Energy- and Predominant-Period-Dependent P-Wave Onset Picker (EDP-Picker)

2020 ◽  
Vol 91 (4) ◽  
pp. 2355-2367
Author(s):  
Jianqi Lu ◽  
Shanyou Li ◽  
Peiyang He ◽  
Zhinan Xie ◽  
Yan Zhao ◽  
...  
Keyword(s):  
Ambient Noise ◽  
Epicentral Distance ◽  
Strong Motion ◽  
Information Criterion ◽  
Energy Difference ◽  
High Amplitude ◽  
Period Change ◽  
P Wave ◽  
Predominant Period ◽  
Ground Motion Records

Abstract An energy- and predominant-period-dependent (EDP) P-wave onset automatic picking (EDP-picker) algorithm is proposed to deal with the problem of inaccurate P-wave onset picking in cases in which the P-wave onset is hidden in high-amplitude ambient noise or the energy difference between the seismic P-wave and ambient noise is indistinguishable. The algorithm evaluates the energy change using a characteristic variable ΔE, which describes the energy increment of the P wave above ambient noise. The period change is evaluated using two variables with respect to the predominant period, namely Tpd as proposed by Hildyard et al. (2008) and ΔTpd as the gradient of Tpd. The EDP-picker algorithm has two steps: (1) threshold-based cursory P-wave onset picking and (2) precise P-wave onset picking using an Akaike information criterion function, in which both energy information and period information are considered. All three parameters are determined in a 1 s sliding window. The proposed algorithm is verified on a large dataset comprising 13,481 vertical strong ground motion records for 570 events selected from K-NET (Japan) and China Strong Motion Networks Center data. For all records with an epicentral distance of less than 150 km, 93.5% of residuals of manual picks and auto picks are within ±0.5  s. The results demonstrate that EDP-picker is robust and suitable for real-time systems.

An Improved Magnitude Estimation Method Using Combination of Predominant Period and Peak Amplitude for Earthquake Early Warning

2012 ◽  
Vol 256-259 ◽  
pp. 2775-2780
Author(s):  
Jin Dong Song ◽  
Shan You Li
Keyword(s):  
Magnitude Estimation ◽  
Early Warning ◽  
Estimation Method ◽  
Strong Motion ◽  
Earthquake Early Warning ◽  
P Wave ◽  
Peak Amplitude ◽  
Combined Method ◽  
Predominant Period ◽  
Great Magnitude

The critical technology of Earthquake Early Warning (EEW) is determining the size of an earthquake and the predicted ground motion at given site, from the first few seconds of the P wave arrivals. Currently, there were two different approaches to the EEW magnitude estimation, the predominant period method and the peak amplitude method. However, both methods mentioned above had some disadvantages, such as significant uncertainty and saturation at great magnitude. To improve the results of magnitude estimation, a combined method using predominant period τc and peak amplitude of acceleration Pmax was introduced. Compared with the predominant period method and the peak amplitude method, the estimation standard deviation level of the combined method is 0.42 using NSMP strong motion data. The magnitude estimation results of the first three seconds P wave indicate that, the estimation precision of combined method is higher than those of the two methods, the predominant period method and the peak amplitude method, and the saturation at great magnitude is improved.

scholarly journals Seismic Site Classification from the Horizontal-to-Vertical Response Spectral Ratios: Use of the Spanish Strong-Motion Database

Geosciences ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 294 ◽  
Author(s):  
Luis A. Pinzón ◽  
Luis G. Pujades ◽  
Albert Macau ◽  
Emilio Carreño ◽  
Juan M. Alcalde
Keyword(s):  
Epistemic Uncertainty ◽  
Ground Motions ◽  
Strong Motion ◽  
Response Spectra ◽  
Site Classification ◽  
Spectral Ratios ◽  
Predominant Period ◽  
Strong Motion Database ◽  
Ground Motion Records ◽  
Different Response

