Seismic Signals from the Hydrosphere Occurring Beyond the Microseism Band

Session: Environmental and Near Surface Seismology: From Glaciers and Rivers to Engineered Structures and Beyond
Type: Oral
Date: 4/29/2020
Time: 09:30 AM
Room: 110 + 140
Description: 

Broadband seismometers across the globe ubiquitously record microseism energy generated by ocean waves interacting with both each other and continental shorelines. Typically, microseism energy dominates a period band of 3-20 s and has been studied extensively for several decades. However, several novel seismic signals generated by large bodies of water exist outside of this period band. Because these signals are not as immediately apparent in seismic records, they have received less attention and many questions still surround their generation mechanisms. First, we revisit recent work utilizing freeze-thaw events to characterize ~0.5-3 s seismic energy arising from gravity waves on large lakes. This energy can be observed several hundred km from the shorelines of lakes and has consistent period regardless of swell period in the lake. We then show that local swell activity can be observed on near-shore (< 1 km) seismometers at periods as low as 0.2 s. Turning to longer-period energy, we revisit observations of a 26 s microseism peak observed on quiet seismic stations across the globe that is thought to originate from the Gulf of Guinea. Finally, we explore unique, tidally modulated, long-period (> 50 s) spectral peaks observed at several island sites across the Pacific Ocean basin.

Presenting Author: Robert E. Anthony

Authors