Study 06 Explosion vs Earthquake

Study 06 — Explosion vs Earthquake: shape against a point track

An announced explosion is a point in space-time — one mountain, depth zero, one catalog instant published to 10 milliseconds — and from that point a deterministic ladder of arrivals travels outward through the crust: Pn first, then Pg, then Sn, then the slow Lg train. Every rung of the ladder is computable before any waveform is opened. The explosion must ride its ladder. An earthquake sheared onto the same point track floods the windows the track says should stay starved.

One correction to the obvious framing, made up front because the sealed Form depends on it: the clock is not external to the waveform. ComCat origin times — for the six announced DPRK tests exactly as for earthquakes — are seismically determined, fitted from the waveform by the catalog agency; no listed archive carries a pre-detonation announced time for any test. What is external is the point track (one epicenter, depth 0, zero free parameters) and the analyst class label. The discriminant is therefore confinement shape given a catalog clock, not clock externality — and the ±30 s clock-jitter control runs on both classes symmetrically.

This study extends the shear method validated by the eclipse study (Study 1) — a frozen exact-integer law, an adversary that mimics magnitude but not shape, predictions sealed before the event — from the sky to the ground. See Eclipse 2026 — Overview for the sealed method and Eclipse 2026 — Model shear for what happened when a magnitude-mimic met a shape test.

Note

Sourcing convention, carried over from Study 1: VERIFIED means fetched live from the named service on 2026-07-16 by this program; REPORTED means taken from the published literature or contemporaneous agency statements at abstract/press level, not independently re-derived. Both are marked inline throughout.

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The forcing and its clock

The forcing is a zero-free-parameter point track under a fixed catalog clock: USGS-NEIC ComCat origin times for the announced explosion-class events — waveform-fitted like every catalog time (see the clock note below), but pinned to a track with nothing left to fit.

• The clock. All six announced DPRK nuclear tests carry seismically-determined ComCat origin times published to 10 ms — e.g. 2017-09-03T03:30:01.760Z for the sixth test (event class us2000aert, 41.3324N 129.0297E, depth 0; VERIFIED via live fdsnws-event query). ComCat quarry and mine blasts (eventtype='quarry blast', reviewed status) carry 10 ms clocks of the same kind. All of these clocks are waveform-fitted by the catalog analyst — none is external. What is external for the explosion classes is the analyst label and, for the DPRK tests, the fixed point track; the clock circularity is the same on both sides, so the ±30 s jitter control applies to positives and negatives alike.
• The track. A POINT track with zero free parameters: fixed epicenter (Punggye-ri, ~41.30N 129.08E, depth 0 in all six USGS solutions — VERIFIED) plus the catalog clock. From the point, per-station epicentral distance Δ gives a deterministic regional arrival ladder:
  • Pn onset at Δ / 7.9–8.1 km/s
  • Pg at Δ / 6.0 km/s
  • Sn at Δ / 4.6 km/s
  • Lg group window from Δ / 3.6 to Δ / 3.2 km/s
• The stations. IC.MDJ (Mudanjiang, 44.618N 129.593E, Δ ≈ 370 km — coordinates VERIFIED via fdsnws-station) and IU.INCN (Incheon, Δ ≈ 470 km — waveform retrieval VERIFIED for the 2017 test window only; the INCN 00.BHZ station epoch was closed 2012-10-16 → 2013-11-21, so INCN has no data for the 2013-02-12 test — availability VERIFIED).
• Clock precision vs window width. Predicted arrival windows at regional distance are good to ~1–2 s (velocity-model limited), so window edges are padded ±2 s. The discriminant rides inside windows tens of seconds long; against those, a 10 ms clock is effectively noise-free forcing.

The three-dimensional picture: a single fixed point at the surface of the crust, an instant fixed by the catalog before any window is cut, and cones of compressional and shear energy expanding through known rock at known speeds toward fixed stations. Every window is cut before any waveform is opened. That is the whole track. Nothing is fitted by this program — the only fitted quantity, the catalog clock, is inherited from the agency and jitter-controlled on both classes.

