DOI: 10.1785/bssa0610061811. A method of correcting<i>P</i>-wave magnitudes for the effect of earthquake focal mechanism

A method of correctingP-wave magnitudes for the effect of earthquake focal mechanism

10.1785/bssa0610061811

Crossref journal-article

Seismological Society of America (SSA)

Bulletin of the Seismological Society of America (790)

Abstract

abstractThis paper presents a methodology for correcting body-wave magnitudes for the effect of focal mechanism in a routine manner. The method requires a knowledge of the prevailing or dominant mechanism for a geographic region, from which tables are constructed which enable one to make the necessary correction. Included in the paper are tables for Aleutian Island, Kamchatka and mid-Atlantic Ocean earthquakes.From a study of seven earthquakes, it is concluded that the present method gives essentially the same average magnitude with the same standard deviation as a more exact method of correcting for the focal mechanism. The latter method uses the focal-mechanism parameters of the earthquake, which must be determined independently for each earthquake.The existing distribution of seismograph stations is such that transform-fault earthquakes of the mid-Atlantic Ocean will consistently have their P-wave magnitudes underestimated by about 0.2 magnitude units, if no correction is made for the focal mechanism. On the other hand, P-wave magnitudes of earthquakes in Kamchatka and south of the axis of the Aleutian Trench will be overestimated by about 0.2 units.

Bibliography

Syed, A. A., & Nuttli, O. W. (1971). A method of correctingP-wave magnitudes for the effect of earthquake focal mechanism. Bulletin of the Seismological Society of America, 61(6), 1811â1826.

Authors 2

Atiq A. Syed (first)
Otto W. Nuttli (additional)

References 22 Referenced 9

{'key': '2021091017595079900_BIB1', 'article-title': 'Investigation of the mechanism of earthquakes', 'volume-title': 'Soviet Research in Geophysics', 'author': 'Bessonova', 'year': '(1960)'} / Soviet Research in Geophysics / Investigation of the mechanism of earthquakes by Bessonova ((1960))
10.1029/JB075i017p03421 / J. Geophys. Res. / Correction for focal mechanism in body-wave magnitude determination by Chandra ((1970))
Duda S. J. (1970). Travel times and body wave magnitude, Saint Louis University, Scientific Report No. 8, Contract AF 19(628)-5100.
{'key': '2021091017595079900_BIB4', 'first-page': '1', 'article-title': 'Magnitude and energy of earthquakes', 'volume': '9', 'author': 'Gutenberg', 'year': '(1956)', 'journal-title': 'Ann. Geofis.'} / Ann. Geofis. / Magnitude and energy of earthquakes by Gutenberg ((1956))
10.1029/JB073i018p05855 / J. Geophys. Res. / Seismology and the new global tectonics by Isacks ((1968))
10.1029/JB075i032p06675 / J. Geophys. Res. / Three-dimensional ray tracing in a laterally heterogeneous spherical Earth by Jacob ((1970))
Jarosch H. S. (1968). Body wave magnitude and source mechanism, Seismic Data Laboratory Report No. 225, Teledyne, Inc., Alexandria, Virginia. (10.21236/AD0842559)
{'key': '2021091017595079900_BIB8', 'first-page': '924', 'article-title': 'On the stresses in the seismic foci of the Atlantic Ocean', 'volume': '10', 'author': 'Misharina', 'year': '(1964)', 'journal-title': 'Bull. Acad. Sci., USSR, Geophys. Ser.'} / Bull. Acad. Sci., USSR, Geophys. Ser. / On the stresses in the seismic foci of the Atlantic Ocean by Misharina ((1964))
10.1785/BSSA0540010141 / Bull. Seism. Soc. Am. / Some observations relating to the effect of the crust on long-period P-wave motion by Nuttli ((1964))
10.1785/BSSA0250010001 / Bull. Seism. Soc. Am. / An instrumental earthquake magnitude scale by Richter ((1935))
10.1016/S0065-2687(08)60527-0 / Advan. Geophys. / The focal mechanism of earthquakes by Stauder ((1962))
10.1029/JB073i012p03847 / J. Geophys. Res. / Mechanism of the Rat Island earthquake sequence of February 4, 1965, with relation to island arcs and sea-floor spreading by Stauder ((1968))
10.1029/JB073i024p07693 / J. Geophys. Res. / Tensional character of earthquake foci beneath the Aleutian trench with relation to sea-floor spreading by Stauder ((1968))
10.1785/BSSA05406B2199 / Bull. Seism. Soc. Am. / The S wave project for focal mechanism studies: Earthquakes of 1962 by Stauder ((1964))
10.1785/BSSA0560061363 / Bull. Seism. Soc. Am. / The S-wave project for focal mechanism studies: Earthquakes of 1963 by Stauder ((1966))
10.1785/BSSA0530010059 / Bull. Seism. Soc. Am. / S-wave studies of earthquakes of the North Pacific, Part II: Aleutian Islands by Stauder ((1963))
{'key': '2021091017595079900_BIB17', 'first-page': '51', 'article-title': 'Station corrections for vertical component P wave amplitude at LASA', 'volume': '40', 'author': 'Syed', 'year': '(1969)', 'journal-title': 'Earthquake Notes'} / Earthquake Notes / Station corrections for vertical component P wave amplitude at LASA by Syed ((1969))
10.1785/BSSA0610061827 / Bull. Seism. Soc. Am. / A seismic discriminant based on focal mechanism by Syed ((1971))
10.1029/JZ072i008p02131 / J. Geophys. Res. / Mechanism of earthquakes and nature of faulting on the mid-oceanic ridges by Sykes ((1967))
10.1029/JB076i005p01113 / J. Geophys. Res. / Temperature field and geophysical effects of a downgoing slab by Toksöz ((1971))
10.1785/BSSA05406A2049 / Bull. Seism. Soc. Am. / Application of numerical method for S-wave focal mechanism determinations to earthquakes of Kamchatka-Kurile Islands region by Udias ((1964))
10.1785/BSSA0600020503 / Bull. Seism. Soc. Am. / The effects of radiation patterns on magnitude estimates by von Seggern ((1970))

Dates

Type	When
Created	3 years, 11 months ago (Sept. 10, 2021, 1:59 p.m.)
Deposited	2 years, 7 months ago (Jan. 8, 2023, 7:02 p.m.)
Indexed	1 year, 6 months ago (Feb. 12, 2024, 1:09 p.m.)
Issued	53 years, 8 months ago (Dec. 1, 1971)
Published	53 years, 8 months ago (Dec. 1, 1971)
Published Online	53 years, 8 months ago (Dec. 1, 1971)
Published Print	53 years, 8 months ago (Dec. 1, 1971)

Funders 0

None

BibTeX

@article{Syed_1971, title={A method of correctingP-wave magnitudes for the effect of earthquake focal mechanism}, volume={61}, ISSN={0037-1106}, url={http://dx.doi.org/10.1785/bssa0610061811}, DOI={10.1785/bssa0610061811}, number={6}, journal={Bulletin of the Seismological Society of America}, publisher={Seismological Society of America (SSA)}, author={Syed, Atiq A. and Nuttli, Otto W.}, year={1971}, month=dec, pages={1811–1826} }

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