Microseism noise in the Philippine Sea [poster] 

Abstract

Microseism noise, generated by wave-wave interaction of ocean surface gravity waves and peaking between 0.1 and 0.5Hz, is the largest amplitude, continuous (acceleration) vibration on earth in the seismic band from 0.0001 to 10Hz. Although microseisms have been studied extensively over the past seventy years, significant issues remain regarding their excitation and propagation. In a recent paper Bromirski et al (JGR, 2013) point out that there is an important distinction between microseisms generated in deep and shallow water. Most microseisms observed on continents are generated in shallow water near coastlines. Microseisms generated in deep water are observed on seafloor sensors but do not transition readily to continents. The Ocean Bottom Seismometer Augmentation to the Philippine Sea (OBSAPS) Experiment has provided a unique opportunity to study the excitation and propagation of microseism noise (from 0.05 to 1.0Hz) in the oceans by combining ocean bottom seismometer observations with co-located and simultaneous observations of the acoustic field in the ocean. The depth dependence of the acoustic field in the ocean is used to distinguish between ocean acoustic modes and acoustic and elastic pseudo-Rayleigh waves as propagation mechanisms for microseism energy.