Regression analysis of earthquake magnitude and surface fault length using the 1970 data of Bonilla and Buchanan

Abstract Strain steps have been observed following earthquakes ranging in magnitude from 3.0 to 8.5. An empirical relationship is derived which indicates that the magnitude, M, of the smallest earthquake from which a strain step of the order of 10−9 may be expected at a distance of Δkm is: M = 1.1 + 1.7 log ⁡ Δ 10 . Fault length is related empirically to earthquake magnitude by the equation M = 3.3 + 1.7 log ⁡ L 10 Where L is fault length in km. Comparison of these two equations shows that strains of the order of 10−9 may be expected at distances of approximately 20 fault lengths. The fault length versus magnitude equation presented is shown to be compatible with a previously published energy-magnitude relationship log ⁡ 10 E = A + 1.8 M . Strain steps are shown to have two characteristics which are similar to those of surface waves. The speed of propagation is nearly constant over a wide range of epicentral distances. Depending upon whether the travel paths are continental or oceanic, the speeds are, respectively, 3.0 ± 0.3 km/sec or near 3.6 km/sec. The strain step amplitude dependence upon distance is like R -3/2.

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Stress drop in earthquakes

Bulletin of the Seismological Society of America ◽

10.1785/bssa0580010249 ◽

1968 ◽

Vol 58 (1) ◽

pp. 249-257 ◽

Cited By ~ 4

Author(s):

Chi-Yu King ◽

Leon Knopoff

Keyword(s):

Stress Drop ◽

Earthquake Magnitude ◽

Dislocation Theory ◽

Energy Formula ◽

Fault Trace ◽

Fault Length

abstract A correlation is made between earthquake magnitude and parameters of fault trace on the basis of dislocation theory. For earthquakes with magnitudes M between 5.5 and 8.5, the correlation with fault length L and the maximum horizontal or vertical offset D (both in cm) is approximately log L D 2 = 2.24 M − 4.99. Combining this result with a magnitude-energy formula, it is found that the stress drop is dependent upon magnitude, with the fractional stress drop increasing with magnitude.

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From mapped faults to fault-length earthquake magnitude (FLEM): a test on Italy with methodological implications

Solid Earth ◽

10.5194/se-10-1555-2019 ◽

2019 ◽

Vol 10 (5) ◽

pp. 1555-1579 ◽

Cited By ~ 6

Author(s):

Fabio Trippetta ◽

Patrizio Petricca ◽

Andrea Billi ◽

Cristiano Collettini ◽

Marco Cuffaro ◽

...

Keyword(s):

Stress Field ◽

Strain Rate ◽

Earthquake Magnitude ◽

National Scale ◽

Field Orientation ◽

Scaling Relationships ◽

Fault Length

Abstract. Empirical scaling relationships between fault or slip dimensions and earthquake magnitudes are often used to assess the maximum possible earthquake magnitude of a territory. Upon the assumption of the reactivability of any fault, the earthquake magnitudes derived from the surface fault length (FLEM) are compared at the national scale in Italy against catalogued magnitudes. FLEMs are obtained by considering a comprehensive fault dataset regardless of fault age, stress field orientation, strain rate, etc. In particular, (1) a comprehensive catalogue of all known faults is compiled by merging the most complete databases available; (2) FLEM is then derived from fault length; and (3) the resulting FLEMs are compared (i.e. the mathematical difference) with catalogued earthquake magnitudes. Results show that the largest FLEMs as well as the largest differences between FLEMs and catalogued magnitudes are observed for poorly constrained faults, mainly inferred from subsurface data. It is suggested that these areas have to be further characterized to better estimate fault dimension and segmentation and hence properly assess the FLEM. Where, in contrast, the knowledge of faults is geologically well constrained, the calculated FLEM is often consistent with the catalogued seismicity, with the 2σ value of the distribution of differences being 1.47 and reducing to 0.53 when considering only the Mw≥6.5 earthquakes. Our work highlights areas, in Italy, where further detailed studies on faults are required.

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Impact of Earthquake Magnitude on Lives Lost During Shock

Indonesian Journal of Environmental Management and Sustainability ◽

10.26554/ijems.2021.5.1.21-34 ◽

2021 ◽

Vol 5 (1) ◽

Author(s):

Faruk Ibrahim Gaya ◽

damu Aminu Bara ◽

Ahmad Abdullahi ◽

Mu’azu Audu Zanuwa ◽

Adamu Kamaludeen Muhammad ◽

...

Keyword(s):

Regression Analysis ◽

Data Analysis ◽

Natural Disasters ◽

Natural Environment ◽

Geological Structure ◽

Earthquake Magnitude ◽

History Of ◽

The Impact ◽

The Relationship

Earthquake is one of the catastrophic natural disasters in the history of mankind which consumed hundreds and thousandsof human lives every year. Attitude of man in handling natural environment make earthquakes inevitable. The study wasdesign to examine the impact of earthquake magnitude on lives loss during earthquakes. Data adopted for study are solelysecondary data which include; journals, textbooks, published and unpublished document. Sampled was derived using purposivesampling techniques, earthquakes that lives were loss during their occurrence characterized with 6.0Mw and above wereselected as sample. Regression analysis, maps QGIS software, tables and graphs were used for data analysis in study. Theresult of the research indicate a fair relation among studied variables. Figure 1 Multiple R=0.073, Figure multiple=0.454and Figure multiple R=0.452. Multiple R determine the nature of relation between study variables, the close the value ofmultiple R is to 1 the strong the relationship. Which means fair relationship exist between earthquake magnitudes and liveloss during 1990-2019 earthquakes. And R2 result Figure 1, 1% of the lives lost during earthquakes 1990-1999 are determineby earthquake magnitude, R2 result in Figure 4 indicated 21% of the lives lost during earthquakes 2000-2009 are determineby earthquake magnitude and R2 result in Figure 6 demonstrate 20% of the lives loss during earthquakes 2010-2019 aredetermine by earthquake magnitudes. Significant F results are Figure 1 significant F =0.613, Figure 4 significant F=0.001 andFigure 6 significant F=0.0004. Two out of the three significant F result indicated that the result of the research is reliablewhile one result indicated that the result is less reliable. However, the result of the research signifies, other factors such aspopulation density of the area where the earthquakes occur, the geological structure of the areas where the earthquake takeplace, the time at which the earthquake occur i.e. night or during daylight and precipitation also trigger earthquakes in a fewkilometer depth influence number lives lost during earthquake.

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