scholarly journals Large Earthquake Magnitude Prediction in Chile with Imbalanced Classifiers and Ensemble Learning

2017 ◽  
Vol 7 (6) ◽  
pp. 625 ◽  
Author(s):  
Manuel Fernández-Gómez ◽  
Gualberto Asencio-Cortés ◽  
Alicia Troncoso ◽  
Francisco Martínez-Álvarez
2019 ◽  
Vol 56 (11) ◽  
pp. 1596-1608
Author(s):  
Priyesh Verma ◽  
Ainur Seidalinova ◽  
Dharma Wijewickreme

In current geotechnical seismic design practice, the empirical correlation between equivalent number of uniform cycles (Neq) of shaking and earthquake magnitude (Mw) forms an integral part of liquefaction potential evaluation. This relationship, in turn, is used to derive the magnitude scaling factors that are commonly used in field-based liquefaction evaluation procedures. The Neq versus Mw relationship for liquefaction assessment was examined for fine-grained soils using time-histories in the range 5 < Mw ≤ 9, especially including strong ground motion time-histories from the latest subduction zone earthquakes with Mw > 8.0. The experimental database available from cyclic direct simple shear tests conducted on natural fine-grained soils retrieved from undisturbed soil sampling was used to obtain the cyclic shear resistance weighting curves for the study. The work presented herein has contributed to further improving the current models used to represent magnitude scaling factor (MSF) values for large earthquake magnitudes and the functional dependency of this parameter on soil type. The MSF–Mw curve derived for low-plastic Fraser River Delta silt lies in-between the MSF curves derived for clean sand and clay, resonating with the inferences that have been made that the silt behavior can neither be considered sand-like nor clay-like.


2020 ◽  
Vol 92 (1) ◽  
pp. 227-237
Author(s):  
Rongxin Fang ◽  
Jiawei Zheng ◽  
Jianghui Geng ◽  
Yuanming Shu ◽  
Chuang Shi ◽  
...  

Abstract Rapid response to destructive tsunami and seismic events requires rapid determination of the earthquake magnitude. We propose a new method that employs peak ground velocities (PGVs) derived from Global Navigation Satellite System (GNSS) data to estimate earthquake magnitudes. With a total of 1434 records from 22 events as the constraints, we perform the regression and obtain a PGV scaling law for magnitude determination. The advantage of the new method is that the PGVs are extracted from the GNSS velocity waveforms, which can be easily computed using broadcast GNSS ephemeris. In contrast, the peak ground displacement (PGD) depends on a sophisticated high-precision GNSS-processing subject to external correction data, realization of which cannot be kept robust constantly, especially in real time. The results show that the PGV magnitudes agree with reported moment magnitudes with mean absolute deviation of 0.26 magnitude units for the 22 events and also agree well with the PGD magnitude. We further demonstrate that GNSS-derived PGV and the modified Mercalli intensity values can be consistent with their counterparts from the U.S. Geological Survey ShakeMap products and therefore the GNSS-derived PGVs have the potential to be included in the ShakeMap as a complementary constraint, especially in areas with sparse seismic station coverage for large earthquake.


1984 ◽  
Vol 1 (1) ◽  
pp. 7-32 ◽  
Author(s):  
Virgilio Perez ◽  
A. Gerald Brady

The study of all earthquake-induced oscillator response peaks from selected records shows how these peaks decrease in amplitude with the number of cycles attaining them. These studies concentrate on the ratio between the peak amplitudes of response experienced throughout the duration of a given number of cycles and the maximum response. The ratio shows a trend that is fairly independent of the structure's period, the epicentral distance, and the earthquake magnitude. If during a very large earthquake a structure is forced into displacements beyond the elastic limit it must withstand them successfully with well-designed ductility. For long-period structures, these inelastic displacements, if assumed to result from idealized elasto-plastic behavior, are approximately equal to the elastic displacements under study. The trends shown here consequently indicate that the amplitudes of the elasto-plastic displacements still attained after two, four, or eight cycles, remain at levels that are appreciably high percentages of the maximum displacement.


2018 ◽  
Vol 28 (2) ◽  
pp. 149-160 ◽  
Author(s):  
Jipan Huang ◽  
Xin'an Wang ◽  
Yong Zhao ◽  
Chen Xin ◽  
Han Xiang

2015 ◽  
Vol 28 (5) ◽  
pp. 1043-1055 ◽  
Author(s):  
G. Asencio-Cortés ◽  
F. Martínez-Álvarez ◽  
A. Troncoso ◽  
A. Morales-Esteban

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