Pre Seismic Quiescence and Dynamical Regime Transitions in the Japan and Chile Earthquake Catalogs Evidence from KR Critical Slowing Down Indicators

TL;DR

This study introduces the KR excitation regulation framework to detect pre-seismic critical slowing down signals, demonstrating consistent suppression of CSD indicators before major earthquakes across Japan and Chile, validated through synthetic and simulation analyses.

Contribution

The paper presents a novel coupled differential equation system for CSD detection, validated across two subduction zones, advancing earthquake precursor analysis with robust statistical and simulation support.

Findings

CSD indicators are suppressed before large earthquakes in Japan and Chile.

The suppression is statistically significant and consistent across regions.

Synthetic and simulation models confirm the mechanism behind CSD signal suppression.

Abstract

We present the KR excitation regulation framework, a coupled ordinary differential equation system that produces Critical Slowing Down (CSD) indicators from rolling earthquake magnitude windows, and demonstrate independent cross catalog replication of a pre seismic CSD quiescence signal across two subduction zone settings. In the Japan USGS catalog (Mc >= 4.5, N = 14501 events, 2000 to 2022), CSD50 is suppressed by about 17 to 21 percent across four consecutive pre seismic lags (-14, -7, -3, -1 days) before clean M >= 6.0 mainshocks (60 day isolation, n = 41). All four lags survive false discovery rate correction (p = 0.003 to 0.005) and permutation testing (p = 0.004 to 0.012). The same pipeline applied to the Chile USGS catalog (Mc >= 4.5, N = 9150 events, 2000 to 2024) independently reproduces the signal, with suppression of about 18 to 22 percent across the same lags (n = 58, all significant). Effect sizes are statistically indistinguishable between the two regions. The signal is absent in unfiltered catalogs, and rolling b value analysis shows no concurrent change (p > 0.30), indicating a signal distinct from frequency magnitude variation. Synthetic validation identifies the mechanism: variance reduction produces strong suppression (-54 percent, p < 0.001), while rate reduction alone does not (-8.5 percent, p = 0.091). A combined rate and variance scenario (-38 percent, p < 0.001) matches observations. A pure ETAS control shows no false suppression (+28.7 percent, p = 1.000). Rate and state friction simulation produces strong suppression (-60 percent, p < 0.0001), and time shuffle testing confirms temporal dependence (p = 0.004). The KR system identifies four regimes (Markov persistence 0.941; hazard ratio 1.77). CSD100 achieves AUC = 0.549 for M >= 5.5 forecasting, interpreted as a complementary diagnostic. We do not claim spatial universality or deterministic prediction.