Earthquake Magnitude Scaling Using Peak Ground Velocity Derived from High-Rate GNSS Observations

2020 ◽  
Vol 92 (1) ◽  
pp. 227-237
Author(s):  
Rongxin Fang ◽  
Jiawei Zheng ◽  
Jianghui Geng ◽  
Yuanming Shu ◽  
Chuang Shi ◽  
...  
Keyword(s):  
Rapid Determination ◽  
Seismic Station ◽  
Scaling Law ◽  
Large Earthquake ◽  
Earthquake Magnitude ◽  
New Method ◽  
High Rate ◽  
Peak Ground Velocity ◽  
Absolute Deviation ◽  
Magnitude Scaling

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.

Equivalent number of uniform cycles versus earthquake magnitude relationships for fine-grained soils

2019 ◽  
Vol 56 (11) ◽  
pp. 1596-1608
Author(s):  
Priyesh Verma ◽  
Ainur Seidalinova ◽  
Dharma Wijewickreme
Keyword(s):  
Large Earthquake ◽  
Earthquake Magnitude ◽  
Undisturbed Soil ◽  
Experimental Database ◽  
Cyclic Shear ◽  
Fine Grained ◽  
Evaluation Procedures ◽  
Magnitude Scaling ◽  
Equivalent Number ◽  
Time Histories

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.

scholarly journals The rapid determination of carcass fat by the Foss-Let specific gravity technique

1976 ◽  
Vol 36 (3) ◽  
pp. 567-570 ◽  
Author(s):  
C. J. H. Woodward ◽  
P. Trayhurn ◽  
W. P. T. James
Keyword(s):  
Specific Gravity ◽  
Rapid Determination ◽  
Reference Method ◽  
New Method ◽  
Storage Lipid ◽  
Structural Lipid ◽  
Nutritional Studies

1. Carcass fat was determined by extraction with tetrachloroethylene and measurement of the solvent's change in density. The results were comparable in precision to those of a reference method; the new method extracted storage lipid but little structural lipid.2. The technique is simple, rapid and appropriate for many nutritional studies.

scholarly journals Earthquake Magnitude Estimation from High-Rate GNSS Data: A Case Study of the 2021 Mw 7.3 Maduo Earthquake

2021 ◽  
Vol 13 (21) ◽  
pp. 4478
Author(s):  
Zhiyu Gao ◽  
Yanchuan Li ◽  
Xinjian Shan ◽  
Chuanhua Zhu
Keyword(s):  
Magnitude Estimation ◽  
The United States ◽  
High Rate ◽  
Convergence Time ◽  
Western China ◽  
Peak Ground Velocity ◽  
Stability And Convergence ◽  
Critical Parameters ◽  
United States Geological Survey ◽  
Gnss Data

Peak ground displacement (PGD) and peak ground velocity (PGV) are critical parameters during earthquake early warning, as they can provide rapid magnitude estimation before rupture end. In this study, we used the high-rate Global Navigation Satellite System (GNSS) data from 55 continuous stations to estimate the magnitude of the 2021 Maduo earthquake in western China. We used the relative positioning method and variometric approach to acquire real-time GNSS displacement and velocity waveforms, respectively. The results showed the amplitude of displacement and velocity waveforms gradually decreased with increasing hypocentral distance. Our results showed that the fluctuation of PGD magnitudes over time is smaller than that of PGV magnitudes. Nonetheless, the earthquake magnitudes estimated from both methods were consistent with their counterparts (Mw 7.3) reported by the United States Geological Survey (USGS). The final magnitude estimated from the PGD and PGV methods were Mw 7.25 and Mw 7.31, respectively. In addition, our results highlighted how the number of high-rate GNSS stations could influence the stability and convergence time of magnitude estimation.

Deterministic 3D Ground-Motion Simulations (0–5 Hz) and Surface Topography Effects of the 30 October 2016 Mw 6.5 Norcia, Italy, Earthquake

2021 ◽  
Author(s):  
Arben Pitarka ◽  
Aybige Akinci ◽  
Pasquale De Gori ◽  
Mauro Buttinelli
Keyword(s):  
Surface Topography ◽  
Ground Motion ◽  
Seismic Station ◽  
Ground Motions ◽  
Peak Ground Velocity ◽  
Earth Model ◽  
Rupture Directivity ◽  
Epicentral Area ◽  
Near Fault ◽  
Local Topography

