Comparison of Magnitude Estimates for New Zealand Earthquakes: Moment Magnitude, Local Magnitude, and Teleseismic Body-Wave Magnitude

2009 ◽  
Vol 99 (3) ◽  
pp. 1841-1852 ◽  
Author(s):  
J. Ristau
Keyword(s):  
New Zealand ◽  
Body Wave ◽  
Moment Magnitude ◽  
Local Magnitude ◽  
Body Wave Magnitude ◽  
Magnitude Estimates

The relationship between teleseismic body-wave magnitude m and local magnitude ML from New Zealand earthquakes

1972 ◽  
Vol 62 (1) ◽  
pp. 1-11
Author(s):  
S. J. Gibowicz
Keyword(s):  
New Zealand ◽  
Linear Relationship ◽  
Body Wave ◽  
Local Magnitude ◽  
The Relationship ◽  
Shallow Focus ◽  
Body Wave Magnitude

Abstract Relationships between the magnitudes ML and m for 123 New Zealand earthquakes occurring between 1950 and 1967 and having 4.6 ≦ ML ≦ 7.3 have been found. Deep- and shallow-focus shocks were considered separately. There is a linear relationship between ML and m, the slope being the same for both deep and shallow events. Values of ML for deep events are consistently 0.5 magnitude larger than those for shallow events having the same value of m. The relationship between m and ML for New Zealand earthquakes differs significantly from that obtained by Gutenberg and Richter in California.

scholarly journals Konversi Empiris Summary Magnitude, Local Magnitude, Body-Wave Magnitude, Surface Magnitude, dan Moment Magnitude Menggunakan Data Gempabumi 1922-2020 di Nusa Tenggara Barat

2021 ◽  
Vol 7 (1) ◽  
pp. 1-12
Author(s):  
Rian Mahendra Taruna ◽  
Anggitya Pratiwi
Keyword(s):  
Body Wave ◽  
Empirical Relation ◽  
Moment Magnitude ◽  
Local Magnitude ◽  
Earthquake Catalogues ◽  
Data Set ◽  
Good Relation ◽  
Using Data ◽  
Earthquake Process ◽  
Body Wave Magnitude

The existence of magnitude type variation from existing earthquake catalogue sources show that uniforming process is necessary. Beside that these type of magnitude will saturates in certain value, which are different with moment magnitude (Mw) which is not saturated and can describe earthquake process better. Our research initially did compatibility test between summary magnitude which is largely used by BMKG with other magnitude type. Furthermore, the purpose of our research is determination of empirical relation between magnitude type summary magnitude (M), local magnitude (ML), body-wave magnitude (mb), dan surface magnitude (Ms) which are usually used by earthquake catalogues to Mw. Method used in this research is linear regression using data set from BMKG, ISC-EHB, USGS, and Global CMT catalogues with are limited in West Nusa Tenggara and surrounding area. Data used in this research contains of 24.703 earthquake events during period May 9th 1922 until June 27th 2020. The result of this research shows there was good relation between M magnitude type with others magnitude type. Our research also found a conversion formula of M, ML, MLv, mb, and Ms to Mw with well-defined correlation.

scholarly journals Calibration of local earthquake magnitudes in Nepal

2011 ◽  
Vol 42 ◽  
pp. 95-100
Author(s):  
S. Rajaure ◽  
B. P. Koirala ◽  
M. Bhattarai ◽  
S. Maske
Keyword(s):  
United States ◽  
Regression Analysis ◽  
Surface Wave ◽  
Body Wave ◽  
Moment Magnitude ◽  
United States Geological Survey ◽  
Local Magnitude ◽  
Local Earthquakes ◽  
Local Earthquake ◽  
International Seismological Centre

An attempt has been made to calibrate magnitudes of local earthquakes recorded by National Seismological Centre (NSC) of the Department of Mines and Geology (DMG), Nepal with other magnitudes of corresponding earthquakes [eported by International Seismological Centre (ISC), UK, and United States Geological Survey (USGS), USA. Local magnitudes (ML) are used from NSC, corresponding surface wave magnitudes (Ms) and body-wave magnitudes (Mb) are used from catalog of ISC and moment magnitude (Mw) is used from catalog of the USGS. After regression analysis, it has been found that the local magnitude s (ML) reported by NSC are slightly larger than Ms, Mb and Mw in all cases. ML, on average, is larger by an amount of about 0.5, than Ms; with an uncertainty of 0.7. Similarly, ML is larger than corresponding Mb by an amount of about 0.6 and the uncertainty is about 0.5. Likewise, ML is larger than Mw by about 1.0 and the corresponding uncertainty is 0.7.

A Depth-Dependent Local Magnitude Scale for New Zealand Earthquakes Consistent with Moment Magnitude

2020 ◽  
Author(s):  
David A. Rhoades ◽  
Annemarie Christophersen ◽  
Sandra Bourguignon ◽  
John Ristau ◽  
Jérôme Salichon
Keyword(s):  
New Zealand ◽  
Reference Model ◽  
Moment Tensor ◽  
Full Range ◽  
Processing System ◽  
Moment Magnitude ◽  
Attenuation Relation ◽  
Local Magnitude ◽  
Data Set ◽  
Hypocentral Distance

ABSTRACT A new reference attenuation model for calculating local magnitude (ML) for New Zealand earthquakes is derived. An earlier reference model, denoted NZ16, was developed in 2016 as a possible alternative to the classical reference model used by GeoNet for earthquakes located by the SeisComP processing system since January 2012. It aimed to provide a logA0 attenuation relation of the amplitude with the hypocentral distance applicable to the New Zealand region and to make ML more consistent with moment magnitude (Mw). For the present update, denoted NZ20, a much larger set of regional moment tensor solutions and corresponding station amplitudes is available. Residual analysis is used to screen the individual station amplitude readings and then to exclude observations from periods of time when the station residuals were consistently anomalous. Effects of other possible sources of bias on the attenuation relation are also examined, including unreliable locations of earthquakes with large azimuthal gaps and the saturation of ML in large earthquakes. An extra explanatory variable is added to the attenuation relation to account for dependence on hypocentral depth, so the updated local magnitude is consistent with Mw across the full range of depths at which earthquakes occur in New Zealand. Furthermore, to counteract possible sources of bias, the data set for analysis is restricted. Earthquakes above the approximate amplitude saturation threshold of Mw 6.6, as well as those with azimuthal gaps greater than 270°, are excluded.

A note on discrepancies between local magnitude (ML) and microearthquake magnitude scales

1973 ◽  
Vol 63 (1) ◽  
pp. 315-319
Author(s):  
Wayne Thatcher
Keyword(s):  
Southern California ◽  
Body Wave ◽  
Wave Spectrum ◽  
Local Network ◽  
Far Field ◽  
Local Magnitude ◽  
Magnitude Scales ◽  
Spectrum Measurements

abstract A necessary correction for relating local network magnitude scales to Richter's local magnitude (ML) involves accounting for the shape of the far-field body-wave spectrum of the phases used for determining magnitude. When not corrected for, this effect causes errors of about one magnitude unit at ML ∼ 3 for some southern California earthquakes. The discrepancy should be comparable for ML > 3, but at smaller magnitudes will decrease with decreasing ML. It may be corrected for either by direct comparison of network scales with magnitudes determined from Wood-Anderson seismograms, or by spectrum measurements over a range of magnitudes. The nature of the discrepancy and the corrections required to account for it are demonstrated by an example, the aftershocks of the 1968 Borrego Mountain, California earthquake.

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