Seismic Velocity Variations at Different Depths Reveal the Dynamic Evolution Associated With the 2018 Kilauea Eruption

Abstract

AbstractAdvances in noise‐based velocity change measurements have revealed anomalies before volcanic eruptions. Still, it is difficult to assign them to a certain depth based on the traditional coda wave method. Here we used volcanic tremor (1–2.5 s) and oceanic noise (3 and 3.5 s) as passive sources to calculate the Rayleigh wave velocity changes associated with the 2018 Kilauea eruption. Our simulation show that the velocity decreased at least by 5% at 1–2 km depth beneath the East Rift zone in the co‐eruption time. Before the eruption, we observed a decrease (1%) at the same depth, whereas, at the depths of 0–1 and 2–8 km, the velocity increased by 0.2%–1%. Combined with microearthquakes, The Global Positioning System data, and numerical simulation, our observations suggest that magma intrusion may open the magma dike at 1–2 km depth but induce higher compressive stress (about 3.6–14.4 MPa) in the surrounding areas.