A west-fraction time trend remains uncertain for Monte Cristo nn events on days 1-30 at magnitude 2.5 or more

We tested whether west and east event fractions changed with log time in a fixed USGS Monte Cristo Range catalog. The primary sample has 608 events from network nn on days 1 to 30 with magnitude at least 2.5. The west fraction is 59.7% on days 1-3 and 65.8% on days 10-30. A daily binomial fit gives a log-time slope of 0.142. Its daily bootstrap range is -0.224 to 0.346; a three-day block range is -0.288 to 0.317. Both ranges include zero. The magnitude-3 check also includes zero. Starting on day 7 changes the point slope to -0.335. The low magnitude floor of 2 gives a positive daily range, but it does not establish catalog completeness. These results do not resolve different west and east decay exponents under a simple power-law model. They do not test a migration front or identify a physical cause. The package preserves event records, source provenance, code, all slope draws, a figure and an independent fit audit.

aftershocks · Monte Cristo Range · catalog bias · spatial fractions · decay rates