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Ambient Seismic Noise for Imaging and Monitoring Volcán De Colima

Description: 

Understanding the shallow magma storage and magmatic plumbing system of a volcano is key to its monitoring. We have gained new insight into the internal structure of Volcán de Colima by generating a high-resolution three-dimensional shear-wave velocity tomography using ambient seismic noise recorded on the Colima Volcanic Complex and a neighborhood technique.
Our findings show a network of NE-SW low-velocity zones that are oriented along a local fault system. The overlap of a negative radial anisotropy with the low-velocity zone indicates that magma follows vertically oriented structures, such as interfingered dikes or faults and cracks with a significant vertical component. The difference between the currently active system, connected to a network of fluid-filled dikes, and the former active system, filled with solidified sills and dikes, is highlighted by the contrast between the low-velocity anomaly under Volcán de Colima and the distinct high-velocity anomaly under Nevado de Colima.
This velocity model has directly impacted the monitoring of the volcano using ambient seismic noise. Cross-correlations of ambient noise can be used to measure temporal fluctuations of relative seismic velocity in various frequency bands, which reveal information about stress or strain perturbations at various depths. We precisely and quickly retrieve the velocity variations in many frequency bands at once by monitoring seismic velocity variation using wavelet transforms. This improves the depth localization of the source of velocity change in the shallow crust, finely constrained by the high-resolution velocity model.

Session: Crustal Imaging of High Seismic Hazard Regions

Type: Oral

Date: 4/20/2023

Presentation Time: 08:30 AM (local time)

Presenting Author: Raphael S. M. De Plaen

Student Presenter: No

Invited Presentation: 

Authors