Normally, the average of the horizontal-to-vertical (H/V) ratios of the 5% damped response spectra of ground motions is used to classify the site of strong-motion stations. In these cases, only the three-orthogonal as-recorded acceleration components are used in the analysis, and all the vector compositions that can generate a different response for each period oscillator are excluded. In this study, the Spanish strong-motion database was used to classify the sites of accelerometric stations based on the predominant periods through the average horizontal-to-vertical spectral ratios (HVSR) of recorded ground motions. Moreover, the directionality effects using the vector composition of the horizontal components of ground motions were also considered in the estimations of H/V ratios. This consideration is a relevant novelty compared to the traditional H/V ratios methods. Only earthquakes with magnitudes above 3.5 and hypocentral distances below 200 km were selected, which resulted in 692 ground-motion records, corresponding to 86 stations, from events in the period between 1993 and 2017. After the analysis, a predominant-period site classification was assigned to each station. On the whole, the obtained mean and standard deviation values of the spectral ratios are comparable to those shown by other researchers. Therefore, the advantages of the proposed procedure, which takes the directionality effects into account, can be summarized as follows: (a) The obtained information is richer and gives enables more sophisticated and realistic analyses on the basis of percentiles and (b) it is easier to detect anomalous stations, sites, and/or accelerograms. Moreover, the method eliminates the effect of directionality as a contributor to epistemic uncertainty.

scholarly journals Simulation of non-stationary stochastic ground motions based on recent Italian earthquakes

2021 ◽  
Author(s):  
Fabio Sabetta ◽  
Antonio Pugliese ◽  
Gabriele Fiorentino ◽  
Giovanni Lanzano ◽  
Lucia Luzi
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Strong Motion ◽  
Stochastic Simulations ◽  
Model Parameters ◽  
Motion Model ◽  
Arias Intensity ◽  
Time Frequency ◽  
Ground Motion Model ◽  
Ground Motion Records

AbstractThis work presents an up-to-date model for the simulation of non-stationary ground motions, including several novelties compared to the original study of Sabetta and Pugliese (Bull Seism Soc Am 86:337–352, 1996). The selection of the input motion in the framework of earthquake engineering has become progressively more important with the growing use of nonlinear dynamic analyses. Regardless of the increasing availability of large strong motion databases, ground motion records are not always available for a given earthquake scenario and site condition, requiring the adoption of simulated time series. Among the different techniques for the generation of ground motion records, we focused on the methods based on stochastic simulations, considering the time- frequency decomposition of the seismic ground motion. We updated the non-stationary stochastic model initially developed in Sabetta and Pugliese (Bull Seism Soc Am 86:337–352, 1996) and later modified by Pousse et al. (Bull Seism Soc Am 96:2103–2117, 2006) and Laurendeau et al. (Nonstationary stochastic simulation of strong ground-motion time histories: application to the Japanese database. 15 WCEE Lisbon, 2012). The model is based on the S-transform that implicitly considers both the amplitude and frequency modulation. The four model parameters required for the simulation are: Arias intensity, significant duration, central frequency, and frequency bandwidth. They were obtained from an empirical ground motion model calibrated using the accelerometric records included in the updated Italian strong-motion database ITACA. The simulated accelerograms show a good match with the ground motion model prediction of several amplitude and frequency measures, such as Arias intensity, peak acceleration, peak velocity, Fourier spectra, and response spectra.

Control of rupture by fault geometry during the 1966 parkfield earthquake

1981 ◽  
Vol 71 (1) ◽  
pp. 95-116 ◽  
Author(s):  
Allan G. Lindh ◽  
David M. Boore
Keyword(s):  
Main Shock ◽  
Fault Plane ◽  
San Andreas Fault ◽  
Strong Motion ◽  
P Wave ◽  
Fault Geometry ◽  
Dynamic Rupture ◽  
San Andreas ◽  
Hill Station ◽  
Parkfield Earthquake

abstract A reanalysis of the available data for the 1966 Parkfield, California, earthquake (ML=512) suggests that although the ground breakage and aftershocks extended about 40 km along the San Andreas Fault, the initial dynamic rupture was only 20 to 25 km in length. The foreshocks and the point of initiation of the main event locate at a small bend in the mapped trace of the fault. Detailed analysis of the P-wave first motions from these events at the Gold Hill station, 20 km southeast, indicates that the bend in the fault extends to depth and apparently represents a physical discontinuity on the fault plane. Other evidence suggests that this discontinuity plays an important part in the recurrence of similar magnitude 5 to 6 earthquakes at Parkfield. Analysis of the strong-motion records suggests that the rupture stopped at another discontinuity in the fault plane, an en-echelon offset near Gold Hill that lies at the boundary on the San Andreas Fault between the zone of aseismic slip and the locked zone on which the great 1857 earthquake occurred. Foreshocks to the 1857 earthquake occurred in this area (Sieh, 1978), and the epicenter of the main shock may have coincided with the offset zone. If it did, a detailed study of the geological and geophysical character of the region might be rewarding in terms of understanding how and why great earthquakes initiate where they do.

