资源环境科技发展态势分析平台

Advances 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 s 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 km and 2–8 km, the velocity increased by 0.2–1%. Combined with microearthquakes, GPS 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 in the surrounding areas.