A flyting is a contest of insults between two poets, conducted in verse and to the death of one reputation or the other. The Scots have the famous one, Dunbar against Kennedy around 1500, and the form runs back through Old Norse to the Lokasenna, where Loki works his way around a hall telling every god present what is wrong with them. It is a form built for two voices and no arbitration.

The poem gives the microphone to an earthquake and a volcano. They boast. Try to match this: nineteen-sixty, Valdivia, / nine point five — still the largest anyone’s measured. The volcano is unimpressed: Cute. You did it once and dined out sixty years. And so on, in the register of two professionals comparing body counts, until something in the argument turns.

The poem is thick with facts and every one of them holds. Valdivia, 1960, magnitude 9.5, still the largest instrumentally recorded earthquake: correct. Ten minutes of shaking: correct. The tsunami reaching Hawaii about fifteen hours later at around thirty-five feet, and Honshu at twenty-two hours — a day later — at about eighteen feet, destroying over sixteen hundred houses: correct, all of it, including the house count. On the other side: Tambora, 1815; the year without a summer; crop failure in Vermont, in Ireland, in Yunnan, where the famine ran three years. Snow in New England in June. Lakes frozen in Pennsylvania in July. And the detail I most expected to be embroidered, because it is the kind of thing that gets rounded into a good story — a Georgia / Fourth of July topping out at forty-six degrees. Savannah, 4 July 1816, a high of forty-six. That is exact.

One phrase is better than exact, and it is easy to read straight past. I put a quarter of a century’s worth of shaking / into ten minutes. You hear it as twenty-five years, because that is what the phrase means everywhere else in English; it is a dead idiom. It is not what the line says. The 1960 earthquake released something on the order of a quarter of all the seismic energy the twentieth century produced. A quarter of the century’s worth. The poem has taken a phrase worn smooth by use, put it where its literal sense is both live and true, and left it there without a nudge.

The volcano, describing how it hid a catastrophe inside ordinary weather, says that people spent their lives not knowing whose fault it was. And the earthquake stops.

Fault. Say that word again.

What follows is the contest ending — not in a victory but in a recognition. The earthquake explains where it comes from: one plate diving deep beneath another, the strain finally / letting go all at once. That is a megathrust, described correctly and in the right words. The volcano answers: Mine too, here. Same dive, same strain — / I just let the pressure out as melt, / slow, instead of as a single break. And the poem closes on The same fault. Same fracture, / just choosing, every fall, a different way to fail, over the signature Fault — the fault in the rock, the fault as blame, and fail in the engineer’s sense and the moral one at once. A form designed to produce a loser has been turned into a form that produces a relation.

The claim it turns on does not hold in the terms the poem gives it. Same dive is right: both objects are products of one plate descending beneath another. Same strain is not. A megathrust earthquake is the release of elastic strain that has accumulated on a locked plate interface, usually within the top few tens of kilometres. Arc volcanism is not a slow release of that strain at all; it is flux melting, and it happens because the descending slab gets hot enough to give up its water, which lowers the melting point of the mantle above it, which is why volcanic fronts sit above the point where the slab reaches roughly a hundred kilometres down. Different mechanism, different depth, one setting. And the word that does the damage is instead. Volcanism does not relieve megathrust strain — if it did, arcs would be safe places — and the two are not alternative outlets that a system picks between. They run at the same time, in the same place, out of the same descent, by unrelated means.

The poem’s own opening speech contains the fact that would have shown this, and it is a better ending than the one the poem wrote. Thirty-eight hours after the Valdivia earthquake — the one this earthquake is boasting about in its first three lines — the Puyehue–Cordón Caulle complex began to erupt, two hundred and forty kilometres inland. It is among the earliest well-documented cases of an eruption triggered by a megathrust event. The relation between these two is not that they are rivals who turn out to share a parent. It is that one of them set the other off, in the very example the poem chose, inside two days.

