<p>The ground-motion duration, the time window in which the ground motion time history is considered to be strong, may be classified into three main groups, i.e., uniform, bracketed, and significant duration. In the current study, the three definitions were employed to argue why "significant duration" is the preferred model to calculate shear wave duration and how it was derived using a modified approach. Using the modified approach, for the first time, the path-dependent part was estimated in Zagros region. The Simulated Annealing inversion method was employed to regress a piecewise-linear function to the medians of path duration versus rupture distance. The data used includes acceleration waveforms obtained from the Iranian strong motion network operated by the Building and Housing Research Center of Iran (BHRC). The events occurred between May 1997 and July 2022 with magnitudes between <InlineEquation ID="IEq1"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10950_2025_10281_Article_IEq1.gif" Format="GIF" Height="16" Rendition="HTML" Resolution="72" Type="Linedraw" Width="29" /> </InlineMediaObject> <EquationSource Format="TEX">${\text{M}}_{\text{W}}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mtext>M</mtext> <mtext>W</mtext> </msub> </math></EquationSource> </InlineEquation> 5.0 and <InlineEquation ID="IEq2"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10950_2025_10281_Article_IEq1.gif" Format="GIF" Height="16" Rendition="HTML" Resolution="72" Type="Linedraw" Width="29" /> </InlineMediaObject> <EquationSource Format="TEX">${\text{M}}_{\text{W}}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mtext>M</mtext> <mtext>W</mtext> </msub> </math></EquationSource> </InlineEquation> 7.3. Using the modified model shows a reduction in duration in the distance range between 100 and 160 km and its effect on ground motion intensity measures (GMIMs). Moreover, the region-specific model predicts a longer duration than those provided by both the traditional model and the model proposed for western North America. Additionally, the contribution of source- and path-dependent duration to the total duration across a wide range of magnitudes and distances was analyzed. The analysis indicated that an accurate estimation of path-dependent duration, even for short distances and large magnitudes, is essential. To demonstrate the reasonableness of the modified model, the EXSIM program (enabling dynamic frequency mode) was employed to simulate peak ground acceleration (PGA) values for earthquakes greater than <InlineEquation ID="IEq3"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10950_2025_10281_Article_IEq1.gif" Format="GIF" Height="16" Rendition="HTML" Resolution="72" Type="Linedraw" Width="29" /> </InlineMediaObject> <EquationSource Format="TEX">${\text{M}}_{\text{W}}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mtext>M</mtext> <mtext>W</mtext> </msub> </math></EquationSource> </InlineEquation> 6.0. Additionally, residual analysis illustrated that the modified model predicted PGA with accuracy and negligible trends. We propose that for other regions with different crustal thicknesses, a new region-specific model must be developed.</p>

Modified path-dependent duration in Zagros, for use in stochastic simulation method

期刊论文
发表日期：

2025年2月4日

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Reza Davoudian,
Hamid Zafarani,
Ahmad Sadidkhouy

摘要

The ground-motion duration, the time window in which the ground motion time history is considered to be strong, may be classified into three main groups, i.e., uniform, bracketed, and significant duration. In the current study, the three definitions were employed to argue why "significant duration" is the preferred model to calculate shear wave duration and how it was derived using a modified approach. Using the modified approach, for the first time, the path-dependent part was estimated in Zagros region. The Simulated Annealing inversion method was employed to regress a piecewise-linear function to the medians of path duration versus rupture distance. The data used includes acceleration waveforms obtained from the Iranian strong motion network operated by the Building and Housing Research Center of Iran (BHRC). The events occurred between May 1997 and July 2022 with magnitudes between ${\text{M}}_{\text{W}}$ $M_{W}$ 5.0 and ${\text{M}}_{\text{W}}$ $M_{W}$ 7.3. Using the modified model shows a reduction in duration in the distance range between 100 and 160 km and its effect on ground motion intensity measures (GMIMs). Moreover, the region-specific model predicts a longer duration than those provided by both the traditional model and the model proposed for western North America. Additionally, the contribution of source- and path-dependent duration to the total duration across a wide range of magnitudes and distances was analyzed. The analysis indicated that an accurate estimation of path-dependent duration, even for short distances and large magnitudes, is essential. To demonstrate the reasonableness of the modified model, the EXSIM program (enabling dynamic frequency mode) was employed to simulate peak ground acceleration (PGA) values for earthquakes greater than ${\text{M}}_{\text{W}}$ $M_{W}$ 6.0. Additionally, residual analysis illustrated that the modified model predicted PGA with accuracy and negligible trends. We propose that for other regions with different crustal thicknesses, a new region-specific model must be developed.