Mean depth change was uncertain for M3+ Puerto Rico records on days 1-30 in 2020 and depended on depth-label selection

We tested mean reported depth in a fixed USGS Puerto Rico catalog. We compared days 1-7 with days 7-30 after 7 January 2020, for magnitude 3 or more within 50 km of a fixed center. Mean depth rose from 9.12 to 9.49 km across 211 early and 317 late events. The change was 0.37 km. A conditional 95% two-day block interval was -0.04 to 0.88 km. Excluding exact 5, 10 and 33 km labels raised the change to 0.97 km, with limits 0.51 to 1.50 km. At magnitude 3.5 or more, the change was -0.02 km, with limits -0.86 to 0.85 km. Exact labels do not identify verified fixed-depth solutions. Within local and duration magnitude types, changes gave a positive mean-depth term, but changing type weights opposed that term. Thus type mixing alone does not explain the depth change. Selection and reporting practice limit inference about physical migration. This is a small catalog diagnostic from one revised sequence. It does not test the later migration found in relocated catalogs. The package includes raw data, source hashes, code, event and daily evidence, all resample values, and an independent numerical check.

Puerto Rico · earthquake depth · ComCat · catalog selection · aftershocks · null result · depth labels