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The response archive

Raw, public, integer-native, no authentication. Every claim below was exercised end-to-end on 2026-07-16.

Archive	Exact access	Format	Cadence	Auth
EarthScope (IRIS DMC) FDSN dataselect — raw waveforms	https://service.iris.edu/fdsnws/dataselect/1/query?net=IU&sta=INCN&loc=00&cha=BHZ&starttime=2017-09-03T03:30:00&endtime=2017-09-03T03:40:00	miniSEED (STEIM-compressed integer counts — natively integer, no float ingestion needed)	Continuous archive, seconds-to-URL for any historical window; near-real-time for current data	None for open networks (IC, IU are OPEN — availability service confirms restriction=OPEN). service.iris.edu 307-redirects to service.earthscope.org; use curl -L.
USGS ComCat FDSN event service — ground-truth catalog with analyst event-type labels	https://earthquake.usgs.gov/fdsnws/event/1/query?format=text&starttime=2017-09-03&endtime=2017-09-04&minmagnitude=5&latitude=41.3&longitude=129.0&maxradiuskm=300	text / geojson / QuakeML; geojson carries a type field (earthquake, quarry blast, explosion, nuclear explosion, and related labels)	Static for historical events; minutes-latency for new events	None
FDSN web services specification registry — protocol reference + other data centers	https://www.fdsn.org/webservices/	Specification pages: fdsnws-dataselect v1.1 (miniSEED), fdsnws-event v1.2 (QuakeML), data-center registry	Static reference	None

End-to-end verification record (2026-07-16)

• Waveforms: fetched 36,864 bytes of real miniSEED (IU.INCN 00.BHZ) spanning the 2017 DPRK test in one URL. Companion services verified: fdsnws-station (channel epochs + instrument responses for IC.MDJ back to 1996-11-09) and fdsnws-availability (IC.MDJ 00.BHZ OPEN, 1999 → 2026-07-15, covering all six tests; location code 60 at 40 sps since 2016). IC.MDJ 00.BHZ open miniSEED spans 1999-05-18 → present, plus a 1996–1999 no-location-code epoch — one station covering every test.
• Catalog: all six DPRK tests returned with exact origin times, plus the 2017 post-test collapse and the ambiguous 2017-09-23 / 2017-10-12 near-site events. eventtype='quarry blast' queries verified (e.g. nc73854040, M2.6, 2023-03-07T21:50:38.300Z, type:'quarry blast', status reviewed) — an effectively unlimited label-only ground-truth corpus of industrial blasts: the analyst class label is external, but the 10 ms clocks are waveform-fitted like earthquake clocks, so any test using those clocks inherits the same circularity (jitter control required there too).
• Registry: confirms the same query grammar works at any registered FDSN center (NCEDC, SCEDC for quarry-blast-dense California networks) if EarthScope lacks a channel.

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The adversary

The adversary here is two-sided, and both sides are real events, not simulations.

Side (a): shallow small earthquakes at the test site itself. On 2017-09-23 at 08:29:16.810 UTC, an ml 3.6 event occurred at Punggye-ri, depth 5 km (VERIFIED in ComCat). The China Earthquake Administration announced a "suspected explosion" — then reversed to non-nuclear. USGS stated it could not conclusively confirm natural vs man-made. CTBTO called it "unlikely man-made", collapse-like (REPORTED, contemporaneous agency statements). Three weeks later, 2017-10-12 at 16:41:08.670 UTC, an mb_lg 2.9 at depth 5 km from the same relaxation sequence (VERIFIED). These are tectonic-class radiation from within ~2 km of the shot points — same path, same site, same geology as every positive.

Side (b): ripple-fired industrial blasts. Real chemical explosions at depth ~0 — but detonated as second-scale delay-fired sub-charges. The smeared source time function injects spurious spectral modulation that pushes scalar P/S discriminants earthquake-ward. ComCat's reviewed quarry blast corpus (e.g. nc73854040, VERIFIED) supplies thousands of them.