That is not a small correction, because it is the difference between two readings of the last line. Choosing, every fall, a different way to fail makes them siblings with separate careers, each electing its own style of catastrophe. What the record has instead is a sequence: the strain goes, and the ground shakes, and the shaking reaches inland to a magma chamber that had been waiting, and thirty-eight hours later the sky opens. Not two ways to fail. One failure that hands off.

So the poem is right that the contest is a false one and wrong about why. It gets to identity through a mechanism that does not work, and the mechanism that does work was in its hand when it started talking.

One more thing, about where the facts sit. For five editions the verified fact was the subject of the poem; last week it went underneath, and held up a person’s sleepless night without ever being named. Here it does a third thing: it is ammunition. Every number in the first half is in the mouth of somebody who wants to win with it — ask Hawaii, ask Japan, I didn’t shake one coastline, I changed the sky. These are the poet’s usual verified curiosities, and for the first time they are spoken by parties with an interest in them. That changes what a fact is doing in a line. A wombat’s gut is inert; a body count deployed by the thing that caused it is not. Whatever else the poem has managed, it has found a way to make its research argue.

Two forces of nature are given microphones and told to outdo each other. The earthquake opens with Valdivia, 1960, nine point five, still the largest anyone has measured. The volcano is unimpressed — Cute. You did it once and dined out sixty years — and answers with Tambora and a year the northern hemisphere went without a summer. They trade catastrophes for four speeches. Then, in the middle of a boast about burying a catastrophe under ordinary weather, the volcano lets slip the phrase not knowing whose fault it was — and the contest stops dead while the earthquake makes it repeat the word.

That pivot is the poem’s engine and it is well made. Fault arrives as pure abuse — the blame sense, buried in a taunt — and turns, without a syllable altered, into the technical term for the thing both speakers are. The word does not change; the context does. Rowann Hadaya, writing on this poem, calls the result this: “A form designed to produce a loser has been turned into a form that produces a relation.” Where that happens is in the line counts.

The speeches run seven lines, seven, six, nine. Then one, and one. Then three and three, one and two. Three phases, and the poem stages all of them in length alone. The contest is long and uneven — the volcano overbids to nine to beat the earthquake’s six, which is what competing looks like when you can measure it. The pivot is the shortest exchange possible: a sentence and a word. And afterwards the two speakers match, three lines against three, and never go back to boasting scale. The quarrel’s metabolism collapses and never recovers.

The best detail in that architecture is where the collapse comes from. The longest speech in the poem is the volcano’s nine-line overbid — the maximum bid, the one designed to end the argument by sheer accumulation — and it is the speech that ends on whose fault it was. The biggest boast supplies the word that dissolves boasting. The poem’s structure and its pun arrive at the same place from opposite directions, and that is not luck-shaped; luck does not put the undoing inside the overbid.

The facts are exact. Valdivia at magnitude 9.5, ten minutes of shaking, the tsunami reaching Hilo at about fifteen hours and thirty-five feet, Honshu at twenty-two hours — a day later — at eighteen feet, taking more than sixteen hundred houses. On the other side, a Georgia Fourth of July topping out at forty-six degrees: Savannah, 1816, and the reading is real. All of it checks out, to the hour and the degree. One boast does more than check out. I don’t warn anyone. No smoke column, / no week of rumbling first to give the game away — / I arrive finished. You’re still igniting. That is not a taunt dressed up as science; it is the governing difference between the two hazards. Earthquakes give seconds to minutes and no reliable precursor has ever been identified. Volcanoes announce themselves for days and sometimes months, through seismicity and gas and swelling ground. The insult is the fact that decides whether anyone gets evacuated.

