Open AccessSpectral analysis of seismic noise induced by rivers: A new tool to monitor spatiotemporal changes in stream hydrodynamics
Author(s) -
Burtin A.,
Bollinger L.,
Vergne J.,
Cattin R.,
Nábělek J. L.
Publication year - 2008
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2007jb005034
Subject(s) - seismic noise , ambient noise level , geology , noise (video) , passive seismic , seismology , amplitude , precipitation , environmental science , geomorphology , meteorology , sound (geography) , physics , quantum mechanics , artificial intelligence , computer science , image (mathematics)
Analysis of continuous seismic data recorded by a dense passive seismological network (Hi‐CLIMB) installed across the Himalayas reveals strong spatial and temporal variations in the ambient seismic energy produced at high frequencies (>1 Hz). From June to September 2003, the high‐frequency seismic noise is observed to increase up to 20 dB (relative to (m/s) 2 /Hz) for all the stations located along a steep 30‐km‐long narrow and deeply incised channel of the Trisuli River, a major trans‐Himalayan river. The early summer increase in high‐frequency energy is modulated by a 24‐h periodicity where the minimum of seismic noise level is reached around noon and the maximum is reached late in the evening. A detailed study of seismic noise amplitude reveals a clear correlation with both regional meteorological and hydrological data along the Trisuli River. Seasonal increase in ambient noise coincides with the strong monsoon rainfall and a period of rapid melting of snow and ice in the high elevations. The observed 24‐h cyclicity is consistent with the daily fluctuation of the precipitation and river discharge in the region. River‐induced seismic noise is partly generated by stream turbulence, but this mechanism fails to explain the observed clockwise hysteresis of seismic noise amplitude versus water level. This pattern is better explained if a significant part of the observed seismic noise is caused by ground vibrations generated by bed load transport. This points out the potential of using background seismic noise to quantify in continuous river bed load and monitor its spatial variations, which remain difficult with classical approaches.