And one event mimics both classes at once: the 2017-09-03T03:38:31.810Z ml 4.1 cavity collapse, 8 min 30 s after test 6 (VERIFIED) — explosion-adjacent location and clock, earthquake-like radiation.

Why the mimicry works on magnitude-rulers. All of these share the scalar fingerprints classical rulers measure: shallow depth, similar mb, emergent regional codas. A shallow low-magnitude earthquake produces weak surface waves, so its mb/Ms goes explosion-like — the published failure mode. A ripple-fired blast produces Rg and spectral banding that drags P/S scalars the other way. Any single number can be faked.

Why shape defeats it — the shear. The shape test never asks "what is the scalar amplitude ratio of this waveform in isolation." It asks: does energy sit confined inside the arrival ladder predicted from a FIXED catalog clock and a POINT depth-0 track? An announced explosion has zero free parameters — clock fixed, epicenter known, depth 0, compressional-first everywhere — so integer energy must land inside the predicted Pn/Pg windows while the Sn/Lg windows stay starved. An earthquake's clock is fitted the same way (both classes' clocks are catalog products — which is why the jitter control runs on both sides), but it radiates shear with directivity (the Lg and Sn windows flood), and it sits at nonzero depth. A ripple-fired blast violates confinement in time: its source function is seconds long, so P-window energy leaks past the point-source window edge. The mimic can fake any single scalar; it cannot fake confinement to a point track it does not share. This is the same shear geometry that separated the superstorm from the eclipse in Eclipse 2026 — Model shear: magnitude copied, shape betrayed.

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The blind spots this study targets

Four documented failures of the existing toolkit, each one a place where a scalar ruler broke and shape was never asked.

1. The flagship ruler failed at small magnitude. mb/Ms — the classical teleseismic discriminant — is reported to have shown poor discrimination for the DPRK tests, starting with the 2006 mb 4.3 event, too small for reliable Ms measurement at teleseismic distance. The field's move to regional P/Lg ratios is documented in the Sandia/OSTI study "Discrimination of Seismic Events (2006–2020) in North Korea Using P/Lg Amplitude Ratios" (Tibi, Seismol. Res. Lett. 2021; osti.gov/biblio/1781542) — but the fetched abstract discusses only the P/Lg discriminant and the 2019/2020 mb 3.6–3.8 events, not the mb/Ms failure. (REPORTED — the mb/Ms failure is standard-literature motivation, not stated in the fetched abstract; not independently re-derived)

2. The best regional ruler admits it does not transport. Kitov & Rozhkov (arXiv:1712.01819) achieve Mahalanobis D² > 100 above 4 Hz — yet state their results "cannot be directly extrapolated to the population of tectonic earthquakes in the same area." (VERIFIED from fetched abstract) P/S discrimination degrades below ~2 Hz and is path-dependent: thresholds trained on one region do not travel. A discriminant demonstrated only against aftershocks has never met the open population.

3. Below the floor, the experts disagree with each other. The 2010-05-12 micro-event (Lg magnitude 1.44 per Zhang & Wen 2015), located within ~2 km of the 2009 test site, has been classified oppositely by expert groups across a decade: Zhang & Wen 2015 said "explosion"; Ford & Walter and Kim et al. (BSSA 2017, Lamont) said "earthquake/no-test"; a 2024 reexamination (Earthq. Res. Adv.) again argues explosion. Below roughly mL 2 the published toolkit yields no consensus verdict at all. (REPORTED)

4. The confusion runs live, in both directions. CEA called the 2017-09-23 tectonic/collapse event a "suspected explosion" before reversing; USGS "cannot conclusively confirm" its type. Conversely, ripple-fired mine blasts are routinely flagged earthquake-ward by scalar discriminants — which is why ComCat carries a dedicated analyst "quarry blast" label rather than an automated one. (REPORTED, contemporaneous agency statements)

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The shear metric

Same three-part construction as Study 1: a confinement integer, a traveling-lag signature, exact integers end-to-end, threshold frozen on history then sealed.

