Within-type magnitude gradients gave no clear positive time-direction signal in Ridgecrest events on days 1 to 30

We tested whether larger moment-magnitude events have a larger future-minus-past nearby event count in a fixed USGS Ridgecrest catalog. We used 79 preferred mw anchors on days 1 to 30 after the 2019 M7.1 event. Neighbors have magnitude at least 2.5 and lie within 10 minutes and 5 km. The continuous magnitude slope, after removal of day and 10 km cell means, was -0.177 events per magnitude unit. A within-group magnitude shuffle gave a one-sided p value of 0.593 and a central 95% reference range of -1.339 to 1.323. This range is not a confidence interval. Only 26 anchors were in groups with variation in both magnitude and score. Nine checks also gave no clear positive signal. These results add a within-type test to an earlier mixed-type size test. They do not show that physical productivity is independent of magnitude. Sparse local groups, one sequence, preferred magnitude selection, and missed events limit the test. We provide scores, code, null draws, source hashes, and an independent count and variance audit.

Ridgecrest · aftershocks · magnitude type · time direction · conditional permutation · null result