Accurate Magnitude and Stress Drop using the Empirical Green's Function
Method Applied to Distributed Acoustic Sensing
Abstract
The reliable estimation of earthquake magnitude and stress drop are key
in seismology. The novel technology of distributed acoustic sensing
(DAS) holds great promise for source parameter inversion owing to the
measurements’ high spatial density. In this study, I demonstrate the
robustness of DAS for magnitude and stress drop estimation using the
empirical Green’s function deconvolution method. This method is applied
to 7 colocated earthquakes recorded in Israel following the 2023 Turkey
earthquakes. Spectral ratios were calculated using amplitude spectra
stacked along the fiber, and fitted with a relative Boatwright source
spectral model. Excellent fits were obtained even for similar sized
earthquakes. Stable seismic moments and stress drops were calculated
assuming the moment of one earthquake is known. These robust source
parameters suggest that stress drop increases with seismic moment. The
results demonstrate the great potential of DAS for source studies.