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Measuring Shallow Seismic Attenuation in the Pacific Northwest of the United States Using Ambient Noise Seismology

Description: 

Owing to the impact on ground motion levels, seismic attenuation is one of the major components of seismic hazard assessment. Active tectonic regions tend to exhibit elevated attenuation and complex structures. This is notably evident in the Pacific Northwest of the United States, a region known for its combination of active volcanoes and active tectonics. We employ passive noise interferometry on hundreds of broadband seismic stations in the Pacific Northwest to measure seismic attenuation properties. The NoisePy package is utilized to calculate the single-station correlation functions from both permanent and temporary stations. Subsequently, we model the envelope of the cross-correlation coda waves by using the 2-D radiative transfer equation for scalar waves to estimate the intrinsic absorption parameters of Rayleigh waves. Through the best fit between observed and synthetic energy density functions of the envelopes of the coda, we derive the intrinsic absorption parameter of the medium. We analyze the data in multiple frequency bands, obtain the intrinsic absorption parameter, and transfer it into intrinsic attenuation factor Q. Finally, we explore the spatial variations in the observed attenuation parameters and discuss their values in the geodynamical context of the region.

Session: How Well Can We Predict Broadband Site-Specific Ground Motion and Its Spatial Variability So Far? [Poster Session]

Type: Poster

Date: 5/1/2024

Presentation Time: 08:00 AM (local time)

Presenting Author: Kuan-Fu

Student Presenter: No

Invited Presentation: 

Authors