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Theoretical limits on detection and analysis of small earthquakes
Author(s) -
Kwiatek Grzegorz,
BenZion Yehuda
Publication year - 2016
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.983
H-Index - 232
eISSN - 2169-9356
pISSN - 2169-9313
DOI - 10.1002/2016jb012908
Subject(s) - seismogram , seismology , geology , waveform , amplitude , acoustics , attenuation , noise (video) , shear (geology) , signal (programming language) , ambient noise level , physics , computer science , optics , telecommunications , petrology , sound (geography) , radar , artificial intelligence , image (mathematics) , programming language
We investigate theoretical limits on detection and reliable estimates of source characteristics of small earthquakes using synthetic seismograms for shear/tensile dislocations on kinematic circular ruptures and observed seismic noise and properties of several acquisition systems (instrument response, sampling rate). Simulated source time functions for shear/tensile dislocation events with different magnitudes, static stress drops, and rupture velocities provide estimates for the amplitude and frequency content of P and S phases at various observation angles. The source time functions are convolved with a Green's function for a homogenous solid assuming given P , S wave velocities and attenuation coefficients and a given instrument response. The synthetic waveforms are superposed with average levels of the observed ambient seismic noise up to 1 kHz. The combined seismograms are used to calculate signal‐to‐noise ratios and expected frequency content of P and S phases at various locations. The synthetic simulations of signal‐to‐noise ratio reproduce observed ratios extracted from several well‐recorded data sets. The results provide guidelines on detection of small events in various geological environments, along with information relevant to reliable analyses of earthquake source properties.