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    Statistical evaluation and probabilistic modeling of aftershock sequences of Iranian plateau

    , Article Journal of Seismology ; Volume 22, Issue 5 , 2018 , Pages 1249-1261 ; 13834649 (ISSN) Khansefid, A ; Bakhshi, A ; Sharif University of Technology
    Springer Netherlands  2018
    The present research focuses on the statistical evaluation of Iranian plateau aftershocks from an engineering perspective and presents probabilistic models applicable for generating random earthquake scenarios. Accordingly, a comprehensive earthquake data catalog including the period from 1964 to 2016 is prepared. Data are declustered into 37 separate mainshock-aftershock sequences by considering the completeness moment magnitude of the database. The well-known modified Omori occurrence rate formula is adopted to determine the recurrence time of the events, considering the effect of secondary aftershocks. In addition to computing the probability density functions of the parameters of the... 

    Development of declustered processed earthquake accelerogram database for the Iranian Plateau: including near-field record categorization

    , Article Journal of Seismology ; Volume 23, Issue 4 , 2019 , Pages 869-888 ; 13834649 (ISSN) Khansefid, A ; Bakhshi, A ; Ansari, A ; Sharif University of Technology
    Springer Netherlands  2019
    In this paper, a comprehensive accelerogram database of the Iranian plateau containing 3585 data with all three components is gathered. The raw data are processed by the wavelet-based denoising method, and results are compared with the contaminated data. All the data are classified into mainshock and aftershock categories using the time and spatial window method. Afterward, the data are categorized into the pulse-like and non-pulse-like events based on the detection of velocity pulse in any of horizontal and/or vertical directions. Eventually, among 3585 data, the ones with an average shear wave velocity of top 30 m of subsurface soil profile are selected and their important ground motion... 

    The exact and approximate conditional spectra in the multi-seismic-sources regions

    , Article Soil Dynamics and Earthquake Engineering ; Volume 39 , August , 2012 , Pages 61-77 ; 02677261 (ISSN) Ebrahimian, H ; Azarbakht, A ; Tabandeh, A ; Akbar Golafshani, A ; Sharif University of Technology
    Elsevier  2012
    The exact and two approximate conditional spectra are compared in this manuscript as a target spectrum for the purpose of ground motion selection. The considered site is a real offshore site located at South Pars Gas Field in the Persian Gulf region. This case study site is influenced by four major seismic area sources in which the deaggregation results confirm that many comparable seismic scenarios can be taken into account. Therefore, an alternative to the conventional approximate conditional spectrum is proposed that has a small deviation from the exact solution. In addition, the use of different conditioning status of the probabilistic seismic hazard deaggregation (i.e., occurrence... 

    Estimation of stress drop for some large shallow earthquakes using stochastic point source and finite fault modeling

    , Article Scientia Iranica ; Volume 17, Issue 3 A , JUNE , 2010 , Pages 217-235 ; 10263098 (ISSN) Moghaddam, H ; Fanaie, N ; Motazedian, D ; Sharif University of Technology
    Using stochastic point source and finite fault modeling, the stochastic stress drop is estimated for 52 large shallow earthquakes listed in the 'Pacific Earthquake Engineering Research Center (PEER) Next Generation Attenuation of Ground Motions (NGA)' database. The Pseudo Spectral Acceleration (PSA) of 541 accelerograms, recorded at National Earthquake Hazards Reduction Program (NEHRP) C-class sites from 52 earthquakes are simulated and compared with the PSA listed in the PEER NGA database. The magnitude of the analyzed earthquakes ranged from M4:4 to M7:6. The stress drop is calibrated by trial and error and based on the analysis of residuals where the residual is defined as the log of the... 

    A comparative study of earthquake source models in high-order accurate tsunami simulations

    , Article Ocean Modelling ; Volume 141 , 2019 ; 14635003 (ISSN) Hajihassanpour, M ; Bonev, B ; Hesthaven, J. S ; Sharif University of Technology
    Elsevier Ltd  2019
    The discontinuous Galerkin method is used to solve the non-linear spherical shallow water equations with Coriolis force. The numerical method is well-balanced and takes wetting/drying into account. The two fold goal of this work is a comparative study of dynamic and static tsunami generation by seabed displacement and the careful validation of these source models. The numerical results show that the impact of the choice of seabed displacement model can be significant and that using a static approach may result in inaccurate results. For the validation of the studies, we consider measurements from satellites and buoy networks for the 2011 Tohoku event and the 2004 Sumatra–Andaman tsunami. The...