Regional Earthquake Magnitude Conversion Relations for the Himalayan Seismic Belt

2020 ◽  
Vol 91 (6) ◽  
pp. 3195-3207
Author(s):  
Rajiv Kumar ◽  
Ram Bichar Singh Yadav ◽  
Silvia Castellaro
Keyword(s):  
Moment Tensor ◽  
Earthquake Magnitude ◽  
Seismic Belt ◽  
Centroid Moment Tensor ◽  
Moment Tensor Solution ◽  
Magnitude Conversion ◽  
Magnitude Scales ◽  
Regression Relations ◽  
Regional Earthquake ◽  
Earthquake Magnitude Conversion

Abstract We present regional earthquake magnitude conversion relations among different magnitude scales (Mw, Ms, mb, ML, and MD) for the Himalayan seismic belt developed from data of local, regional, and international seismological agencies (International Seismological Centre [ISC], National Earthquake Information Centre [NEIC], Global Centroid Moment Tensor Solution [CMT], International Data Centre [IDC], China Earthquake Administration [BJI], and National Centre for Seismology [NDI]). The intra- (within the same magnitude scale) and inter- (with different magnitude scales) magnitude regression relations have been established using the general orthogonal regression and orthogonal distance regression techniques. Results show that the intra-magnitude relations for Mw, Ms, and mb reported by the Global CMT, ISC, and NEIC exhibit 1:1 relationships, whereas ML reported by the IDC, BJI, and NDI deviates from this relationship. The IDC underestimates Ms and mb compared with the ISC, NEIC, and Global CMT; this may be due to different measurement procedures adopted by the IDC agency. The inter-magnitude relations are established between Mw,Global CMT and Ms, mb, and ML reported by the ISC, NEIC, IDC, and NDI, and compared with the previously developed regional and global regression relations. The duration (MD) and local (ML) magnitudes reported by NDI exhibit a 1:1 relationship. The derived magnitude regression relations are expected to support the homogenization of the earthquake catalogs and to improve seismic hazard assessment in this region.

Earthquake Magnitude Conversion Problem

2018 ◽  
Vol 108 (4) ◽  
pp. 1995-2007 ◽  
Author(s):  
Ranjit Das ◽  
H. R. Wason ◽  
Gabriel Gonzalez ◽  
M. L. Sharma ◽  
Deepankar Choudhury ◽  
...  
Keyword(s):  
Earthquake Magnitude ◽  
Magnitude Conversion ◽  
Earthquake Magnitude Conversion

Future Large Earthquake Analysis of Sulawesi Island Using Satellite Images and Moment Tensor Solution Approach

2022 ◽  
Author(s):  
Catur Cahyaningsih
Keyword(s):  
Hazard Analysis ◽  
Moment Tensor ◽  
Large Earthquake ◽  
Seismic Source ◽  
Shuttle Radar Topography Mission ◽  
Centroid Moment Tensor ◽  
Solution Approach ◽  
Moment Tensor Solution ◽  
Earthquake Sources ◽  
Active Tectonic

Sulawesi Island is the active tectonic region, where the tectonic architecture and potential earthquake sources until now remain largely unknown. The worst earthquake, an Mw 7.5 on September 28, 2018, in Palu, Indonesia, was caused catastrophic damage to life and property. The earthquake has highlighted the urgent need to raise knowledge of the cause of possible large future earthquakes and vulnerability. The main objective for this project is to create a thorough earthquake probabilistic hazard analysis map of the region, which is presently unavailable to better prepare for future earthquakes. The neotectonic and structural map was created using was supplemented with the 30-m resolution Shuttle Radar Topography Mission, Centroid Moment Tensor (CMT) solution, and seismologic data. The results demonstrate that faulting controls the geometry and the majority of these faults are active and capable of causing medium to large magnitude earthquakes with moment magnitudes ranging from 6.2 to 7.5 from 44 seismic sources. Our results show Sulawesi's northern deformation regimes have high seismicity risk and vulnerability. This study contributes a realistic seismic source for the Sulawesi neotectonic area particularly at the northwest, north, and east deformation regime, to understand the key large future earthquakes.

scholarly journals A seismic hazard analysis considering uncertainty during earthquake magnitude conversion

2013 ◽  
Vol 1 (3) ◽  
pp. 2109-2126
Author(s):  
J. P. Wang ◽  
Y. Xu
Keyword(s):  
Seismic Hazard ◽  
Hazard Analysis ◽  
Analytical Framework ◽  
Earthquake Magnitude ◽  
Seismic Hazard Analysis ◽  
Local Magnitude ◽  
Empirical Relationships ◽  
Magnitude Conversion ◽  
Earthquake Magnitude Conversion ◽  
Earthquake Data

Abstract. The magnitude of earthquakes can be described with different units, such as moment magnitude Mw and local magnitude ML. A few empirical relationships between the two have been suggested, such as the model calibrated with the earthquake data in Taiwan. Understandably, such a conversion relationship through regression analysis is associated with some error because of inevitable data scattering. Therefore, the underlying scope of this study is to conduct a seismic hazard analysis, during which the uncertainty from earthquake magnitude conversion was properly taken into account. With a new analytical framework developed for this task, it was found that there is a 10% probability in 50 yr that PGA could exceed 0.28 g at the study site in North Taiwan.

