A Unified Geophysical Framework for Megathrust Earthquake Forecasting via Sexagesimal Harmony Algorithm (SHA), Thermo-Poroelasticity, and Spectral Entropy Collapse: Application to the Nankai Trough Megathrust System (2026–2027)

### Abstract This record contains the complete theoretical manuscript, mathematical proofs, and high-performance C++ implementation of the **Sexagesimal Harmony Algorithm (SHA / AAS)** integrated within the **Costa Rica Seismological Prediction Algorithm (ASCR)** framework. By generalizing modular arithmetic over the ring b Z_60, continuous spatio-temporal seismic catalogs are projected into discrete residue manifolds to isolate locked structural asperities, blind fault corridors, and transient stress gaps. To resolve non-linearities driven by fluid ascension and thermal weakening, the model introduces a non-isothermal thermo-poroelastic coupling operator into the scalar potential field ψ (fx), alongside a dynamic **Maat Balance Operator (M)** and a **Modular Temporal Spectral Entropy (H(r_t))** decay metric. ### Key Contributions & Applications * **Mathematical Formalization:** Rigorous proofs demonstrating the modular temporal spectral entropy collapse (H(r_t) \to 0) as a precursor indicator of critical elasto-static fault locking. * **Thermo-Poroelastic Coupling:** Integration of geothermal gradients (d T/dz) and pore-pressure dynamics (P_f) into effective normal stress calculations (∑_n'). * **High-Performance Code:** Standalone C++ computational engine for calculating modular residual matrices and spectral entropy distributions. * **Global Megathrust Application:** Detailed application to the **Nankai Trough megathrust system (Japan)**, incorporating historical seismicity (Kumamoto 2016, Noto Peninsula 2024, Hyūganada 2024–2026). * **2026 Forecast:** Provides a deterministic-probabilistic forecast estimating a multisectional cascade megathrust event (8.4 M_w 8.8, 52% ±4% probability) within the critical window of **November 18 to December 08, 2026**. ### Metadata & Archival Info * **Author:** Ing. Jorge Alexander López Miranda (Aliya Logic Systems) * **ORCID iD:** [0009-0008-4226-1555](https://orcid.org/0009-0008-4226-1555) * **Target Concept DOI:** 10.5281/zenodo.22941034