A Seismic Moment Magnitude Scale

2019 ◽  
Vol 109 (4) ◽  
pp. 1542-1555 ◽  
Author(s):  
Ranjit Das ◽  
Mukat Sharma ◽  
Deepankar Choudhury ◽  
Gabriel Gonzalez
Keyword(s):  
Seismic Moment ◽  
Moment Magnitude ◽  
Magnitude Scale ◽  
Seismic Moment Magnitude

Source Parameters and Seismic Moment-Magnitude Scaling for Northwestern Turkey

2007 ◽  
Vol 97 (2) ◽  
pp. 655-660 ◽  
Author(s):  
S. Parolai ◽  
D. Bindi ◽  
E. Durukal ◽  
H. Grosser ◽  
C. Milkereit
Keyword(s):  
Seismic Moment ◽  
Source Parameters ◽  
Moment Magnitude ◽  
Magnitude Scaling ◽  
Northwestern Turkey ◽  
Seismic Moment Magnitude

On the mN, M Relation for Eastern North American Earthquakes

1987 ◽  
Vol 58 (4) ◽  
pp. 119-124 ◽  
Author(s):  
Gail M. Atkinson ◽  
David M. Boore
Keyword(s):  
North America ◽  
Stochastic Model ◽  
Ground Motion ◽  
Seismic Moment ◽  
The Other ◽  
Moment Magnitude ◽  
Scaling Relations ◽  
Eastern North America ◽  
Data Set ◽  
Meaningful Data

Abstract A stochastic model of ground motion has been used as a basis for comparison of data and theoretically-predicted relations between mN (commonly denoted by mbLg) and moment magnitude for eastern North America (ENA) earthquakes. mN magnitudes are recomputed for several historical ENA earthquakes, to ensure consistency of definition and provide a meaningful data set. We show that by itself the magnitude relation cannot be used as a discriminant between two specific spectral scaling relations, one with constant stress and the other with stress increasing with seismic moment, that have been proposed for ENA earthquakes.

scholarly journals Analysis of strong-motion data of the 1990 Eastern Sicily earthquake

1995 ◽  
Vol 38 (2) ◽  
Author(s):  
M. Di Bona ◽  
M. Cocco ◽  
A. Rovelli ◽  
R. Berardi ◽  
E. Boschi
Keyword(s):  
Frequency Band ◽  
Stress Drop ◽  
Seismic Moment ◽  
Ground Motions ◽  
Broad Band ◽  
Strong Motion ◽  
Moment Magnitude ◽  
Corner Frequency ◽  
Local Magnitude ◽  
The Moment

The strong motion accelerograms recorded during the 1990 Eastern Sicily earthquake have been analyzed to investigate source and attenuation parameters. Peak ground motions (peak acceleration, velocity and displacement) overestimate the values predicted by the empirical scaling law proposed for other Italian earthquakes, suggesting that local site response and propagation path effects play an important role in interpreting the observed time histories. The local magnitude, computed from the strong motion accelerograms by synthesizing the Wood-Anderson response, is ML = 5.9, that is sensibly larger than the local magnitude estimated at regional distances from broad-band seismograms (ML = 5.4). The standard omega-square source spectral model seems to be inadequate to describe the observed spectra over the entire frequency band from 0.2 to 20 Hz. The seismic moment estimated from the strong motion accelerogram recorded at the closest rock site (Sortino) is Mo = 0.8 x 1024 dyne.cm, that is roughly 4.5 times lower than the value estimated at regional distances (Mo = 3.7 x 1024 dyne.cm) from broad-band seismograms. The corner frequency estimated from the accelera- tion spectra i.5 J; = 1.3 Hz, that is close to the inverse of the dUl.ation of displacement pulses at the two closest recording sites. This value of corner tì.equency and the two values of seismic moment yield a Brune stress drop larger than 500 bars. However, a corner frequency value off; = 0.6 Hz and the seismic moment resulting from regional data allows the acceleration spectra to be reproduced on the entire available frequency band yielding to a Brune stress drop of 210 bars. The ambiguity on the corner frequency value associated to this earthquake is due to the limited frequency bandwidth available on the strong motion recordil1gs. Assuming the seismic moment estimated at regional distances from broad-band data, the moment magnitude for this earthquake is 5.7. The higher local magnitude (5.9) compared with the moment magnitude (5.7) is due to the weak regional attenuation. Beside this, site amplifications due to surface geology have produced the highest peak ground motions among those observed at the strong motion sites.