ABSTRACT The Mw 6.5 Norcia, Italy, earthquake occurred on 30 October 2016 and caused extensive damage to buildings in the epicentral area. The earthquake was recorded by a network of strong-motion stations, including 14 stations located within a 5 km distance from the two causative faults. We used a numerical approach for generating seismic waves from two hybrid deterministic and stochastic kinematic fault rupture models propagating through a 3D Earth model derived from seismic tomography and local geology. The broadband simulations were performed in the 0–5 Hz frequency range using a physics-based deterministic approach modeling the earthquake rupture and elastic wave propagation. We used SW4, a finite-difference code that uses a conforming curvilinear mesh, designed to model surface topography with high numerical accuracy. The simulations reproduce the amplitude and duration of observed near-fault ground motions. Our results also suggest that due to the local fault-slip pattern and upward rupture directivity, the spatial pattern of the horizontal near-fault ground motion generated during the earthquake was complex and characterized by several local minima and maxima. Some of these local ground-motion maxima in the near-fault region were not observed because of the sparse station coverage. The simulated peak ground velocity (PGV) is higher than both the recorded PGV and predicted PGV based on empirical models for several areas located above the fault planes. Ground motions calculated with and without surface topography indicate that, on average, the local topography amplifies the ground-motion velocity by 30%. There is correlation between the PGV and local topography, with the PGV being higher at hilltops. In contrast, spatial variations of simulated PGA do not correlate with the surface topography. Simulated ground motions are important for seismic hazard and engineering assessments for areas that lack seismic station coverage and historical recordings from large damaging earthquakes.

scholarly journals A Modified Inverse Distance Weighting Method for Interpolation in Open Public Places Based on Wi-Fi Probe Data

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Da-wei Wang ◽  
Lu-ning Li ◽  
Cheng Hu ◽  
Qiang Li ◽  
Xiang Chen ◽  
...  
Keyword(s):  
Path Selection ◽  
Inverse Distance Weighting ◽  
Location Based Services ◽  
New Method ◽  
Absolute Deviation ◽  
Public Places ◽  
Main Challenge ◽  
Distance Weighting ◽  
Selection Behavior ◽  
Inverse Distance

Urban open places with a public service function (e.g., urban parks) are likely to be populated in peak hours and during public events. To mitigate the risk of overcrowding and even events of stampedes, it is of considerable significance to realize a real-time full coverage estimate of the population density. The main challenge has been the limited deployment of crowd surveillance detectors in open public spaces, leading to incomplete data coverage and thus impacting the quality and reliability of the density estimation. To remedy this issue, this paper proposes a modified inverse distance weighting (IDW) method, named the inverse distance weighting based on path selection behavior (IDWPSB) method. The proposed IDWPSB method adjusts the distance decay effect according to visitors’ path selection behavior, which better characterizes the human dynamics in open spaces. By implementing the model in a real-world road network in the Shichahai scenic area in Beijing, China, the study shows a decrease in the absolute deviation by 17.62% comparing the results between the new method and the traditional IDW method, justifying the effectiveness of the new method for spatial interpolation in open public places. By considering the behavioral factor, the proposed IDWPSB method can provide insights into public safety management with the increasing availability of data derived from location-based services.

scholarly journals Quantitative expression on drought magnitude and disaster intensity

2005 ◽  
Vol 5 (4) ◽  
pp. 495-498 ◽  
Author(s):  
L. H. Feng ◽  
X. C. Zhang
Keyword(s):  
Earthquake Magnitude ◽  
New Method ◽  
Practical Significance ◽  
Quantitative Index ◽  
Quantitative Expression ◽  
Quantitative Calculation ◽  
Disaster Intensity

Abstract. According to the calculation of wind scale and earthquake magnitude, this paper puts forward the concept of drought magnitude and disaster intensity and lays out a new method by quantitative calculation. Drought magnitude is the quantitative index that describes the scale of a drought, and disaster intensity of drought is the quantitative index to describe the loss caused by a drought. Both indices have many theoretical and practical advantages with definable concepts and simple applications; therefore they are of important practical significance.

Rapid determination of source parameters for the 2017 Mw 8.2 Mexico earthquake based on high-rate GPS data

2019 ◽  
Vol 64 (5) ◽  
pp. 1148-1159
Author(s):  
Yunfei Xiang ◽  
Jianping Yue ◽  
Dongjian Cai ◽  
Hao Wang
Keyword(s):  
Rapid Determination ◽  
Source Parameters ◽  
High Rate ◽  
Gps Data ◽  
Mexico Earthquake
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