23
English
eng
Hu, J.
Contributor
<p><span style="margin: 0px; padding: 0px; color: rgb(31, 31, 31); font-family: ElsevierGulliver, Georgia, "Times New Roman", Times, STIXGeneral, "Cambria Math", "Lucida Sans Unicode", "Microsoft Sans Serif", "Segoe UI Symbol", "Arial Unicode MS", serif; font-size: 16px;">In this study, waveform data obtained from Western Sichuan Seismic Array (WSSA) in China was utilized to reveal the temporal variations in coda attenuation around the eastern <a href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/tibet" title="Learn more about Tibet from ScienceDirect's AI-generated Topic Pages" class="topic-link" style="margin: 0px; padding: 0px; background-color: transparent; word-break: break-word; text-decoration-line: underline; text-decoration-thickness: 1px; text-decoration-color: rgb(31, 31, 31); color: rgb(31, 31, 31); text-underline-offset: 1px;">Tibet</a> Plateau and Western Sichuan. Based on the single-scattering model, coda attenuation factor </span><span class="math" style="margin: 0px; padding: 0px; color: rgb(31, 31, 31); font-family: ElsevierGulliver, Georgia, "Times New Roman", Times, STIXGeneral, "Cambria Math", "Lucida Sans Unicode", "Microsoft Sans Serif", "Segoe UI Symbol", "Arial Unicode MS", serif; font-size: 16px;"><span class="MathJax_Preview" style="margin: 0px; padding: 0px; color: rgb(136, 136, 136);"></span><span class="MathJax_SVG" id="MathJax-Element-1-Frame" tabindex="0" data-mathml="<math xmlns="http://www.w3.org/1998/Math/MathML"><mrow is="true"><msubsup is="true"><mi is="true">Q</mi><mi is="true">c</mi><mrow is="true"><mo is="true">−</mo><mn is="true">1</mn></mrow></msubsup></mrow></math>" role="presentation" style="margin: 0px; padding: 0px; display: inline-block; line-height: normal; font-size: 14.4px; word-spacing: normal; overflow-wrap: normal; text-wrap: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; position: relative;"><svg xmlns:xlink="http://www.w3.org/1999/xlink" width="4.171ex" height="2.779ex" viewBox="0 -945.9 1795.9 1196.3" role="img" focusable="false" style="vertical-align: -0.582ex;" aria-hidden="true"><g stroke="currentColor" fill="currentColor" stroke-width="0" transform="matrix(1 0 0 -1 0 0)"><g is="true"><g is="true"><g is="true"><use xlink:href="#MJMATHI-51"></use></g><g is="true" transform="translate(791,403)"><g is="true"><use transform="scale(0.707)" xlink:href="#MJMAIN-2212"></use></g><g is="true" transform="translate(550,0)"><use transform="scale(0.707)" xlink:href="#MJMAIN-31"></use></g></g><g is="true" transform="translate(791,-149)"><use transform="scale(0.707)" xlink:href="#MJMATHI-63"></use></g></g></g></g></svg><span class="MJX_Assistive_MathML" role="presentation" style="margin: 0px; top: 0px; left: 0px; clip: rect(1px, 1px, 1px, 1px); user-select: none; transition: none 0s ease 0s; padding: 1px 0px 0px !important; position: absolute !important; border: 0px !important; height: 1px !important; width: 1px !important; overflow: hidden !important; display: block !important;"><math xmlns="http://www.w3.org/1998/Math/MathML"><mrow is="true"><msubsup is="true"><mi is="true">�</mi><mi is="true">�</mi><mrow is="true"><mo is="true">−</mo><mn is="true">1</mn></mrow></msubsup></mrow></math></span></span></span><span style="color: rgb(31, 31, 31); font-family: ElsevierGulliver, Georgia, "Times New Roman", Times, STIXGeneral, "Cambria Math", "Lucida Sans Unicode", "Microsoft Sans Serif", "Segoe UI Symbol", "Arial Unicode MS", serif; font-size: 16px;"> is calculated in narrower overlapping frequency bands at 1.0–24 Hz by measuring the coda decay rates for local earthquakes before and after the Wenchuan mainshock. The temporal variations in coda attenuation are investigated within three periods. The period I lasted from January 2007 to the end of 2007. The period II lasted from January 2008 till Wenchuan earthquake. The period III lasted from the mainshock to