Premium
Global trends in extremal microseism intensity
Author(s) -
Aster Richard C.,
McNamara Daniel E.,
Bromirski Peter D.
Publication year - 2010
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2010gl043472
Subject(s) - microseism , geology , seismology , storm , swell , seismic noise , wind wave , wave height , rayleigh wave , climatology , surface wave , geophysics , meteorology , oceanography , geography , telecommunications , computer science
Globally ubiquitous seismic background noise peaks near 7 and 14 s period are generated via distinct mechanisms that transfer storm‐generated gravity wave energy to the seismic wave field. We utilize continuous digital ground motion data recorded by the Global Seismographic Network and precursor instrumentation to chronicle microseism power extreme events for 1972–2009. Because most land‐observed microseism surface‐wave energy is generated at or near coasts, microseism metrics are particularly relevant to assessing changes in coastal ocean wave energy. Extreme microseism winter storm season event counts reveal the widespread influence of the El Niño Southern Oscillation (ENSO). Individual station and ensemble slopes trend positive for this study period for Northern Hemisphere stations. The double‐frequency microseism is particularly volatile, suggesting that the weaker single‐frequency microseism directly generated by ocean swell at coasts is likely a more representative seismic proxy for broad‐scale ocean wave energy estimation.