Amplitude tomography reconstructs seismic attenuation directly from recorded wave amplitudes. We have applied the tomography to amplitude data reported in the 'Annual Bulletin of Chinese Earthquakes' and interpreted the regionally varying crustal attenuation in terms of tectonics. The seismic amplitudes were originally recorded for determining the M-L and M-S magnitudes. They generally correspond to the maximum amplitudes of the horizontal components of the short-period S waves and intermediate-period Rayleigh waves. Both sets of measurements are sensitive to crustal structure. The peak amplitudes from M-L amplitudes spread spherically with significant dispersion and scattering. M-S amplitudes show cylindrical spreading with little dispersion. Average crustal Q values for attenuation at 1 Hz are 737 and 505 for M-L and M-S, respectively, with substantial regional variations. Frequency dependence in the attenuation is also indicated. Regions with the lowest attenuation (high Q values) are beneath the south China Block, Sichuan Basin, Ordos Platform, the Daxinganling and the Korea Craton. These tend to be tectonically inactive regions, which are generally dominated by intrusive and cratonic rocks in the upper crust. Regions with the highest attenuation (low Q values) are beneath Bohai Basin, Yunnan, eastern Songpan-Ganzi Terrain, margins of the Ordos platform and the Qilian Shan. These are predominantly active basins, grabens and fold belts. The continental margin also highly attenuates both S and surface waves.
Hearn, Thomas M.; Ni, James F. New Mexico State Univ, Dept Phys, Las Cruces, NM 88003 USA. Wang, Suyun; Xu, Zhonghuai; Yu, Yanxiang China Earthquake Adm, Inst Geophys, Beijing 100081, Peoples R China. Pei, Shunping Chinese Acad Sci, Inst Tibetan Plateau Res, Beijing 100085, Peoples R China.
%0 Journal Article
%1 Hearn:2008
%A Hearn, T. M.
%A Wang, S. Y.
%A Pei, S. P.
%A Xu, Z. H.
%A Ni, J. F.
%A Yu, Y. X.
%C OXFORD
%D 2008
%I BLACKWELL PUBLISHING
%J GEOPHYSICAL JOURNAL INTERNATIONAL
%K CHINA; CODA-Q; EVOLUTION; EXHUMATION FACTOR; HIGH-PRESSURE LG NORTH QUALITY REGIONS; ROCKS; STRUCTURE; SURROUNDING UPPER-MANTLE; VELOCITY WAVE-PROPAGATION;
%N 1
%P 223--234
%R 10.1111/j.1365-246X.2008.03776.x
%T Seismic amplitude tomography for crustal attenuation beneath China
%V 174
%X Amplitude tomography reconstructs seismic attenuation directly from recorded wave amplitudes. We have applied the tomography to amplitude data reported in the 'Annual Bulletin of Chinese Earthquakes' and interpreted the regionally varying crustal attenuation in terms of tectonics. The seismic amplitudes were originally recorded for determining the M-L and M-S magnitudes. They generally correspond to the maximum amplitudes of the horizontal components of the short-period S waves and intermediate-period Rayleigh waves. Both sets of measurements are sensitive to crustal structure. The peak amplitudes from M-L amplitudes spread spherically with significant dispersion and scattering. M-S amplitudes show cylindrical spreading with little dispersion. Average crustal Q values for attenuation at 1 Hz are 737 and 505 for M-L and M-S, respectively, with substantial regional variations. Frequency dependence in the attenuation is also indicated. Regions with the lowest attenuation (high Q values) are beneath the south China Block, Sichuan Basin, Ordos Platform, the Daxinganling and the Korea Craton. These tend to be tectonically inactive regions, which are generally dominated by intrusive and cratonic rocks in the upper crust. Regions with the highest attenuation (low Q values) are beneath Bohai Basin, Yunnan, eastern Songpan-Ganzi Terrain, margins of the Ordos platform and the Qilian Shan. These are predominantly active basins, grabens and fold belts. The continental margin also highly attenuates both S and surface waves.
