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.

scholarly journals Attenuation relationships of peak ground motions in the Jazan Region

2021 ◽  
Vol 14 (3) ◽  
Author(s):  
Ali K. Abdelfattah ◽  
Abdullah Al-amri ◽  
Kamal Abdelrahman ◽  
Muhamed Fnais ◽  
Saleh Qaysi
Keyword(s):  
Saudi Arabia ◽  
Ground Motions ◽  
Prediction Equation ◽  
Peak Ground Velocity ◽  
Local Magnitude ◽  
Ground Acceleration ◽  
Data Set ◽  
Hypocentral Distance ◽  
Distance Range ◽  
Attenuation Relationships

AbstractIn this study, attenuation relationships are proposed to more accurately predict ground motions in the southernmost part of the Arabian Shield in the Jazan Region of Saudi Arabia. A data set composed of 72 earthquakes, with normal to strike-slip focal mechanisms over a local magnitude range of 2.0–5.1 and a distance range of 5–200 km, was used to investigate the predictive attenuation relationship of the peak ground motion as a function of the hypocentral distance and local magnitude. To obtain the space parameters of the empirical relationships, non-linear regression was performed over a hypocentral distance range of 4–200 km. The means of 638 peak ground acceleration (PGA) and peak ground velocity (PGV) values calculated from the records of the horizontal components were used to derive the predictive relationships of the earthquake ground motions. The relationships accounted for the site-correlation coefficient but not for the earthquake source implications. The derived predictive attenuation relationships for PGV and PGA are$$ {\log}_{10}(PGV)=-1.05+0.65\cdotp {M}_L-0.66\cdotp {\log}_{10}(r)-0.04\cdotp r, $$ log 10 PGV = − 1.05 + 0.65 · M L − 0.66 · log 10 r − 0.04 · r , $$ {\log}_{10}(PGA)=-1.36+0.85\cdotp {M}_L-0.85\cdotp {\log}_{10}(r)-0.005\cdotp r, $$ log 10 PGA = − 1.36 + 0.85 · M L − 0.85 · log 10 r − 0.005 · r , respectively. These new relationships were compared to the grand-motion prediction equation published for western Saudi Arabia and indicate good agreement with the only data set of observed ground motions available for an ML 4.9 earthquake that occurred in 2014 in southwestern Saudi Arabia, implying that the developed relationship can be used to generate earthquake shaking maps within a few minutes of the event based on prior information on magnitudes and hypocentral distances taking into considerations the local site characteristics.

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>

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 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>

EMCAT: An automatic image-processing system for electron-microscopic tomography

1994 ◽  
Vol 52 ◽  
pp. 418-419
Author(s):  
Weiping Liu ◽  
John W. Sedat ◽  
David A. Agard
Keyword(s):  
Image Processing ◽  
Structural Information ◽  
Imaging Technique ◽  
Three Dimensional ◽  
Processing System ◽  
Electron Microscopic ◽  
Data Set ◽  
Ordered Structures ◽  
Automatic Image Processing ◽  
Em Tomography

Any real world object is three-dimensional. The principle of tomography, which reconstructs the 3-D structure of an object from its 2-D projections of different view angles has found application in many disciplines. Electron Microscopic (EM) tomography on non-ordered structures (e.g., subcellular structures in biology and non-crystalline structures in material science) has been exercised sporadically in the last twenty years or so. As vital as is the 3-D structural information and with no existing alternative 3-D imaging technique to compete in its high resolution range, the technique to date remains the kingdom of a brave few. Its tedious tasks have been preventing it from being a routine tool. One keyword in promoting its popularity is automation: The data collection has been automated in our lab, which can routinely yield a data set of over 100 projections in the matter of a few hours. Now the image processing part is also automated. Such automations finish the job easier, faster and better.