the end of 2008. The resulted temporal variations demonstrate an increase in average </span><span class="math" style="margin: 0px; padding: 0px; color: rgb(31, 31, 31); font-family: ElsevierGulliver, Georgia, "Times New Roman", Times, STIXGeneral, "Cambria Math", "Lucida Sans Unicode", "Microsoft Sans Serif", "Segoe UI Symbol", "Arial Unicode MS", serif; font-size: 16px;"><span class="MathJax_Preview" style="margin: 0px; padding: 0px; color: rgb(136, 136, 136);"></span><span class="MathJax_SVG" id="MathJax-Element-2-Frame" tabindex="0" data-mathml="<math xmlns="http://www.w3.org/1998/Math/MathML"><mrow is="true"><msubsup is="true"><mi is="true">Q</mi><mi is="true">c</mi><mrow is="true"><mo is="true">−</mo><mn is="true">1</mn></mrow></msubsup></mrow></math>" role="presentation" style="margin: 0px; padding: 0px; display: inline-block; line-height: normal; font-size: 14.4px; word-spacing: normal; overflow-wrap: normal; text-wrap: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; position: relative;"><svg xmlns:xlink="http://www.w3.org/1999/xlink" width="4.171ex" height="2.779ex" viewBox="0 -945.9 1795.9 1196.3" role="img" focusable="false" style="vertical-align: -0.582ex;" aria-hidden="true"><g stroke="currentColor" fill="currentColor" stroke-width="0" transform="matrix(1 0 0 -1 0 0)"><g is="true"><g is="true"><g is="true"><use xlink:href="#MJMATHI-51"></use></g><g is="true" transform="translate(791,403)"><g is="true"><use transform="scale(0.707)" xlink:href="#MJMAIN-2212"></use></g><g is="true" transform="translate(550,0)"><use transform="scale(0.707)" xlink:href="#MJMAIN-31"></use></g></g><g is="true" transform="translate(791,-149)"><use transform="scale(0.707)" xlink:href="#MJMATHI-63"></use></g></g></g></g></svg><span class="MJX_Assistive_MathML" role="presentation" style="margin: 0px; top: 0px; left: 0px; clip: rect(1px, 1px, 1px, 1px); user-select: none; transition: none 0s ease 0s; padding: 1px 0px 0px !important; position: absolute !important; border: 0px !important; height: 1px !important; width: 1px !important; overflow: hidden !important; display: block !important;"><math xmlns="http://www.w3.org/1998/Math/MathML"><mrow is="true"><msubsup is="true"><mi is="true">�</mi><mi is="true">�</mi><mrow is="true"><mo is="true">−</mo><mn is="true">1</mn></mrow></msubsup></mrow></math></span></span></span><span style="color: rgb(31, 31, 31); font-family: ElsevierGulliver, Georgia, "Times New Roman", Times, STIXGeneral, "Cambria Math", "Lucida Sans Unicode", "Microsoft Sans Serif", "Segoe UI Symbol", "Arial Unicode MS", serif; font-size: 16px;"> by approximately 35%–45% in the vicinity of Longmenshan and 30%–35% in Sichuan Basin after the Wenchuan earthquake in lower frequency bands within 1.25–8 Hz. On the contrary, the average </span><span class="math" style="margin: 0px; padding: 0px; color: rgb(31, 31, 31); font-family: ElsevierGulliver, Georgia, "Times New Roman", Times, STIXGeneral, "Cambria Math", "Lucida Sans Unicode", "Microsoft Sans Serif", "Segoe UI Symbol", "Arial Unicode MS", serif; font-size: 16px;"><span class="MathJax_Preview" style="margin: 0px; padding: 0px; color: rgb(136, 136, 136);"></span><span class="MathJax_SVG" id="MathJax-Element-3-Frame" tabindex="0" data-mathml="<math xmlns="http://www.w3.org/1998/Math/MathML"><mrow is="true"><msubsup is="true"><mi is="true">Q</mi><mi is="true">c</mi><mrow is="true"><mo is="true">−</mo><mn is="true">1</mn></mrow></msubsup></mrow></math>" role="presentation" style="margin: 0px; padding: 0px; display: inline-block; line-height: normal; font-size: 14.4px; word-spacing: normal; overflow-wrap: normal; text-wrap: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; position: relative;"><svg xmlns:xlink="http://www.w3.org/1999/xlink" width="4.171ex" height="2.779ex" viewBox="0 -945.9 1795.9 1196.3" role="img" focusable="false" style="vertical-align: -0.582ex;" aria-hidden="true"><g