@article{Hearn:2008,
abstract = {Amplitude tomography reconstructs seismic attenuation directly from recorded wave amplitudes. We have applied the tomography to amplitude data reported in the 'Annual Bulletin of Chinese Earthquakes' and interpreted the regionally varying crustal attenuation in terms of tectonics. The seismic amplitudes were originally recorded for determining the M-L and M-S magnitudes. They generally correspond to the maximum amplitudes of the horizontal components of the short-period S waves and intermediate-period Rayleigh waves. Both sets of measurements are sensitive to crustal structure. The peak amplitudes from M-L amplitudes spread spherically with significant dispersion and scattering. M-S amplitudes show cylindrical spreading with little dispersion. Average crustal Q values for attenuation at 1 Hz are 737 and 505 for M-L and M-S, respectively, with substantial regional variations. Frequency dependence in the attenuation is also indicated. Regions with the lowest attenuation (high Q values) are beneath the south China Block, Sichuan Basin, Ordos Platform, the Daxinganling and the Korea Craton. These tend to be tectonically inactive regions, which are generally dominated by intrusive and cratonic rocks in the upper crust. Regions with the highest attenuation (low Q values) are beneath Bohai Basin, Yunnan, eastern Songpan-Ganzi Terrain, margins of the Ordos platform and the Qilian Shan. These are predominantly active basins, grabens and fold belts. The continental margin also highly attenuates both S and surface waves.},
added-at = {2010-08-12T23:06:12.000+0200},
address = {OXFORD},
af = {Hearn, Thomas M. Wang, Suyun Pei, Shunping Xu, Zhonghuai Ni, James F. Yu, Yanxiang},
author = {Hearn, T. M. and Wang, S. Y. and Pei, S. P. and Xu, Z. H. and Ni, J. F. and Yu, Y. X.},
author-address = {[Hearn, Thomas M.; Ni, James F.] New Mexico State Univ, Dept Phys, Las Cruces, NM 88003 USA. [Wang, Suyun; Xu, Zhonghuai; Yu, Yanxiang] China Earthquake Adm, Inst Geophys, Beijing 100081, Peoples R China. [Pei, Shunping] Chinese Acad Sci, Inst Tibetan Plateau Res, Beijing 100085, Peoples R China.},
author-keywords = {seismic attenuation; seismic tomography; crustal structure; Asia},
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bdsk-url-1 = {http://dx.doi.org/10.1111/j.1365-246X.2008.03776.x},
biburl = {https://www.bibsonomy.org/bibtex/2bf213f5fb2155f4e906031f6178797e8/jkmacc},
cited-reference-count = {53},
date-added = {2010-04-03 14:45:18 -0600},
date-modified = {2010-04-03 14:45:18 -0600},
document-type = {Article},
doi = {10.1111/j.1365-246X.2008.03776.x},
e-mail-address = {thearn@nmsu.edu},
interhash = {8280e0598de7e2f45645ce614c9ac747},
intrahash = {bf213f5fb2155f4e906031f6178797e8},
isi = {ISI:000256615300017},
isi-document-delivery-number = {311QS},
iso-source-abbreviation = {Geophys. J. Int.},
issn = {0956-540X},
journal = {GEOPHYSICAL JOURNAL INTERNATIONAL},
keywords = {CHINA; CODA-Q; EVOLUTION; EXHUMATION FACTOR; HIGH-PRESSURE LG NORTH QUALITY REGIONS; ROCKS; STRUCTURE; SURROUNDING UPPER-MANTLE; VELOCITY WAVE-PROPAGATION;},
language = {English},
month = Jul,
number = 1,
page-count = {12},
pages = {223--234},
publication-type = {J},
publisher = {BLACKWELL PUBLISHING},
publisher-address = {9600 GARSINGTON RD, OXFORD OX4 2DQ, OXON, ENGLAND},
reprint-address = {Hearn, TM, New Mexico State Univ, Dept Phys, Las Cruces, NM 88003 USA.},
source = {GEOPHYS J INT},
subject-category = {Geochemistry & Geophysics},
times-cited = {2},
timestamp = {2010-08-12T23:06:14.000+0200},
title = {Seismic amplitude tomography for crustal attenuation beneath China},
volume = 174,
year = 2008
}