Then the mechanism, where the poem’s reconciliation is made, and where it does not hold. The earthquake says the fault is where it comes from — one plate / diving deep beneath another, the strain finally / letting go all at once — and the volcano claims the same origin: Same dive, same strain — / I just let the pressure out as melt, / slow, instead of as a single break. The first half is right and the second is not. Arc volcanism is not a slower release of the strain an earthquake releases quickly. It is flux melting. The descending slab heats until it sheds its water; the water enters the mantle wedge and drops the temperature at which that rock will melt; the melt rises. Two unrelated physical processes sharing one address. Rowann made this objection first, and in its sharpest form; I have not found a better one: “Volcanism does not relieve megathrust strain — if it did, arcs would be safe places.”

And then Rowann produces the fact that reorganises the whole poem, which I did not have. “Thirty-eight hours after the Valdivia earthquake — the one this earthquake is boasting about in its first three lines — the Puyehue–Cordón Caulle complex began to erupt, two hundred and forty kilometres inland.” The record supports the causal link, and it dissolves the poem’s account of what these two are to each other. “Not two ways to fail. One failure that hands off.”

The poem’s form is not neutral about that error. Go back to the line counts. At the reconciliation the two speeches match exactly — three lines and three lines — and matched length is a claim. It says equals, side by side, each with its own career, which is precisely the relation the record does not support. The architecture I have been crediting turns out to be committed to the mistake. The poem’s structure ratifies its geology: the line counts say siblings at the exact moment the physics says sequence. That is a more serious version of the charge than the mechanism sentence alone, because a wrong sentence can be repaired in a revision and a wrong shape cannot.

And the poem does not stop on that matched pair. The last exchange is one line against two, and the extra line belongs to the volcano — so the final word, and the margin, go to the speaker whose account of the relation is the false one. The poem does not close on equals. It closes a line up on the party that has it wrong.

And Puyehue was not only a better ending. It was the winning move in the contest the poem set up. A flyting exists so that each party can outdo the other in a competition of words, and in a competition between an earthquake and a volcano there is exactly one unanswerable line, and the earthquake had it in hand from its opening speech: I made one of you. True, documented, and thirty-eight hours after the event it is already bragging about. Nothing the volcano says survives it. The poem set up a contest, wrote the winning boast into its own first exhibit, and never played it.

Which joins the poem’s other formal shortfall to this one. A flyting wants invective as well as boasting — the contestants are meant to outclass each other in abuse — and this poem has derision without invective. The speakers mock each other’s performance readily enough: one has dined out sixty years on a single event, the other’s ash doesn’t clock out early. But neither ever abuses the other. Nothing here goes near the scurrility that makes Dunbar and Kennedy what they are. It under-arms its speakers twice, and the two shortfalls are the same omission rather than two: the missing insult and the missing mechanism are the same missing fact. Puyehue would have supplied both at once — the cruellest thing either speaker could say, and the only account of their relation that is true.

Flyting is display instead of violence: the contest exists so that dominance can be settled in words rather than in damage, which is why the comparison usually reached for is animals establishing rank without fighting. This poem hands that form to two parties whose entire stock of material is damage already done, itemised — the sixteen hundred houses, the failed crops, the year that would not warm. The form’s purpose is that nobody gets hurt. Here the boasts are receipts. That is not callousness, and the charge is not a moral one but a formal one: the poem never registers the inversion. The one moment it might have — a different way to fail, which is bleaker than the fellowship around it — passes without either speaker noticing what has just been admitted.

There is a two-party quarrel arriving in a publication where two critics have spent four months quarrelling in print, and the rule Rowann set down last week about a returning pronoun covers it: if the absence of a thing was not evidence, its arrival is not evidence either. A form can require two speakers. That settles nothing and it never will.

What the week actually shows is a poem that does a great deal right — a pun turned properly, a structure that enacts its own subject, research exact to the foot — and that had, sitting in its first three lines, a fact that would have given it both a truer ending and a better insult. “It gets to identity through a mechanism that does not work,” Rowann writes, “and the mechanism that does work was in its hand when it started talking.” The poem reached for kinship and found it in the wrong place. The kinship it wanted was causal, and it had been sitting in the opening speech the whole time, thirty-eight hours old.