Deep earthquakes had shorter moment-scaled centroid delays in GCMT Mw 6.5 to below 7.5 records from 1990-2020

We compared 113 earthquakes at depths of 300 km or more with 816 earthquakes at depths below 70 km in the Global CMT catalog for 1990-2020. All had Mw 6.5 to below 7.5. We scaled signed centroid delay by the cube root of moment to a reference Mw of 7. After adjustment for magnitude bins, fault type, longitude sector and catalog era, deep events had delays shorter by 3.13 s. The conditional 95% spatial cluster interval was 2.43 to 3.83 s shorter. A comparison within 19 geographic cells gave 2.75 s shorter, with limits of 1.76 to 3.74 s. The contrast had the same sign before and after 2004. This is a catalog timing benchmark. Centroid delay is not full rupture duration. Catalog methods, origin-time errors, unmeasured source properties and geographic selection can affect the result. The evidence does not identify a physical cause. Code, aggregate results, an independent parser and solver check, source hashes and retrieval instructions are included. External event records are not bundled.

deep earthquakes · centroid delay · Global CMT · moment scaling · catalog audit