg boundary, according to Wikipedia, about five hundred thousand square kilometers covering northwestern India, roughly one million cubic kilometers.

AmaraSo smaller than Siberia but still a thousand times Mount St. Helens.

OlaThe-thousand! And here's where it gets genuinely weird. There's a 2015 study led by a team at UC Berkeley suggesting that Chicxulub impact may have actually accelerated Deccan eruption rates, like the shockwave from the impact triggered more volcanism.

AmaraHold on, so the asteroid hit and then the volcano sped up?

OlaOne hypothesis is that the impact increased permeability in the mantle below the Deccan province. The study suggests those accelerated flows could account for over seventy percent of the total Deccan volume.

AmaraHmm, I mean, I find that... I want to be careful here. That's one model, right?

OlaAgreed, it's contested. The current consensus still puts Chicxulub as the primary driver of the dinosaur extinction. Deccan volcanism probably stressed the ecosystem before and after, but the asteroid is carrying most of the blame for 66 million years ago.

AmaraOkay, but Siberia, 252 million years ago, that one isn't contested. That's your prime suspect for the... They're the biggest extinction ever.

OlaNinety six percent of marine species gone. And here's the thing that haunts me: it wasn't really the lava.

AmaraWhat do you mean it wasn't the lava?

OlaThe lava is just the delivery mechanism. What the traps actually pumped into the atmosphere, the gases, the chemistry, that's where the real killing happened.

AmaraSo four million cubic kilometers of rock is almost like the side effect.

OlaEverything we've been describing is the gun; the bullet is something else entirely. So the lava is basically irrelevant, that's what we said. Now the real question, what actually does the killing?

Speaker 3OK, so here's the nightmare checklist. At 251.9 million years ago, the Siberian Traps start cooking into ancient organic rich sediments. CO2 spikes, temperatures climb, the oceans start losing oxygen, then SO2 and halogens start wrecking the ozone layer and you get acid rain on top of that.

OlaAnd Wikipedia's summary of the Siberian Traps puts the sea surface temperature jump at around 10 degrees Celsius. Ten! For context, we're panicking about two.

Speaker 3Ten degrees? That's not warming, that's a different planet.

OlaRight, and here's the part that actually shocked me. According to research published in Nature Communications, the lava flows themselves weren't even the main gas source. The magma punched sideways underground into the sedimentary rock. You rock cooking it from the inside.

Speaker 3So it's not the eruption; it's what the eruption is baking underground.

OlaSills they're called, horizontal intrusions; those sills hit coal beds, evaporites, organic shales, and the contact metamorphosis just unlocked volumes of CO2 and methane that the magma itself couldn't produce.

Speaker 3Earth basically put a giant stove burner under a fossil fuel deposit

OlaWow.

Speaker 3for two million years.

OlaWhich is why ninety six percent of marine species went extinct, not just killed off, almost completely erased from the record. Sea surface, deep ocean, shallow shelf, all of it.

Speaker 3Okay, so that's the Permian. Clean story, brutal outcome. Now flip it to sixty six million years ago, and I'm going to defend the volcano.

OlaHa ha, here we go.

Speaker 3The Deccan Traps were already erupting when the asteroid hit. Long-term warming of around three degrees Celsius this, driven by Deccan CO2 emissions, is actually documented in the geologic record before the K-Pg boundary.

OlaSure, but compared to what the Siberian Traps pulled off, the Deccan CO2 output at K-Pg was nowhere near the same scale. We're talking a stressed ecosystem versus a dead one.

Speaker 3I'm on both sides a little bit, honestly. But a Dartmouth modeling study suggested the Deccan Traps alone could have been sufficient to trigger the extinction. Extinction! Their estimate was up to 10.4 trillion tons of CO2 over their eruption history.

OlaWait, wait, wait. Could have been sufficient is doing enormous work in that sentence. The Chicxulub ejecta layer shows up globally, simultaneously, right at the extinction horizon. The Deccan was warm slow pressure. The asteroid was a shutdown.

AmaraOkay, but here's a thing that's hard to dismiss. Some studies show that Chicxulub impact may have actually triggered more Deccan eruptions, so the two might not even be separate.

OlaSo the asteroid caused both the impact winter and accelerated

Speaker 5warming?

Olaaccelerated the volcano?

AmaraEarth was having a very bad week.

OlaGenuinely the worst Tuesday-and this is the contrast that matters-the Permian case is actually cleaner than people expect. Still sediment cooking, gas cascade, ninety six percent gone-the K-Pg case is messier because you have two overlapping signals and you can't fully separate them.

AmaraWhich means not every LIP hits the same way. A. It depends what the magma is intruding into.