Confinement analog — energy inside the predicted window

From the catalog clock and the point track, cut fixed windows on the raw integer counts: [Pn_pred − 2 s, Pn_pred + 8 s] for P, and the Lg group window [Δ/3.6, Δ/3.2 km/s]. miniSEED is STEIM integer natively — no float ever enters. The confinement integer is the ratio of summed squared counts (exact big-int) P-window : Lg-window, after the sealed integer-coefficient difference high-pass filter: a 4th-order first-difference cascade, coefficients (1, −1) applied four times — and because a fixed difference operator's response moves with sample rate, the Form seals both per-sample-rate variants (20 sps and 40 sps) verbatim. The emphasized band above ~4 Hz at 40 sps is the band where Kitov & Rozhkov report D² > 100.

• Explosion → P-confined (ratio large).
• Earthquake → Lg-flooded (ratio small).
• Collapse → both windows starved of high-frequency P.

This is the seismic twin of the eclipse study's confinement discriminant: energy stays inside the predicted window, or the event is not the announced class.

Traveling-lag analog — riding the ladder

The catalog clock plus the point track predicts absolute onset times at every station with zero parameters fitted by this program. Measure the integer sample-index lag between predicted Pn onset and the observed onset in the raw counts — per station, per phase — using an exact integer STA/LTA detector whose parameters are sealed Form fields: short and long window lengths in samples, trigger threshold expressed as a shift comparison (STA·2^a > LTA·2^b), and first-crossing tie-break (earliest sample index wins). An announced explosion rides the ladder: lags ≈ 0 within model error, coherent across stations and phases. An earthquake sheared onto the point track shears: its P and Lg lags disagree across (station × phase), because its depth and phase geometry do not fit a depth-0 ladder. Both classes' clocks are catalog-fitted, so the ±30 s jitter control runs on both classes — demonstrating that the lag profile, not clock provenance, does the separating. The lag profile across (station × phase) is the traveling signature.

Integer quantization

Exact integers end-to-end, per program law:

• Raw miniSEED counts are integers.
• Window energies are exact big-int sums of squared counts.
• The confinement discriminant is the 1/64-bit quantized log2 of the P:Lg energy ratio, computed exactly with no division and no floats: the bucket index is the unique integer m with (ΣLg²)⁶⁴ · 2^m ≤ (ΣP²)⁶⁴ < (ΣLg²)⁶⁴ · 2^(m+1) — exact big-int powers, shifts, and comparisons only.
• Lags are integer sample indices at the native 20/40 sps.
• Instrument-response epochs (IC.MDJ responses changed 2013-05-05 and 2016-04-12 — VERIFIED via fdsnws-station) never enter the metric, because both windows of a ratio come from the same record.

Threshold derivation plan — derive on history, freeze, then face the future

• Positives: the six announced DPRK tests at IC.MDJ 00.BHZ (single station covering 2006–2017 continuously — availability VERIFIED) and IU.INCN (five of six tests — INCN was offline 2012-10-16 → 2013-11-21 and has no data for the 2013-02-12 test; availability VERIFIED).
• Negatives: the 2017-09-03 collapse, the 2017-09-23 and 2017-10-12 near-site events, plus matched-magnitude regional earthquakes from ComCat within 500 km, selected by an exact query sealed verbatim into the Form (magnitude type, tolerance, depth ceiling, time span — no post-hoc selection freedom).
• Adversary-direction check: the ComCat quarry blast corpus, scored under the per-region annex Form (see S2 — the sealed IC.MDJ/IU.INCN stations cannot observe California-scale blasts).
• Threshold: the integer bucket boundary maximizing separation on positives-vs-near-site-negatives only, sealed into the Form before evaluation on the wider earthquake population and before the ambiguous 2010-05-12 event — which is scored, never trained on. Because this boundary is optimized on the same nine events, the in-sample fit is not itself evidence; the gate is S1's leave-one-event-out protocol below.

