Premium
Estimation of the attenuation operator for multiple‐ ScS waves using digitally recorded broadband data
Author(s) -
Sipkin Stuart A.
Publication year - 1988
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl015i008p00832
Subject(s) - attenuation , geology , waveform , broadband , residual , geodesy , seismology , great circle , telecommunications , physics , optics , geometry , mathematics , computer science , algorithm , radar
Broadband multiple‐ ScS waveforms have been obtained for several deep‐focus earthquakes in the Izu‐Okhotsk region from the intermediate‐period channels of the RSTN network. Differential travel times have been computed by waveform cross‐correlation. Estimates of the multiple‐ ScS attenuation operator have been obtained using a phase‐equalization and stacking technique. For this mixed, but mostly tectonic path crossing the eastern margin of Asia and northwestern North America we obtain a median ScS n ‐ ScS n−1 travel time residual of +0.6s with respect to the J‐B velocity model and a Q ScS of 182±21 over the frequency band 0.017‐0.117Hz. In this band there is no apparent frequency dependence. We find that the Aleutian back‐arc region and central Alaska is slower and has a higher attenuation than the rest of the path. Even though the data contain much higher frequencies, beyond ∼0.117 Hz the multiple‐ ScS phases lose coherence and the results become unstable.