Microseism source distribution inferred from noise recordings at the Gujarat Seismic Network, India

We analyse continuous seismic ambient noise data recorded by the Gujarat Seismic Network during 2015 to characterise ambient noise sources and their directionality. We use probabilistic power spectral densities and single-station three-component polarisation techniques to estimate the noise levels a...

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Bibliographic Details
Published in:Journal of Earth System Science 2022-03, Vol.131 (1), p.23, Article 23
Main Authors: Bhatia, Monika, Rajesh, Rekapalli, Ravi Kumar, M, Agrawal, M
Format: Article
Language:English
Subjects:
Ambient noise
Azimuth
Coastal zone
Distribution
Earth and Environmental Science
Earth Sciences
Earthquakes
Eigenvalues
Fourier transforms
Microseisms
Noise levels
Polarization
Seasonal variation
Seasonal variations
Space Exploration and Astronautics
Space Sciences (including Extraterrestrial Physics
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Summary:We analyse continuous seismic ambient noise data recorded by the Gujarat Seismic Network during 2015 to characterise ambient noise sources and their directionality. We use probabilistic power spectral densities and single-station three-component polarisation techniques to estimate the noise levels at individual stations and noise source azimuthal distribution. The spectral power at short- and long-period ambient noise in the coastal regions of the southern part of Gujarat matches well with the global high-noise models, whereas the noise level in the northern part is in conformity with the global mean. Quarterly variation of power in the primary (PM) and secondary microseism (SM) bands suggests high-noise levels during the monsoon season. We observed high and moderate PM and SM noise powers at stations near the faults in the Kachchh region and the coastal areas of southern Gujarat, respectively. The azimuths of strong PM and SM sources estimated from the single-station polarisation method indicate that the main sources of noise are in the Indian Ocean and the Arabian Sea. We also observed a seasonal variation in the polarised signal azimuth and power. In addition to the noise source distribution, analysis of spatially averaged ambient noise levels in the PM and SM bands suggests a possible association of ambient noise levels with subsurface characteristics and regional faults in the study area.
ISSN:2347-4327
0253-4126
0973-774X
DOI:10.1007/s12040-021-01779-9