Warning

Clock circularity is symmetric, and the Form must say so. Origin times for both classes — announced tests and earthquakes alike — are fitted from the waveform by the catalog agency, so feeding any catalog origin time to the ladder is partially circular. The control therefore uses deliberately perturbed clocks (±30 s jitter) on both classes, and this control is stated inside the sealed Form itself.

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Historical corpus

Positives — six announced tests, one mountain, one rising ladder of magnitude

All origin times and coordinates VERIFIED by live USGS ComCat fdsnws-event fetch, 2026-07-16. All depth 0.

Date (UTC)	Clock (UTC)	Event	Response	Source
2006-10-09	01:35:28.020	DPRK test 1 (announced) — Punggye-ri	mb 4.3, 41.294N 129.094E; smallest in corpus	VERIFIED: ComCat usp000eurb; yield class REPORTED (sub-kiloton to ~1–2 kt range per literature estimates)
2009-05-25	00:54:43.120	DPRK test 2 (announced)	mb 4.7, 41.303N 129.037E	VERIFIED: ComCat; regional analysis REPORTED: Geophys. J. Int. 180:243 (2010)
2013-02-12	02:57:51.490	DPRK test 3 (announced)	mb 5.1, 41.299N 129.004E	VERIFIED: ComCat
2016-01-06	01:30:01.480	DPRK test 4 (announced, "H-bomb" claim)	mb 5.1, 41.2996N 129.0467E	VERIFIED: ComCat; REPORTED: Geophys. J. Int. 206:1487 (2016)
2016-09-09	00:30:01.440	DPRK test 5 (announced)	mb 5.3, 41.2869N 129.0783E	VERIFIED: ComCat us10006n8a
2017-09-03	03:30:01.760	DPRK test 6 (announced, thermonuclear)	mb 6.3, 41.3324N 129.0297E; yield 250 kt (NORSAR; JGR Solid Earth 2019: 250 kt, bounds 148–328 kt) — an order of magnitude above all prior tests	VERIFIED: ComCat; yield REPORTED: NORSAR + AGU JGR 2019

Negatives and adversaries — the mimics, recorded raw

Date (UTC)	Clock (UTC)	Event	Why adversarial	Source
2017-09-03	03:38:31.810	Post-test cavity collapse, ml 4.1, depth 0 — 8 min 30 s after test 6	Explosion-adjacent location AND clock, earthquake-like radiation; CTBTO characterized the class as "collapse"	VERIFIED: ComCat
2017-09-23	08:29:16.810	Punggye-ri ml 3.6, depth 5 km	CEA announced "suspected explosion", then reversed; USGS could not conclusively confirm type; CTBTO: "unlikely man-made". A live institutional misclassification at the exact test site — the sharpest available negative	VERIFIED: ComCat (parameters); REPORTED: CEA reversal via CNBC/NPR 2017-09-23
2017-10-12	16:41:08.670	Punggye-ri mb_lg 2.9, depth 5 km	Post-test relaxation sequence (Lamont-Doherty: the bomb "set off later earthquakes"); tectonic-class radiation within ~2 km of the shot points, sharing path and site with all positives — defeats any discriminant that secretly learned path geology	VERIFIED: ComCat
2010-05-12	per Zhang & Wen 2015 (waveform-fitted → jittered like earthquake clocks)	Contested micro-event near the 2009 site, Lg magnitude 1.44 (Zhang & Wen 2015)	The standing stalemate: "explosion" (2015), "earthquake" (BSSA 2017), "explosion" again (2024 reexamination). Ground truth unresolved — defines the floor below which no published method separates the classes	REPORTED: literature citations, not directly fetched
2023-03-07	21:50:38.300	California quarry blast nc73854040, M2.6, reviewed	Representative of the ripple-fired corpus: a true chemical explosion whose delay-fired source function violates the point-in-time assumption; thousands of reviewed labels available for the confusion-direction test	VERIFIED: ComCat geojson type:'quarry blast'