On moment-magnitude scale

1980 ◽  
Vol 70 (1) ◽  
pp. 379-383 ◽  
Author(s):  
S. K. Singh ◽  
J. Havskov
Keyword(s):  
Moment Magnitude ◽  
Magnitude Scale

Emergency with Resiliency Equals Efficiency – Challenges of an EMT-3 in Nepal

2018 ◽  
Vol 33 (6) ◽  
pp. 673-677 ◽  
Author(s):  
Avraham Yitzhak ◽  
Ofer Merin ◽  
Jonathan Halevy ◽  
Bader Tarif
Keyword(s):  
Hospitalization Rate ◽  
Moment Magnitude ◽  
Magnitude Scale ◽  
Medical Team ◽  
Publication Type ◽  
Emergency Medical Team ◽  
Wound Debridement ◽  
Disaster Area ◽  
Emergency Medical

AbstractThe 7.8 MW (moment magnitude scale) earthquake that hit Nepal on April 25, 2015 caused significant casualties and serious damage to infrastructure.The Israeli Emergency Medical Team (IEMT; later verified as EMT-3) was deployed 80 hours after the earthquake. A Forward Disaster Scout Team (FDST) that was dispatched to the disaster area a few hours after the disaster relayed pre-deployment information.The EMT staff was comprised of 42 physicians. A total of 1,668 patients were treated. The number of non-trauma cases increased as the days went by. The hospitalization rate was 31%. Wound debridement procedures were the most common operations performed.YitzhakA, MerinO, HalevyJ, TarifB. Emergency with resiliency equals efficiency- challenges of an EMT-3 in Nepal. Prehosp Disaster Med. 2018;33(6):673–677.

scholarly journals Seismic Moment Tensor Solutions from GeoNet Data to Provide a Moment Magnitude Scale for New Zealand

2021 ◽  
Author(s):  
◽  
Elizabeth de Joux Robertson
Keyword(s):  
New Zealand ◽  
Seismic Moment ◽  
Moment Tensor ◽  
Velocity Model ◽  
Moment Tensor Inversion ◽  
Moment Magnitude ◽  
Seismic Moment Tensor ◽  
Waveform Data ◽  
Moment Tensors ◽  
The Moment

<p>The aim of this project is to enable accurate earthquake magnitudes (moment magnitude, MW) to be calculated routinely and in near real-time for New Zealand earthquakes. This would be done by inversion of waveform data to obtain seismic moment tensors. Seismic moment tensors also provide information on fault-type. I use a well-established seismic moment tensor inversion method, the Time-Domain [seismic] Moment Tensor Inversion algorithm (TDMT_INVC) and apply it to GeoNet broadband waveform data to generate moment tensor solutions for New Zealand earthquakes. Some modifications to this software were made. A velocity model can now be automatically used to calculate Green's functions without having a pseudolayer boundary at the source depth. Green's functions can be calculated for multiple depths in a single step, and data are detrended and a suitable data window is selected. The seismic moment tensor solution that has either the maximum variance reduction or the maximum double-couple component is automatically selected for each depth. Seismic moment tensors were calculated for 24 New Zealand earthquakes from 2000 to 2005. The Global CMT project has calculated CMT solutions for 22 of these, and the Global CMT project solutions are compared to the solutions obtained in this project to test the accuracy of the solutions obtained using the TDMT_INVC code. The moment magnitude values are close to the Global CMT values for all earthquakes. The focal mechanisms could only be determined for a few of the earthquakes studied. The value of the moment magnitude appears to be less sensitive to the velocity model and earthquake location (epicentre and depth) than the focal mechanism. Distinguishing legitimate seismic signal from background seismic noise is likely to be the biggest problem in routine inversions.</p>

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