scholarly journals Comparison of the Dynamic and Static Corner Frequencies in Ground Motion Simulation: Cases Study of Jiuzhaigou Earthquake and Northridge Earthquake

2022 ◽  
Vol 9 ◽  
Author(s):  
Pengfei Dang ◽  
Qifang Liu ◽  
Linjian Ji
Keyword(s):  
Response Spectra ◽  
Corner Frequency ◽  
Northridge Earthquake ◽  
Acceleration Response ◽  
Jiuzhaigou Earthquake ◽  
Frequency Model ◽  
Ground Motion Simulation ◽  
Finite Fault ◽  
Finite Fault Method ◽  
Dynamic Corner Frequency

By using the stochastic finite-fault method based on static corner frequency (Model 1) and dynamic corner frequency (Model 2), we calculate the far-field received energy (FRE) and acceleration response spectra (SA) and then compare it with the observed SA. The results show that FRE obtained by the two models depends on the subfault size regardless of high-frequency scaling factor (HSF). Considering the HSF, the results obtained by Model 1 and Model 2 are found to be consistent. Then, similar conclusion was obtained from the Northridge earthquake. Finally, we analyzed the reasons and proposed the areas that need to be improved.

Estimation of Damping Correction Factors Using Duration Defined by the Standard Deviation of Phase Difference

2015 ◽  
Vol 31 (2) ◽  
pp. 761-783 ◽  
Author(s):  
Kenichi Nagao ◽  
Jun Kanda
Keyword(s):  
Standard Deviation ◽  
Phase Difference ◽  
Low Frequency ◽  
Response Spectra ◽  
Correction Factors ◽  
Acceleration Response ◽  
Ground Motion Simulation ◽  
Frequency Bands ◽  
Different Types ◽  
Opposite Tendency

The damping correction factors (DCFs) to convert the 5% damping acceleration response spectra to those for other damping levels are computed for the records of 13 Japanese earthquakes. Their correlation with the standard deviation of phase difference ( σ) is also investigated in ten frequency bands. The σ-DCF relations obtained are found to be very similar across the different types of earthquakes. Further, regression analysis suggests that for damping ratios of 1% and 2%, with the increase in σ, the DCFs increase in low-frequency bands (up to 4–5 Hz), whereas they decrease in higher frequency bands. On the other hand, for damping ratios of more than 5%, with the increase in σ, the DCFs decrease in low-frequency bands (up to 1 Hz), whereas the opposite tendency is observed in higher frequency ranges. This research also discusses the applicability of the σ-DCF relations to design ground motion simulation.

Ground-Motion Simulation for the 2008 Wenchuan, China, Earthquake Using the Stochastic Finite-Fault Method

2010 ◽  
Vol 100 (5B) ◽  
pp. 2476-2490 ◽  
Author(s):  
H. Ghasemi ◽  
Y. Fukushima ◽  
K. Koketsu ◽  
H. Miyake ◽  
Z. Wang ◽  
...  
Keyword(s):  
Ground Motion ◽  
Motion Simulation ◽  
Ground Motion Simulation ◽  
Finite Fault ◽  
China Earthquake ◽  
Finite Fault Method

Prediction of Broadband Ground-Motion Time Histories: The Case of Tehran, Iran

2013 ◽  
Vol 29 (2) ◽  
pp. 633-660 ◽  
Author(s):  
Hamid Zafarani ◽  
Hesam Vahidifard ◽  
Anooshirvan Ansari
Keyword(s):  
Ground Motion ◽  
Strong Motion ◽  
Historical Earthquakes ◽  
Response Spectra ◽  
Wave Number ◽  
Corner Frequency ◽  
Earthquake Scenarios ◽  
Motion Time ◽  
Finite Fault ◽  
Time Histories

The northern Tehran fault (NTF) is potentially capable of causing large earth-quakes (Mmax ~ 7.2) in a very densely populated area of northern Tehran, Iran. Due to the lack of recorded strong motion data for earthquakes on the fault, a hybrid simulation method is used to calculate broadband (0.1–20 Hz) ground-motion time histories at bedrock level for deterministic earthquake scenarios on the NTF. Low-frequency components of motion (0.1–1.0 Hz) are calculated using a deterministic approach and the discrete wave number-finite element method in a regional one-dimensional (1-D) velocity model. High frequencies (1.0–20.0 Hz) are calculated by the stochastic finite fault method based on dynamic corner frequency. The results were validated by comparing the simulated peak values and response spectra with the empirical ground motion models available for the area and the Modified Mercalli intensity (MMI) observations from historical earthquakes of the region.