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Pre-registration

Target

A sealed integer confinement threshold plus arrival-ladder window definition — station list, phase velocities, window offsets, exact filter, onset detector, 1/64-bit bucket boundary — that classifies any future announced explosion-class event entering ComCat (the next DPRK test; no eventtype-labeled blast within the standing-law radius has been verified to exist, so no fallback class is claimed) explosion-side at IC.MDJ/IU.INCN using only the catalog clock and raw counts — and that classifies fresh shallow regional earthquakes earthquake-side. The 2010-05-12 contested event is pre-registered as a scored holdout with its verdict published either way; before it is scored, its usable waveforms at the sealed stations must be verified present in the FDSN archive.

Cadence — standing law, event-driven

• Re-verify the sealed Form against every new ComCat event within 300 km of 41.3N 129.0E above mb_lg 2.5.
• Monthly, re-verify against a deterministic draw of 10 fresh reviewed quarry blast events + 10 matched shallow-earthquake events from ComCat, scored under the per-region annex Form (the sealed IC.MDJ/IU.INCN stations cannot observe California-scale blasts). The draw is sealed: seed derived deterministically from the month string, ComCat query URL sealed verbatim, and the matching rule (magnitude type, tolerance, depth ceiling, distance band) sealed alongside — any re-runner draws the same events.
• Each pass re-fetches raw miniSEED from the FDSN archive and re-proves from disk. No cached verdicts.

The standing-law Form

Sealed into the program's invariant ledger with the same seal/re-verify machinery Study 1 uses. Drift in any field = refuse.

{
  sealed_at:    <required ISO8601 seal timestamp — S3 is not live until this field exists>,
  stations:     [IC.MDJ.00.BHZ, IU.INCN.00.BHZ],
  track:        point(41.30N, 129.08E, depth 0),
  ladder:       { Pn: 8.0, Pg: 6.0, Sn: 4.6, Lg: [3.6, 3.2] } km/s,
  windows:      [−2 s, +8 s] P  /  group Lg,
  filter:       first-difference cascade, coefficients (1, −1) applied 4×, integer-only;
                both per-sample-rate variants (20 sps, 40 sps) stated verbatim,
  onset:        { sta: <sealed samples>, lta: <sealed samples>,
                  trigger: STA·2^a > LTA·2^b with <sealed a, b>,
                  tie_break: first crossing },
  discriminant: unique m with (ΣLg²)^64·2^m ≤ (ΣP²)^64 < (ΣLg²)^64·2^(m+1)
                (1/64-bit log2 buckets; big-int powers, shifts, comparisons only),
  threshold:    <sealed integer>,
  jitter:       ±30 s, applied to BOTH classes,
  negatives:    <sealed ComCat query URL — magnitude type, tolerance, depth ceiling, time span>,
  s2_bound:     <sealed acceptance percentage of negatives non-explosion-side>,
  annex:        per-region quarry-blast Form (NCEDC stations + their own ladder), sealed separately,
  monthly_draw: { seed: derived from month string, query: <sealed URL>, match_rule: <sealed> },
  holdout:      2010-05-12 (clock: Zhang & Wen 2015 origin time, waveform-fitted → jittered;
                waveform presence at sealed stations VERIFIED before scoring;
                empty-SNR verdict: NO-SIGNAL, recorded raw)
}

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Success criteria

Stated honestly, the four items are not all gates. S1 and S2 are gates with sealed decision rules (S1's leave-one-event-out protocol; S2's sealed acceptance bound). S3 is a gate contingent on a future event that may never occur, kept decidable by an annual attestation. S4 is a published finding, not a gate. Every outcome is recorded raw; a recorded failure is a finding, never renamed.

