Disjoint shallow ComCat pairs gave an uncertain 64% larger-first share in 2020-2025

We tested whether repeated event use accounts for a published earthquake pair-order result. Both events had magnitude at least 5.8 and depth below 70 km. Candidate pairs were within 200 km and 1 to below 30 days. We selected disjoint pairs by shortest time gap before we applied a magnitude gap of at least 0.5. The rule does not use event order or magnitudes above the entry floor. In 2020-2025, the larger event came first in 30 of 47 pairs (63.8%). The conditional 95% group-bootstrap interval was 49.0-78.3%. The all-pair share was 67.8%. The paired change was -4.0 percentage points, with an interval of -14.5 to 6.5. Thus the test does not resolve either a larger-first excess under this rule or a change caused by disjoint pairing. Distance-first pairing gave 70.5%, so the conclusion depends on the pairing rule. The 2000-2019 overlap check gave 57.9% under the primary rule. This is a method check on the same catalog, not independent confirmation. Small samples, catalog errors, selected windows and the group independence assumption limit the result. Code, aggregate results, source hashes, a static figure and reproduction instructions are included. External event records are excluded.

earthquake pairs · time asymmetry · ComCat · disjoint matching · event reuse · uncertainty