10 July 1894 Istanbul Earthquake: Comparing Damages and Ground Motion Simulations

2021 ◽  
Author(s):  
Nesrin Yenihayat ◽  
Eser Çaktı ◽  
Karin Şeşetyan
Keyword(s):  
Ground Motion ◽  
Fault Simulation ◽  
Source Parameters ◽  
Historical Earthquakes ◽  
Corner Frequency ◽  
Simulation Approach ◽  
Ground Motion Simulations ◽  
Finite Fault ◽  
Intensity Map ◽  
Observed Damage

<p>One of the major earthquakes that resulted in intense damages in Istanbul and its neighborhoods took place on 10 July 1894. The 1894 earthquake resulted in 474 losses of life and 482 injuries. Around 21,000 dwellings were damaged, which is a number that corresponds to 1/7 of the total dwellings of the city at that time. Without any doubt, the exact loss of life was higher. Because of the censorship, the exact loss numbers remained unknown. There is still no consensus about its magnitude, epicentral location, and rupture of length. Even though the hardness of studying with historical records due to their uncertainties and discrepancies, researchers should enlighten the source parameters of the historical earthquakes to minimize the effect of future disasters especially for the cities located close to the most active fault lines as Istanbul. The main target of this study is to enlighten possible source properties of the 1894 earthquake with the help of observed damage distribution and stochastic ground motion simulations. In this paper, stochastic based ground motion scenarios will be performed for the 10 July 1894 Istanbul earthquake, using a finite fault simulation approach with a dynamic corner frequency and the results will be compared with our intensity map obtained from observed damage distributions. To do this, in the first step, obtained damage information from various sources has been presented, evaluated, and interpreted. Secondly, we prepared an intensity map associated with the 1894 earthquake based on macro-seismic information, and damage analysis and classification. For generating ground motions with a stochastic finite fault simulation approach, the EXSIM 2012 software has been used. Using EXSIM, several scenarios are modeled with different source, path, and site parameters. Initial source properties have been obtained from findings of our previous study on the simulation of the 26 September 2019 Silivri (Istanbul) earthquake with Mw 5.8. With the comparison of spatial distributions of the ground motion intensity parameters to the obtained damage and intensity maps, we estimate the optimum location and source parameters of the 1894 Earthquake.</p>

A Numerical Study on the Seismic Site Response of Rocky Valleys with Irregular Topographic Conditions

2019 ◽  
Vol 10 (04) ◽  
pp. 1850011 ◽  
Author(s):  
Mohammad Katebi ◽  
Behrouz Gatmiri ◽  
Pooneh Maghoul
Keyword(s):  
Seismic Analysis ◽  
Numerical Study ◽  
Site Response ◽  
Slope Angle ◽  
Response Spectra ◽  
Topographic Effects ◽  
Combined Effects ◽  
Acceleration Response ◽  
Vertically Propagating ◽  
Maximum Amplification

This paper investigates topographic effects of rocky valleys with irregular topographic conditions subjected to vertically propagating SV waves of Ricker type using a boundary element code. Valleys with two intersecting slopes, [Formula: see text] and [Formula: see text], are modelled in order to study their combined effects on ground motion. Presented in the form of pseudo-acceleration response spectra, results of this work can be extended to similar topographies. The main findings are: (i) [Formula: see text] (the first slope angle) and [Formula: see text] (L is the half width of the valley and [Formula: see text] is its corresponding height) have amplifying effects, and [Formula: see text] (the second slope angle) has de-amplifying effects on the site response. (ii) [Formula: see text] has a straight effect on intensifying the effects of both [Formula: see text] and [Formula: see text]. (iii) The combined effects of slope angles have been found to be important in modifying the response so more than a single slope should be considered for seismic analysis. (iv) Engineers should use the maximum amplification of 2.4 in case of valleys with the first and second slope angles below [Formula: see text].

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