A driver drowsiness and distraction warning system based on raspberry Pi 3 Kit

2019 ◽  
Vol 70 (3) ◽  
pp. 184-192
Author(s):  
Toan Dao Thanh ◽  
Vo Thien Linh
Keyword(s):  
Processing System ◽  
Warning System ◽  
Raspberry Pi ◽  
Data Set ◽  
Lower Lip ◽  
Driver Drowsiness ◽  
Image Sensing ◽  
The Face ◽  
The Common ◽  
University Laboratory

In this article, a system to detect driver drowsiness and distraction based on image sensing technique is created. With a camera used to observe the face of driver, the image processing system embedded in the Raspberry Pi 3 Kit will generate a warning sound when the driver shows drowsiness based on the eye-closed state or a yawn. To detect the closed eye state, we use the ratio of the distance between the eyelids and the ratio of the distance between the upper lip and the lower lip when yawning. A trained data set to extract 68 facial features and “frontal face detectors” in Dlib are utilized to determine the eyes and mouth positions needed to carry out identification. Experimental data from the tests of the system on Vietnamese volunteers in our University laboratory show that the system can detect at realtime the common driver states of “Normal”, “Close eyes”, “Yawn” or “Distraction”

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 Evidence for Publicly Reported Quality Indicators in Residential Long-Term Care: A Systematic Review

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 181-181
Author(s):  
Franziska Zúñiga ◽  
Magdalena Osinska ◽  
Franziska Zuniga
Keyword(s):  
New Zealand ◽  
Quality Indicators ◽  
Long Term Care ◽  
Grey Literature ◽  
Public Reporting ◽  
Assessment Instrument ◽  
Term Care ◽  
Data Set ◽  
Residential Long Term Care

Abstract Quality indicators (QIs) are used internationally to measure, compare and improve quality in residential long-term care. Public reporting of such indicators allows transparency and motivates local quality improvement initiatives. However, little is known about the quality of QIs. In a systematic literature review, we assessed which countries publicly report health-related QIs, whether stakeholders were involved in their development and the evidence concerning their validity and reliability. Most information was found in grey literature, with nine countries (USA, Canada, Australia, New Zealand and five countries in Europe) publicly reporting a total of 66 QIs in areas like mobility, falls, pressure ulcers, continence, pain, weight loss, and physical restraint. While USA, Canada and New Zealand work with QIs from the Resident Assessment Instrument – Minimal Data Set (RAI-MDS), the other countries developed their own QIs. All countries involved stakeholders in some phase of the QI development. However, we only found reports from Canada and Australia on both, the criteria judged (e.g. relevance, influenceability), and the results of structured stakeholder surveys. Interrater reliability was measured for some RAI QIs and for those used in Germany, showing overall good Kappa values (&gt;0.6) except for QIs concerning mobility, falls and urinary tract infection. Validity measures were only found for RAI QIs and were mostly moderate. Although a number of QIs are publicly reported and used for comparison and policy decisions, available evidence is still limited. We need broader and accessible evidence for a responsible use of QIs in public reporting.

Moment-tensor solutions for the 24 November 1987 Superstition Hills, California, earthquakes

1989 ◽  
Vol 79 (2) ◽  
pp. 493-499
Author(s):  
Stuart A. Sipkin
Keyword(s):  
Main Shock ◽  
Moment Tensor ◽  
Time Dependent ◽  
Origin Time ◽  
Data Set ◽  
Filter Theory ◽  
Long Period ◽  
Seismograph Network ◽  
Scalar Moment

Abstract The teleseismic long-period waveforms recorded by the Global Digital Seismograph Network from the two largest Superstition Hills earthquakes are inverted using an algorithm based on optimal filter theory. These solutions differ slightly from those published in the Preliminary Determination of Epicenters Monthly Listing because a somewhat different, improved data set was used in the inversions and a time-dependent moment-tensor algorithm was used to investigate the complexity of the main shock. The foreshock (origin time 01:54:14.5, mb 5.7, Ms 6.2) had a scalar moment of 2.3 × 1025 dyne-cm, a depth of 8 km, and a mechanism of strike 217°, dip 79°, rake 4°. The main shock (origin time 13:15:56.4, mb 6.0, Ms 6.6) was a complex event, consisting of at least two subevents, with a combined scalar moment of 1.0 × 1026 dyne-cm, a depth of 10 km, and a mechanism of strike 303°, dip 89°, rake −180°.

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