Fiber-Optic Network Observations of Earthquake Wavefields

Autor: Lindsey, NJ, Martin, ER, Dreger, DS, Freifeld, B, Cole, S, James, SR, Biondi, BL, Ajo-Franklin, JB
Rok vydání: 2017
Předmět:
Zdroj: Geophysical Research Letters, vol 44, iss 23
Lindsey, NJ; Martin, ER; Dreger, DS; Freifeld, B; Cole, S; James, SR; et al.(2017). Fiber-Optic Network Observations of Earthquake Wavefields. Geophysical Research Letters, 44(23), 11-799. doi: 10.1002/2017GL075722. Lawrence Berkeley National Laboratory: Retrieved from: http://www.escholarship.org/uc/item/4q12j9t1
Popis: ©2017. American Geophysical Union. All Rights Reserved. Our understanding of subsurface processes suffers from a profound observation bias: seismometers are sparse and clustered on continents. A new seismic recording approach, distributed acoustic sensing (DAS), transforms telecommunication fiber-optic cables into sensor arrays enabling meter-scale recording over tens of kilometers of linear fiber length. We analyze cataloged earthquake observations from three DAS arrays with different horizontal geometries to demonstrate some possibilities using this technology. In Fairbanks, Alaska, we find that stacking ground motion records along 20 m of fiber yield a waveform that shows a high degree of correlation in amplitude and phase with a colocated inertial seismometer record at 0.8–1.6 Hz. Using an L-shaped DAS array in Northern California, we record the nearly vertically incident arrival of an earthquake from The Geysers Geothermal Field and estimate its backazimuth and slowness via beamforming for different phases of the seismic wavefield. Lastly, we install a fiber in existing telecommunications conduits below Stanford University and show that little cable-to-soil coupling is required for teleseismic P and S phase arrival detection.
Databáze: OpenAIRE