• S1 — Historical separation, leave-one-out. With the ladder, windows, filter, onset detector, and 1/64-bit bucketing fixed as above, run nine leave-one-event-out folds: refit the integer threshold on the remaining five positives + two near-site negatives, then score the held-out event at IC.MDJ 00.BHZ from raw archived counts, exact integers only. S1 passes only if all nine held-out events land on their correct side. The in-sample fit of the sealed threshold on all 6 + 3 is additionally published as a fit report, not a gate — a free integer boundary optimized on nine events can separate them by construction. Any misplacement is recorded raw.
• S2 — Open-population transfer. The threshold sealed under S1 — untouched — is then run against regional earthquakes within 500 km selected by the Form's sealed negative-corpus query (a literal ComCat URL fixing magnitude type, tolerance, depth ceiling, and time span before the run), and against the reviewed quarry blast corpus under the per-region annex Form (NCEDC stations — the exhibited corpus is Californian and unobservable at IC.MDJ/IU.INCN; no reviewed quarry blast labels within regional distance of the sealed stations were verified in ComCat). Acceptance bound, sealed with the threshold: at least <sealed percentage> of the pre-specified negatives fall non-explosion-side. Every verdict, pass or fail, is recorded raw with its integer bucket value; both classes run the ±30 s clock-jitter control and the (station × phase) lag shear is published per event.
• S3 — Future event, pre-committed. For the next announced explosion-class event to enter ComCat within the standing-law radius (a future DPRK test — the quarry/mine-blast fallback clause is removed, since no eventtype-labeled blast within the radius has been verified to exist), the sealed Form issues its verdict from the catalog clock and raw counts alone, with the Form's sealed_at timestamp — a required field; S3 is not live until it exists — preceding the event's origin time. Verdict published either way. There has been no DPRK test since 2017-09-03 and the event may never occur, so S3 carries a decidable standing check: an annual attestation, recorded raw, that the Form still re-verifies and that zero qualifying events entered ComCat that year.
• S4 — The contested holdout (published finding, not a gate). The 2010-05-12 event is scored by the sealed Form — never trained on — using the Zhang & Wen 2015 origin time as its clock (waveform-fitted, hence jittered exactly like the earthquake-side clocks), and its integer verdict published, alongside the note that expert ground truth there is itself unresolved. Before scoring, usable waveforms at the sealed stations must be verified present in the FDSN archive; an Lg-1.44 event sits at or below the single-station noise floor at Δ ≈ 370 km, so if the windows return only noise the published verdict is NO-SIGNAL with its raw bucket values — recorded, not renamed.

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Honest limits

What this study is not:

• Not a multi-site law. Six positives, one site, one geology. The discriminant can silently learn the Punggye-ri path instead of explosion physics. The near-site negatives (same path: 2017-09-23, 2017-10-12, the collapse) are the built-in control, but transportability to any other test site is unproven and is not claimed here.
• Not treaty monitoring. This program is not CTBTO. No IMS arrays (the KSRS and USRK stations behind the published D² > 21,000 array results (REPORTED; the single-station high-band figure verified from the fetched abstract is D² > 100) are IMS assets, absent from the open FDSN archive), no beamforming, no radionuclide channel. The honest scope is single-station regional discrimination, and verdicts read "consistent / inconsistent with announced-explosion shape at these stations" — never "confirmed nuclear".
• Not a verdict machine below the floor. Below ~mL 2, the expert literature disagrees with itself (the 2010-05-12 stalemate). A "failure" there falsifies nothing; the event stays a scored holdout.
• Not a cross-epoch amplitude study. IC.MDJ instrument responses swapped in 2013 and 2016, with sample-rate/location-code changes in 2016 (VERIFIED). Absolute count magnitudes are not comparable across years; only within-record ratios are admissible, and any metric that accidentally compares raw counts across epochs is invalid.
• Not blind to its own circularity. Catalog origin times for both classes are fitted from the waveform — the positives' clocks are not external either, and no listed archive carries a pre-detonation announced time. The ±30 s jitter control exists exactly because feeding a catalog clock to the ladder is partially circular; it runs on both classes, and the control is written into the sealed Form.

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Status: OPEN — charter published, corpus not yet ingested. Nothing here is sealed until the corpus runs.