Broadband Lg Attenuation Modeling in the Middle East
Abstract
We present a broadband tomographic model of Lg attenuation in the Middle East derived from source- and site-corrected amplitudes. Absolute amplitude measurements are made on hand-selected and carefully windowed seismograms for tens of stations and thousands of crustal earthquakes resulting in excellent coverage of the region. A conjugate gradient method is used to tomographically invert the amplitude dataset of over 8000 paths over a 45{sup o} x 40{sup o} region of the Middle East. We solve for Q variation, as well as site and source terms, for a wide range of frequencies ranging from 0.5-10 Hz. We have modified the standard attenuation tomography technique to more explicitly define the earthquake source expression in terms of the seismic moment. This facilitates the use of the model to predict the expected amplitudes of new events, an important consideration for earthquake hazard or explosion monitoring applications. The attenuation results have a strong correlation to tectonics. Shields have low attenuation, while tectonic regions have high attenuation, with the highest attenuation at 1 Hz is found in eastern Turkey. The results also compare favorably to other studies in the region made using Lg propagation efficiency, Lg/Pg amplitude ratios and two-station methods. We tomographically invert themore »
- Authors:
- Publication Date:
- Research Org.:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Org.:
- USDOE
- OSTI Identifier:
- 958180
- Report Number(s):
- LLNL-JRNL-406566
Journal ID: ISSN 0956-540X; TRN: US201002%%85
- DOE Contract Number:
- W-7405-ENG-48
- Resource Type:
- Journal Article
- Journal Name:
- Geophysical Journal International
- Additional Journal Information:
- Journal Volume: 177; Journal Issue: 3; Journal ID: ISSN 0956-540X
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 58 GEOSCIENCES; AMPLITUDES; ATTENUATION; EARTHQUAKES; EFFICIENCY; EXPLOSIONS; FREQUENCY DEPENDENCE; MIDDLE EAST; MONITORING; SHIELDS; SIMULATION; SOURCE TERMS; TECTONICS; TOMOGRAPHY; TURKEY
Citation Formats
Pasyanos, M E, Matzel, E M, Walter, W R, and Rodgers, A J. Broadband Lg Attenuation Modeling in the Middle East. United States: N. p., 2008.
Web.
Pasyanos, M E, Matzel, E M, Walter, W R, & Rodgers, A J. Broadband Lg Attenuation Modeling in the Middle East. United States.
Pasyanos, M E, Matzel, E M, Walter, W R, and Rodgers, A J. 2008.
"Broadband Lg Attenuation Modeling in the Middle East". United States. https://www.osti.gov/servlets/purl/958180.
@article{osti_958180,
title = {Broadband Lg Attenuation Modeling in the Middle East},
author = {Pasyanos, M E and Matzel, E M and Walter, W R and Rodgers, A J},
abstractNote = {We present a broadband tomographic model of Lg attenuation in the Middle East derived from source- and site-corrected amplitudes. Absolute amplitude measurements are made on hand-selected and carefully windowed seismograms for tens of stations and thousands of crustal earthquakes resulting in excellent coverage of the region. A conjugate gradient method is used to tomographically invert the amplitude dataset of over 8000 paths over a 45{sup o} x 40{sup o} region of the Middle East. We solve for Q variation, as well as site and source terms, for a wide range of frequencies ranging from 0.5-10 Hz. We have modified the standard attenuation tomography technique to more explicitly define the earthquake source expression in terms of the seismic moment. This facilitates the use of the model to predict the expected amplitudes of new events, an important consideration for earthquake hazard or explosion monitoring applications. The attenuation results have a strong correlation to tectonics. Shields have low attenuation, while tectonic regions have high attenuation, with the highest attenuation at 1 Hz is found in eastern Turkey. The results also compare favorably to other studies in the region made using Lg propagation efficiency, Lg/Pg amplitude ratios and two-station methods. We tomographically invert the amplitude measurements for each frequency independently. In doing so, it appears the frequency-dependence of attenuation is not compatible with the power law representation of Q(f), an assumption that is often made.},
doi = {},
url = {https://www.osti.gov/biblio/958180},
journal = {Geophysical Journal International},
issn = {0956-540X},
number = 3,
volume = 177,
place = {United States},
year = {Thu Aug 21 00:00:00 EDT 2008},
month = {Thu Aug 21 00:00:00 EDT 2008}
}