OlaRight, which raises a question we're going to need in the next part. If the killer is the chemistry cascade, not the visible eruption, could we even see it coming? What would the warning signals actually look like?

AmaraAnd do we have any instruments sensitive enough to catch them?

OlaThat's exactly the uncomfortable answer we're about to dig into. So after all that chemistry chaos, you have to ask, what will we actually see coming?

AmaraRight, and the answer honestly is a lot more than people realize, at least for a cone volcano.

OlaBefore nineteen eighty, monitoring Mount St. Helens meant basic tiltmeters and optical surveying gear. Scientists saw the bulge growing; they did not see the lateral blast coming.

AmaraCentimeter-scale deformation and they still missed the direction of the... of the blast-that is humbling.

OlaFox 4 News covered this for the 46th anniversary. Their piece makes the point that St. Helens essentially forced geologists, seismologists, geochemists, and hydrologists into the same room for the first time. geochemists, and hydrologists into the same room for the first time. Before that, they barely talked to each other.

Speaker 3Nothing like Fifty-seven deaths and 230 square miles of flattened forest to break down disciplinary walls.

OlaTragic but effective; and it drove the creation of the USGS National Volcano Early Warning System. As of the 2018 threat assessment, 161 US volcanoes are now categorized by threat level.

Speaker 3So the tools got much better: continuous GPS networks, InSAR satellites mapping

Olaand ground deformation across entire volcanic fields, broadband Seismometers that can separate magma movement from regular tectonic noise.

AmaraReal-time, Centimeter-scale, Genuinely impressive, and for a Super volcano like Yellowstone, University of Illinois modeling suggests you'd get hundreds to thousands of years of warning, ground uplift on the order of tens to hundreds of meters before anything catastrophic.

OlaOkay, Wait. Hundreds of meters of uplift; that is Not subtle.

AmaraNo, it is not; you would notice.

OlaSo here's what I keep coming back to: those signals work because you're watching a single magma chamber under a defined cone-Yellowstone, Mount St. Helens, Taupo-there's a thing to point your instruments at.

AmaraAnd a Large Igneous Province is not that thing.

OlaExactly; the Siberian Traps were not a cone. They were a continental plumbing system bleeding lava across millions of square kilometers over two million years.

AmaraSo the question is not just whether our tools are sensitive enough, it's whether they're pointed at the right shape of disaster.

OlaHmm, the monitoring framework we built from nineteen eighty assumes a point source, a single throat.

AmaraYeah, and a LIP has no throat. The kill signal we described last segment, that CO2 and methane cascade. Cascade cooking up through sediment seals-where do you even put the seismometer? So here's the thing: we spent four segments building the case against a threat our instruments can't actually see. Right, and that's the mismatch. Fox4news covered the Mount St. Helens legacy this week, noting the eruption fundamentally changed how scientists monitor volcanic activity. But that framework is still built around a single throat, a single cone.

OlaA Large Igneous Province has neither. It's flood basalt across an area larger than Europe, intermittent pulses over millions of years. There's no spike on a seismometer, the signal is diffuse.

AmaraAnd the kill mechanism is chemical: CO2, SO2, fluorine, chlorine released across millennia. We could detect unusual gas flux changes with modern atmospheric sensors, sure.

OlaBut here's what gets me, Ola: at what point does it stop reading as a volcano? The volcanic emergency and just look like climate change.

AmaraThat's exactly it. The Siberian Traps didn't announce themselves; they just started.

OlaSo Amara says the tools we have are still real progress. Satellite gas monitoring, global seismic networks, cross disciplinary response, not nothing.

AmaraAnd I'd say we optimized for the wrong shape. Shape?--we build instruments for Mount St. Helens-the Permian-Triassic boundary didn't care about our instruments.

OlaNo, it didn't.

AmaraThe Siberian Traps did not announce themselves; they just started. So, we went from one Sunday morning in Spokane-coffee on the counter; mountain's been quiet for two months-to earth bleeding lava for two million years. That is a journey.

OlaI mean the Siberian Traps buried us alive in slow motion; no bang, no transmission, nobody sending a last radio call-just relentless.

AmaraAnd that's kind of the whole episode, right? David Johnston got six miles from the mountain and stopped. And still had no warning-imagine the eruption that has no edge at all.

OlaRight; every instrument we built after nineteen eighty is aimed at the wrong kind of volcano.

AmaraThat's the fault line," pun intended.

OlaOh, we're doing puns now?

AmaraWe earned it. Okay, Amara, hit 'em.

OlaIf this one cracked something for you, subscribe and leave us a review. Got a theory you think we got wrong? Email us at hello@heyMatto.com.

AmaraWe genuinely read those. Thanks for spending your Sunday with us.

OlaSmiling, see you at the next fault line.