Using 116 earthquakes over M_L3.8 in the Inner Mongolia region from 2008 to 2015, the local earthquake magnitude M_L and surface wave magnitude M_S are remeasured. Based on norm linear regression(SR1 and SR2) and norm...Using 116 earthquakes over M_L3.8 in the Inner Mongolia region from 2008 to 2015, the local earthquake magnitude M_L and surface wave magnitude M_S are remeasured. Based on norm linear regression(SR1 and SR2) and norm(OR) orthogonal regression method, we established the conversion relationship between M_L and M_S. The results were tested with Gaussian disturbance. The result shows that the orthogonal regression method(OR) result has the best fitting curve, and the conversion relation is M_S=0.96 M_L-0.10. The difference between our result and Guo Lücan's(M_S=1.13 M_L-1.08) may be caused by regional tectonic characteristics. M_(S Inner Mongolia) value is significantly higher than the M_(S empirical) value, with an average difference of 0.23, the difference distribution of empirical relation and the rectified relation is in the range of 0.2-0.3.展开更多
By linear regression and orthogonal regression methods, comparisons are made between different magnitudes （local magnitude ML, surface wave magnitudes Ms and MsT, long-period body wave magnitude mB and short-period b...By linear regression and orthogonal regression methods, comparisons are made between different magnitudes （local magnitude ML, surface wave magnitudes Ms and MsT, long-period body wave magnitude mB and short-period body wave magnitude mb） determined by Institute of Geophysics, China Earthquake Administration, on the basis of observation data collected by China Seismograph Network between 1983 and 2004. Empirical relations between different magnitudes have been obtained. The result shows that： ① As different magnitude scales reflect radiated energy by seismic waves within different periods, earthquake magnitudes can be described more objectively by using different scales for earthquakes of different magnitudes. When the epicentral distance is less than 1000 km, local magnitude ME can be a preferable scale; In case M〈4.5, there is little difference between the magnitude scales; In case 4.5〈M〈6.0, mB〉Ms, i.e., Ms underestimates magnitudes of such events, therefore, mB can be a better choice; In case M〉6.0, Ms〉mB〉mb, both mB and mb underestimate the magnitudes, so Ms is a preferable scale for determining magnitudes of such events （6.0〈M〈8.5）; In case M〉8.5, a saturation phenomenon appears in Ms, which cannot give an accurate reflection of the magnitudes of such large events; ② In China, when the epicentral distance is less than 1 000 km, there is almost no difference between ME and Ms, and thus there is no need to convert between the two magnitudes in practice; ③ Although Ms and Ms7 are both surface wave magnitudes, Ms is in general greater than Ms7 by 0.2～0.3 magnitude, because different instruments and calculation formulae are used; ④ mB is almost equal to mb for earthquakes around mB4.0, but mB is larger than mb for those of mB〉4.5, because the periods of seismic waves used for measuring mB and mb are different though the calculation formulae are the same.展开更多
The importance of studying the local magnitude related to seismic activity occurred recently in the region of Itacarambi, state of Minas Gerais, is due to the fact that these were earthquakes of intraplate origin. Fro...The importance of studying the local magnitude related to seismic activity occurred recently in the region of Itacarambi, state of Minas Gerais, is due to the fact that these were earthquakes of intraplate origin. From the study of [1] and the relation between local magnitude and seismic signal duration, was performed a data analysis obtained in the same region, on the period between October/2007 and June/2008, in which we can estimate the equation MD = 2.153 (±0.072) LogD – 1.925 (±0.132) to calculate the magnitude of local duration. We can also estimate one value for the b parameter using the equation LogN = a – bMD from a frequency-magnitude study. It was found the value of b = 0.826 (±0.020) for the general activity of Itacarambi, MG, that is within the universal range proposed by [2].展开更多
In this paper,we give a brief introduction to the proposal and development history of the earthquake magnitude concept. Moment magnitude MWis the best physical quantity for measuring earthquakes. Compared with other m...In this paper,we give a brief introduction to the proposal and development history of the earthquake magnitude concept. Moment magnitude MWis the best physical quantity for measuring earthquakes. Compared with other magnitude scales used traditionally,moment magnitude is not saturated for all earthquakes,regardless of big and small earthquakes,deep and shallow earthquakes,far field and near field seismic data,geodetic and geological data,moment magnitude can be measured,and can be connected with wellknown magnitude scales such as surface wave magnitude MS. Moment magnitude is a uniform magnitude scale,which is suitable for statistics with wide magnitude range.Moment magnitude is the preferred magnitude selected by the International Seismological community,and it is preferred by the departments responsible for publishing seismic information to the public. Moment magnitude is a uniform magnitude scale,which is suitable for statistics with wide magnitude range. Moment magnitude is a preferred magnitude for international seismology,it is preferred by the agency responsible for providing information about earthquakes to the public. We provide all formulas used in the calculation of moment magnitude,and the calculation steps in detail. We also analyzed some problems and rules to solve these problems by using different formulas and numerical value calculation steps.展开更多
In this work a Support Vector Machine Regression（SVMR） algorithm is used to calculate local magnitude（MI） using only five seconds of signal after the P wave onset of one three component seismic station. This algor...In this work a Support Vector Machine Regression（SVMR） algorithm is used to calculate local magnitude（MI） using only five seconds of signal after the P wave onset of one three component seismic station. This algorithm was trained with 863 records of historical earthquakes, where the input regression parameters were an exponential function of the waveform envelope estimated by least squares and the maximum value of the observed waveform for each component in a single station. Ten-fold cross validation was applied for a normalized polynomial kernel obtaining the mean absolute error for different exponents and complexity parameters. The local magnitude（MI） could be estimated with 0.19 units of mean absolute error. The proposed algorithm is easy to implement in hardware and may be used directly after the field seismological sensor to generate fast decisions at seismological control centers, increasing the possibility of having an effective reaction.展开更多
基金sponsored by Science for the Earthquake Resilience,China Earthquake Administration(XH18012)the Major Science and Technology Projects "Application Demonstration Research of Key Engineering Monitoring System Based on Microseismic Location Technology",Inner Mongolia Autonomous Region
文摘Using 116 earthquakes over M_L3.8 in the Inner Mongolia region from 2008 to 2015, the local earthquake magnitude M_L and surface wave magnitude M_S are remeasured. Based on norm linear regression(SR1 and SR2) and norm(OR) orthogonal regression method, we established the conversion relationship between M_L and M_S. The results were tested with Gaussian disturbance. The result shows that the orthogonal regression method(OR) result has the best fitting curve, and the conversion relation is M_S=0.96 M_L-0.10. The difference between our result and Guo Lücan's(M_S=1.13 M_L-1.08) may be caused by regional tectonic characteristics. M_(S Inner Mongolia) value is significantly higher than the M_(S empirical) value, with an average difference of 0.23, the difference distribution of empirical relation and the rectified relation is in the range of 0.2-0.3.
