Earthquake Fault Scaling: Self-Consistent Relating of Rupture Length, Width, Average Displacement, and Moment Release

The main objective of the present article is to develop self-consistent empirical relationships between rupture parameters and moment magnitude for the Himalayas. The database includes the fault rupture parameters of significant earthquakes in the Himalayan region and thrusting earthquakes from NGA West-2 database. The existing empirical relationships between magnitude and rupture parameters are reviewed in view of their consistency. The consistent relationships between moment magnitude and rupture parameters are derived and compared with the existing such relationships. The comparison of the developed consistent relationships reveal that the rupture length was being underestimated in the range of magnitude from 7 to 8, whereas it was overestimated in the lower range of magnitudes using inconsistent empirical relationships. While rupture width was overestimated for the entire range of magnitudes using inconsistent relationships, the rupture area was underestimated for magnitude greater than 7.

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A comparison of alternative curve fitting techniques for different earthquake fault parameters of Iranian earthquakes

Earth Sciences Research Journal ◽

10.15446/esrj.v24n4.72068 ◽

2021 ◽

Vol 24 (4) ◽

pp. 459-472

Author(s):

Serkan Ozturk ◽

Mohammad R. Ghassemi ◽

Mahmut Sarı

Keyword(s):

Curve Fitting ◽

Robust Regression ◽

Correlation Coefficients ◽

The Other ◽

Empirical Relationships ◽

Surface Rupture ◽

Earthquake Fault ◽

Orthogonal Regression ◽

Rupture Length ◽

Fault Parameters

In this study, we tried to estimate the optimum linear equations among the parameters associated with different earthquake fault mechanisms for Iranian earthquakes. For this purpose, we tested different curve fitting methods in order to present the most proper empirical relationships between several seismic parameters for different fault systems. In the present paper, 46 large and destructive Iranian earthquakes whose magnitudes change between 5.8 and 7.8 from 1900 to 2014 were used for the analyses. A comparison was made by using four types of curve fitting techniques. The estimation procedures are considered as (1) L2 or Least Squares Regression, (2) L1 or Least Sum of Absolute Deviations Regression, (3) Robust Regression and, (4) Orthogonal Regression. Confidence intervals were selected as 95% for all types of regression relationships. In the selection of the best probability distribution, we considered the correlation coefficients of the linear regressions as a powerful and conceptually simple method. Correlation coefficients of all relationships change between 0.299 and 0.986 with Orthogonal regression, between 0.168 and 0.792 with L1 regression, between 0.059 and 0.829 with Robust regression. For Iranian earthquakes, the most suitable and reliable empirical relationships between moment magnitude (Mw) and surface wave magnitude (Ms), Mw and surface rupture length (SRL), Mw and maximum displacement (MD), and SRL and MD were obtained by Orthogonal regression since it supplies stronger correlation coefficients than those of the other regression techniques in most estimates. The results show that estimated empirical relationships among the different fault parameters by using the Orthogonal regression method can be accepted as more up-to-date and more appropriate in comparison with the other regression norms. Consequently, these equations were suggested as more reliable in the estimation of the maximum surface displacement, maximum surface rupture length and associated with the maximum credible earthquakes for different areas of Iran. Furthermore, obtained relationships can be statistically significant for the assessment of seismic, tectonic and geologic activities, and they can be used to evaluate the rupture hazard of the Iranian Plateau.

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Earthquake Rupture Scaling Relations for Mainland China

Seismological Research Letters ◽

10.1785/0220190129 ◽

2019 ◽

Vol 91 (1) ◽

pp. 248-261 ◽

Cited By ~ 4

Author(s):

Jia Cheng ◽

Yufang Rong ◽

Harold Magistrale ◽

Guihua Chen ◽

Xiwei Xu

Keyword(s):

Eastern China ◽

Mainland China ◽

Plate Boundary ◽

Earthquake Magnitude ◽

Western China ◽

Scaling Relations ◽

Rupture Length ◽

Rupture Area ◽

Length Width ◽

Length Scaling

Abstract Magnitude‐rupture scaling relations describe how the length, width, and area of fault rupture vary with earthquake magnitude. These parameters are required in seismic hazard models to fit the models’ earthquakes onto faults and to define the site‐rupture distances needed in ground‐motion prediction equations. We collected the magnitude and rupture parameters of 91 earthquakes in Mainland China and nearby regions to study magnitude‐rupture scaling relations. We find no systematic deviations for the subsurface rupture length (RLD) obtained from different methods versus earthquake magnitude. We performed regressions of RLD versus magnitude and versus rupture width using general orthogonal regression. Then, we derived the relations between rupture area and magnitude. Our relations are not statistically different from the results derived by others using global datasets, if the parameters of the five pre‐1900 great earthquakes in eastern China are not used. However, if the five earthquakes are used, the magnitude‐rupture length scaling relation for large strike‐slip earthquakes in eastern China gives shorter rupture lengths than earthquakes in western China and other plate boundary regions in the world.

