Earthquakes as probing tools for gravity theories

We propose a novel method for testing gravity models using seismic data from Earth. By imposing observational constraints on Earth’s moment of inertia and mass, we rigorously limit the gravitational models’ parameters within a $2\sigma$ accuracy. Our method constrains the parameters governing additional terms to the General Relativity Lagrangian to the following ranges: $-2\times {10}^9\lesssim \beta \lesssim {10}^9{\text{m}}^2$ for Palatini $f(R)$ gravity, $-8\times {10}^9\lesssim \epsilon \lesssim 4\times {10}^9{\text{m}}^2$ for Eddington-inspired Born-Infeld gravity, and $-{10}^{-3}\lesssim \mathrm{{\rm Y}}\lesssim {10}^{-3}$ for Degenerate Higher-Order Scalar-Tensor theories. We also discuss potential avenues to enhance the proposed method, aiming to impose even tighter constraints on gravity models.