The June 13, 1975 earthquake and its relationship to the New Madrid seismic zone

1977 ◽  
Vol 67 (1) ◽  
pp. 209-218
Author(s):  
R. B. Herrmann ◽  
G. W. Fischer ◽  
J. E. Zollweg
Keyword(s):  
Parameter Estimation ◽  
Seismic Moment ◽  
Strong Motion ◽  
P Wave ◽  
Eastern North America ◽  
New Madrid Seismic Zone ◽  
Seismic Zone ◽  
Long Period ◽  
Consistent Solution ◽  
New Madrid

abstract The June 13, 1975 earthquake in the New Madrid seismic zone produced the first recorded strong-motion accelerograms for an event in the region, as well as the largest recorded accelerations to date for any event in eastern North America. The peak strong-motion values obtained from an analysis of the accelerograms are the following: amax = 43 cm/sec2, vmax = 1 cm/sec and dmax = 0.05 cm for the longitudinal S88°W component; amax = 31 cm/sec2, vmax = 0.6 cm/sec and dmax = 0.01 cm for the DOWN component; amax = 64 cm/sec2, vmax = 1.6 cm/sec2, and dmax = 0.09 cm for the tangential S02°E component. Source parameter estimation using long-period surface waves, Lg spectra, P-wave first motions and the integrated accelerograms leads to a consistent solution. The seismic moment is estimated to be 4E21 dyne-cm and the corner period 0.6 sec. The corner period-seismic moment pair for this event agrees with the regional scaling of these parameters observed by Street et al. (1975).

Short-period Lg magnitudes: Instrument, attenuation, and source effects

1983 ◽  
Vol 73 (6A) ◽  
pp. 1835-1850
Author(s):  
Robert B. Herrmann ◽  
Andrzej Kijko
Keyword(s):  
United States ◽  
Epicentral Distance ◽  
P Wave ◽  
Magnitude Scale ◽  
Source Effects ◽  
Anelastic Attenuation ◽  
Basic Conclusion ◽  
Short Period ◽  
Central United States ◽  
Definition Of

Abstract The applicaton of the Nutli (1973) definition of the mbLg magnitude to instruments and wave periods other than the short-period WWSSN seismograph is examined. The basic conclusion is that the Nuttli (1973) definition is applicable to a wider range of seismic instruments if the log10(A/T) term is replaced by log10A. For consistency and precision, the notation mbLg should be applied only to magnitudes based upon 1.0 Hz observations. The mbLg magnitude definition was constrained to be consistent with teleseismic P-wave mb estimates from four Central United States earthquakes. In general, for measurements made at a frequency f, the notation mLg(f) should be used, where m L g ( f ) = 2.94 + 0.833 log ⁡ 10 ( r / 10 ) + 0.4342 γ r + log ⁡ 10 A , and r is the epicentral distance in kilometers, γ is the coefficient of anelastic attenuation, and A is the reduced ground amplitude in microns. Given its stability when estimated from different instruments, the mLg(f) magnitude is an optimum choice for an easily applied, standard magnitude scale for use in regional seismic studies.

i1-net: The Iran Strong Motion Network

2021 ◽  
Author(s):  
Mohammad Pourmohammad Shahvar ◽  
Esmaeil Farzanegan ◽  
Attiyeh Eshaghi ◽  
Hossein Mirzaei
Keyword(s):  
Earthquake Engineering ◽  
Strong Motion ◽  
Current Status ◽  
Primary Input ◽  
The Road ◽  
Leading Position ◽  
Hazard And Risk ◽  
Ground Motion Records ◽  
Strong Motion Network ◽  
Strong Ground

Abstract Strong ground-motion records are the primary input data in earthquake engineering studies to improve understanding of seismic hazard and risk. As the overseer of the Iran Strong Motion Network (i1-net), the Road, Housing, and Urban Development Research Center occupies the leading position in this field in the country. With more than 1260 active accelerometers and a collection of over 14,129 earthquake recordings since 1973, the Iran Strong Motion Network is the major Iranian source of information for engineering seismology and earthquake engineering. The present article describes the current status and developments of the i1-net in the last 46 yr.

scholarly journals Crustal structure beneath Tierra del Fuego, Argentina, inferred from seismic P-wave receiver functions and ambient noise autocorrelations

2019 ◽  
Vol 751 ◽  
pp. 41-53 ◽  
Author(s):  
Carolina Buffoni ◽  
Martin Schimmel ◽  
Nora Cristina Sabbione ◽  
María Laura Rosa ◽  
Gerardo Connon
Keyword(s):  
Crustal Structure ◽  
Ambient Noise ◽  
Receiver Functions ◽  
Tierra Del Fuego ◽  
P Wave
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