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A distributed-source approach to modelling the spatial distribution of MM intensities resulting from large crustal New Zealand earthquakes

Bulletin of the New Zealand Society for Earthquake Engineering ◽

10.5459/bnzsee.43.2.85-109 ◽

2010 ◽

Vol 43 (2) ◽

pp. 85-109 ◽

Cited By ~ 1

Author(s):

D. J. Dowrick ◽

D. A. Rhoades

Keyword(s):

Spatial Distribution ◽

New Zealand ◽

Current Model ◽

Seismic Source ◽

Ground Shaking ◽

Distributed Source ◽

New Model ◽

Rupture Length ◽

Crustal Earthquakes ◽

Length Width

This paper presents a new approach to modelling the spatial distribution of intensities in crustal earthquakes, using a distributed source. The source is represented by one or two rectangular fault rupture planes of chosen dip, discretised into small rectangles each with its own share of the total seismic moment, and modelling chosen distributions of asperities. The Modified Mercalli (MM) intensity of shaking is represented by isoseismals. Comparisons are made with the actual isoseismals (particularly of intensities MM9 and MM10) of selected large historical crustal New Zealand earthquakes and those predicted by the simpler models of Dowrick & Rhoades (2005). Important differences and insights are found regarding near-source spatial distributions of ground shaking of shallow earthquakes with rupture length greater than about 28 km (Mw > 6.8) with any dip, and for Mw > c. 5.5 with dip < 60º. The influence of asperities relative to that of non-asperities is seen as modest near-fault increases in intensity. The new model can be applied to planar or biplanar fault ruptures of any length, width and dip. In the absence of isoseismal data on large earthquakes with normal focal mechanisms the current model is only verified for use on strike-slip and reverse events. A new concept, seismic-source intensity, is introduced and utilized. The new model can also be applied to earthquakes in other regions of the world with adjustments for local attenuation rates as necessary.

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The evolution of the Kuiper belt during the formation of the outer planets

International Astronomical Union Colloquium ◽

10.1017/s0252921100031213 ◽

1999 ◽

Vol 173 ◽

pp. 37-44

Author(s):

M.D. Melita ◽

A. Brunini

Keyword(s):

Kuiper Belt ◽

Outer Planets ◽

Self Consistent ◽

Planetary Bodies ◽

Mass Depletion

AbstractA self-consistent study of the formation of planetary bodies beyond the orbit of Saturn and the evolution of Kuiper disks is carried out by means of an N-body code where accretion and gravitational encounters are considered. This investigation is focused on the aggregation of massive bodies in the outer planetary region and on the consequences of such process in the corresponding cometary belt. We study the link between the bombardment of massive bodies and mass depletion and eccentricity excitation.

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Gender determination of caucasoid hair using image analysis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100146928 ◽

1993 ◽

Vol 51 ◽

pp. 216-217

Author(s):

T.B. Ball ◽

W.M. Hess

Keyword(s):

Image Analysis ◽

Cross Sections ◽

Scalp Hair ◽

The Body ◽

Equivalent Diameter ◽

Cross Sectional ◽

Hair Samples ◽

Length Width ◽

Morphological Differences

It has been demonstrated that cross sections of bundles of hair can be effectively studied using image analysis. These studies can help to elucidate morphological differences of hair from one region of the body to another. The purpose of the present investigation was to use image analysis to determine whether morphological differences could be demonstrated between male and female human Caucasian terminal scalp hair.Hair samples were taken from the back of the head from 18 caucasoid males and 13 caucasoid females (Figs. 1-2). Bundles of 50 hairs were processed for cross-sectional examination and then analyzed using Prism Image Analysis software on a Macintosh llci computer. Twenty morphological parameters of size and shape were evaluated for each hair cross-section. The size parameters evaluated were area, convex area, perimeter, convex perimeter, length, breadth, fiber length, width, equivalent diameter, and inscribed radius. The shape parameters considered were formfactor, roundness, convexity, solidity, compactness, aspect ratio, elongation, curl, and fractal dimension.

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