A Passive Estimation Method of Scattering and Intrinsic Absorption Parameters From Envelopes of Seismic Ambient Noise Cross-Correlation Functions

We present a passive method to estimate the scattering and intrinsic absorption parameters of Rayleigh waves. Envelopes of seismic ambient noise cross-correlation functions are calculated using the temporal flattening technique, and these parameters are estimated by modeling their space-time distributions using radiative transfer theory. The scattering mean free paths are estimated to be 1.6–2.4 km at 0.5–1 Hz, 1.6–2.0 km at 1–2 Hz, and 1.6–3.2 km at 2–4 Hz at the Sakurajima volcano, Japan. Intrinsic absorption parameters are 0.04–0.06 s⁻¹ at 0.5–1 Hz, 0.08–0.09 s⁻¹ at 1–2 Hz, and 0.16–0.18 s⁻¹ at 2–4 Hz. We validate these values by conducting a comparative study using active shot records at Sakurajima. Our passive method provides an effective way to measure scattering and intrinsic absorption parameters in various regions.