PFUSRC-037:A Study of Earth's Internal Structure, Fluid Motion and Earthquake Distribution Based on the 45° Triple Coaxial Biconical Topology System — Limitations of the Ideal Spherical Symmetry Hypothesis and Reconstruction of the Biconical Topological Model

Traditional geophysics generally adopts the ideal spherical symmetry hypothesis to describe Earth’s layered structure. Although this assumption brings mathematical convenience, it encounters prominent logical contradictions when interpreting multiple geophysical observational phenomena. This paper first points out a core dilemma of the spherical symmetry model: it cannot reasonably explain the long-term morphological stability of the liquid outer core under extreme high-pressure conditions from the perspective of fluid mechanics. On this basis, this paper systematically examines its explanatory limitations for large low-shear-velocity provinces (LLSVPs), seismic anisotropy, inner core differential rotation and global earthquake distribution, and verifies that relevant mainstream explanations are mostly empirical summaries rather than deductions from first principles. Based on the established 45° triple coaxial biconical global topology system of the PFUSRC framework, together with its intrinsic constant ₁=12/11, prime node hierarchical stratification, Sevenfold Logic and ₁ field projection operator, this paper reconstructs a new biconical topological model for the Earth. The model consists of a penetrating rigid biconical skeleton, a liquid metal interlayer constrained by topological geometry, a rotatable and oscillatory central inner bicone, and the ₁ field interfacial barrier that prevents cross-layer fluid leakage. According to the topological structure and deep fluid motion rules, this paper deduces the global zonal distribution law of earthquakes: the polar regions correspond to seismic quiescent zones, the central annular waist ring matches the three major global seismic belts, and the inclined conical surfaces form transitional seismic activity zones. Relying on the intrinsic constant 12/11, this paper puts forward a series of testable quantitative predictions, including the aspect ratio of major LLSVPs, fractal dimension of the core-mantle boundary and characteristic spacing ratio of mantle plumes. The biconical topological model effectively resolves the inherent defects of the ideal spherical symmetry hypothesis. Combined with the stellar topological model (PFUSRC-036), this research forms the Star-Planet Unified Topology Theory, providing a new fundamental theoretical framework for exploring the unified structural laws of celestial bodies in the universe.