Application of Mwp to deep and teleseismic earthquakes

1999 ◽  
Vol 89 (5) ◽  
pp. 1345-1351 ◽  
Author(s):  
Seiji Tsuboi ◽  
Paul M. Whitmore ◽  
Thomas J. Sokolowski
Keyword(s):  
Moment Tensor ◽  
Earthquake Magnitude ◽  
Moment Magnitude ◽  
Centroid Moment Tensor ◽  
Shallow Earthquakes ◽  
Japanese Islands ◽  
Tsunami Warnings ◽  
Size Estimates ◽  
Good Agreement

Abstract The broadband moment magnitude Mwp (Tsuboi, et al., 1995) allows for the effective determination of earthquake magnitude by using broadband P waveforms. It was developed to determine moment magnitude of shallow earthquakes around the Japanese Islands for early tsunami warnings. Tsuboi et al. (1995) demonstrated that Mwp shows good agreement with the Mw from Harvard centroid moment tensor (CMT) solutions. In the present study, we show that Mwp is also applicable to deep earthquakes and earthquakes recorded at teleseismic distances. The Mwp proves to be useful for quick, accurate size estimates of earthquakes recorded at both regional and teleseismic distances occurring at any depth.

scholarly journals Quick regional centroid moment tensor solutions for the Emilia 2012 (northern Italy) seismic sequence

2012 ◽  
Vol 55 (4) ◽  
Author(s):  
Silvia Pondrelli ◽  
Simone Salimbeni ◽  
Paolo Perfetti ◽  
Peter Danecek
Keyword(s):  
Moment Tensor ◽  
Mediterranean Area ◽  
Northern Italy ◽  
Seismic Sequence ◽  
Centroid Moment Tensor ◽  
Strong Earthquakes ◽  
Magnitude Range ◽  
The Mediterranean ◽  
Centroid Moment Tensor Solutions

<p>In May 2012, a seismic sequence struck the Emilia region (northern Italy). The mainshock, of Ml 5.9, occurred on May 20, 2012, at 02:03 UTC. This was preceded by a smaller Ml 4.1 foreshock some hours before (23:13 UTC on May 19, 2012) and followed by more than 2,500 earthquakes in the magnitude range from Ml 0.7 to 5.2. In addition, on May 29, 2012, three further strong earthquakes occurred, all with magnitude Ml ≥5.2: a Ml 5.8 earthquake in the morning (07:00 UTC), followed by two events within just 5 min of each other, one at 10:55 UTC (Ml 5.3) and the second at 11:00 UTC (Ml 5.2). For all of the Ml ≥4.0 earthquakes in Italy and for all of the Ml ≥4.5 in the Mediterranean area, an automatic procedure for the computation of a regional centroid moment tensor (RCMT) is triggered by an email alert. Within 1 h of the event, a manually revised quick RCMT (QRCMT) can be published on the website if the solution is considered stable. In particular, for the Emilia seismic sequence, 13 QRCMTs were determined and for three of them, those with M &gt;5.5, the automatically computed QRCMTs fitted the criteria for publication without manual revision. Using this seismic sequence as a test, we can then identify the magnitude threshold for automatic publication of our QRCMTs.</p>

scholarly journals New Updated Classification of Shallow Earthquakes Based on Faulting Style

2020 ◽  
pp. 103-111
Author(s):  
Emad Abulrahman Mohammed Salih Al-Heety
Keyword(s):  
Return Period ◽  
Moment Tensor ◽  
Focal Depth ◽  
Strike Slip ◽  
Shallow Depth ◽  
Main Trend ◽  
Maximum Magnitude ◽  
Centroid Moment Tensor ◽  
Significant Information

Earthquakes occur on faults and create new faults. They also occur on  normal, reverse and strike-slip faults. The aim of this work is to suggest a new unified classification of Shallow depth earthquakes based on the faulting styles, and to characterize each class. The characterization criteria include the maximum magnitude, focal depth, b-constant value, return period and relations between magnitude, focal depth and dip of fault plane. Global Centroid Moment Tensor (GCMT) catalog is the source of the used data. This catalog covers the period from Jan.1976 to Dec. 2017. We selected only the shallow (depth less than 70kms) pure, normal, strike-slip and reverse earthquakes (magnitude ≥ 5) and excluded the oblique earthquakes. The majority of normal and strike-slip earthquakes occurred in the upper crust, while the reverse earthquakes occurred throughout the thickness of the crust. The main trend for the derived b-values for the three classes was: b normal fault>bstrike-slip fault>breverse fault.  The mean return period for the normal earthquake was longer than that of the strike-slip earthquakes, while the reverse earthquakes had the shortest period. The obtained results report the relationship between the magnitude and focal depth of the normal earthquakes. A negative significant correlation between the magnitude and dip class for the normal and reverse earthquakes is reported. Negative and positive correlation relations between the focal depth and dip class were recorded for normal and reverse earthquakes, respectively. The suggested classification of earthquakes provides significant information to understand seismicity, seismtectonics, and seismic hazard analysis.

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