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Global Trends in Microseism Amplitude on a Warming Planet

Description: 

Earth's microseism wavefield is incessantly excited by wave-wave and wave-solid Earth coupling processes and constitutes the dominant global long-period seismic source process in the absence of earthquakes. The primary and secondary microseism bands reflect integrated geographically extensive ocean wave forces applied to both the ocean floor and upon coastal regions and are uniquely integrative proxies for large-scale ocean wave state. Previous microseism studies have thus utilized microseism metrics to explore spatiotemporal trends in storm intensity, storm tracking, sea ice extent and ocean wave attenuation, and other variability in the weather and climate system. I will summarize results from a new and frequency-domain analysis methodology incorporating continuous long-operational calibrated global seismic data to the near present to extract frequency-domain primary and secondary microseism intensity metrics, and to assess and interpret their periodic and secular regional to global features. A number of atmospheric reanalysis and modeling studies now indicate that Earth’s storm and ocean surface wind intensity is broadly increasing across multi-decade time scales under the influence of climate-change attributed storm intensification. This analysis shows that increasing storm intensity is also apparent in global microseism amplitudes. This is most apparent in the primary microseism band which most directly reflects wave amplitudes along Earth’s coastal regions.

Session: Advancing Science With Global Seismological and Geophysical Networks

Type: Oral

Date: 4/18/2023

Presentation Time: 04:45 PM (local time)

Presenting Author: Richard C. Aster

Student Presenter: No

Invited Presentation: 

Authors