基金Special Project on Earthquake from Ministry of Science and Technology of China.
文摘By linear regression and orthogonal regression methods, comparisons are made between different magnitudes （local magnitude ML, surface wave magnitudes Ms and MsT, long-period body wave magnitude mB and short-period body wave magnitude mb） determined by Institute of Geophysics, China Earthquake Administration, on the basis of observation data collected by China Seismograph Network between 1983 and 2004. Empirical relations between different magnitudes have been obtained. The result shows that： ① As different magnitude scales reflect radiated energy by seismic waves within different periods, earthquake magnitudes can be described more objectively by using different scales for earthquakes of different magnitudes. When the epicentral distance is less than 1000 km, local magnitude ME can be a preferable scale; In case M〈4.5, there is little difference between the magnitude scales; In case 4.5〈M〈6.0, mB〉Ms, i.e., Ms underestimates magnitudes of such events, therefore, mB can be a better choice; In case M〉6.0, Ms〉mB〉mb, both mB and mb underestimate the magnitudes, so Ms is a preferable scale for determining magnitudes of such events （6.0〈M〈8.5）; In case M〉8.5, a saturation phenomenon appears in Ms, which cannot give an accurate reflection of the magnitudes of such large events; ② In China, when the epicentral distance is less than 1 000 km, there is almost no difference between ME and Ms, and thus there is no need to convert between the two magnitudes in practice; ③ Although Ms and Ms7 are both surface wave magnitudes, Ms is in general greater than Ms7 by 0.2～0.3 magnitude, because different instruments and calculation formulae are used; ④ mB is almost equal to mb for earthquakes around mB4.0, but mB is larger than mb for those of mB〉4.5, because the periods of seismic waves used for measuring mB and mb are different though the calculation formulae are the same.
基金CNPq for the funding via PIBICCNPq-3003529/2010-5
文摘The importance of studying the local magnitude related to seismic activity occurred recently in the region of Itacarambi, state of Minas Gerais, is due to the fact that these were earthquakes of intraplate origin. From the study of [1] and the relation between local magnitude and seismic signal duration, was performed a data analysis obtained in the same region, on the period between October/2007 and June/2008, in which we can estimate the equation MD = 2.153 (±0.072) LogD – 1.925 (±0.132) to calculate the magnitude of local duration. We can also estimate one value for the b parameter using the equation LogN = a – bMD from a frequency-magnitude study. It was found the value of b = 0.826 (±0.020) for the general activity of Itacarambi, MG, that is within the universal range proposed by [2].
基金the Monitoring Task of Department of Earthquake Monitoring and Prediction,China Earthquake Administration(2018)Technical Support and Effect Analysis of New Magnitude National Standard Implementation.
文摘In this paper,we give a brief introduction to the proposal and development history of the earthquake magnitude concept. Moment magnitude MWis the best physical quantity for measuring earthquakes. Compared with other magnitude scales used traditionally,moment magnitude is not saturated for all earthquakes,regardless of big and small earthquakes,deep and shallow earthquakes,far field and near field seismic data,geodetic and geological data,moment magnitude can be measured,and can be connected with wellknown magnitude scales such as surface wave magnitude MS. Moment magnitude is a uniform magnitude scale,which is suitable for statistics with wide magnitude range.Moment magnitude is the preferred magnitude selected by the International Seismological community,and it is preferred by the departments responsible for publishing seismic information to the public. Moment magnitude is a uniform magnitude scale,which is suitable for statistics with wide magnitude range. Moment magnitude is a preferred magnitude for international seismology,it is preferred by the agency responsible for providing information about earthquakes to the public. We provide all formulas used in the calculation of moment magnitude,and the calculation steps in detail. We also analyzed some problems and rules to solve these problems by using different formulas and numerical value calculation steps.
文摘In this work a Support Vector Machine Regression（SVMR） algorithm is used to calculate local magnitude（MI） using only five seconds of signal after the P wave onset of one three component seismic station. This algorithm was trained with 863 records of historical earthquakes, where the input regression parameters were an exponential function of the waveform envelope estimated by least squares and the maximum value of the observed waveform for each component in a single station. Ten-fold cross validation was applied for a normalized polynomial kernel obtaining the mean absolute error for different exponents and complexity parameters. The local magnitude（MI） could be estimated with 0.19 units of mean absolute error. The proposed algorithm is easy to implement in hardware and may be used directly after the field seismological sensor to generate fast decisions at seismological control centers, increasing the possibility of having an effective reaction.