stroke="currentColor" fill="currentColor" stroke-width="0" transform="matrix(1 0 0 -1 0 0)"><g is="true"><g is="true"><g is="true"><use xlink:href="#MJMATHI-51"></use></g><g is="true" transform="translate(791,403)"><g is="true"><use transform="scale(0.707)" xlink:href="#MJMAIN-2212"></use></g><g is="true" transform="translate(550,0)"><use transform="scale(0.707)" xlink:href="#MJMAIN-31"></use></g></g><g is="true" transform="translate(791,-149)"><use transform="scale(0.707)" xlink:href="#MJMATHI-63"></use></g></g></g></g></svg><span class="MJX_Assistive_MathML" role="presentation" style="margin: 0px; top: 0px; left: 0px; clip: rect(1px, 1px, 1px, 1px); user-select: none; transition: none 0s ease 0s; padding: 1px 0px 0px !important; position: absolute !important; border: 0px !important; height: 1px !important; width: 1px !important; overflow: hidden !important; display: block !important;"><math xmlns="http://www.w3.org/1998/Math/MathML"><mrow is="true"><msubsup is="true"><mi is="true">�</mi><mi is="true">�</mi><mrow is="true"><mo is="true">−</mo><mn is="true">1</mn></mrow></msubsup></mrow></math></span></span></span><span style="color: rgb(31, 31, 31); font-family: ElsevierGulliver, Georgia, "Times New Roman", Times, STIXGeneral, "Cambria Math", "Lucida Sans Unicode", "Microsoft Sans Serif", "Segoe UI Symbol", "Arial Unicode MS", serif; font-size: 16px;"> is shown to decrease by approximately 10%–18% in southern segment of Longmenshan, 15%–38% in the Chuan-Dian block, and 10–12% in the South China block. These results are confirmed by a statistical </span><em style="margin: 0px; padding: 0px; color: rgb(31, 31, 31); font-family: ElsevierGulliver, Georgia, "Times New Roman", Times, STIXGeneral, "Cambria Math", "Lucida Sans Unicode", "Microsoft Sans Serif", "Segoe UI Symbol", "Arial Unicode MS", serif; font-size: 16px;">t</em><span style="color: rgb(31, 31, 31); font-family: ElsevierGulliver, Georgia, "Times New Roman", Times, STIXGeneral, "Cambria Math", "Lucida Sans Unicode", "Microsoft Sans Serif", "Segoe UI Symbol", "Arial Unicode MS", serif; font-size: 16px;">-test at 99.9% confidence level. No statistically significant change in </span><span class="math" style="margin: 0px; padding: 0px; color: rgb(31, 31, 31); font-family: ElsevierGulliver, Georgia, "Times New Roman", Times, STIXGeneral, "Cambria Math", "Lucida Sans Unicode", "Microsoft Sans Serif", "Segoe UI Symbol", "Arial Unicode MS", serif; font-size: 16px;"><span class="MathJax_Preview" style="margin: 0px; padding: 0px; color: rgb(136, 136, 136);"></span><span class="MathJax_SVG" id="MathJax-Element-4-Frame" tabindex="0" data-mathml="<math xmlns="http://www.w3.org/1998/Math/MathML"><mrow is="true"><msubsup is="true"><mi is="true">Q</mi><mi is="true">c</mi><mrow is="true"><mo is="true">−</mo><mn is="true">1</mn></mrow></msubsup></mrow></math>" role="presentation" style="margin: 0px; padding: 0px; display: inline-block; line-height: normal; font-size: 14.4px; word-spacing: normal; overflow-wrap: normal; text-wrap: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; position: relative;"><svg xmlns:xlink="http://www.w3.org/1999/xlink" width="4.171ex" height="2.779ex" viewBox="0 -945.9 1795.9 1196.3" role="img" focusable="false" style="vertical-align: -0.582ex;" aria-hidden="true"><g stroke="currentColor" fill="currentColor" stroke-width="0" transform="matrix(1 0 0 -1 0 0)"><g is="true"><g is="true"><g is="true"><use xlink:href="#MJMATHI-51"></use></g><g is="true" transform="translate(791,403)"><g is="true"><use transform="scale(0.707)" xlink:href="#MJMAIN-2212"></use></g><g is="true" transform="translate(550,0)"><use transform="scale(0.707)" xlink:href="#MJMAIN-31"></use></g></g><g is="true" transform="translate(791,-149)"><use transform="scale(0.707)" xlink:href="#MJMATHI-63"></use></g></g></g></g></svg><span class="MJX_Assistive_MathML" role="presentation" style="margin: 0px; top: 0px; left: 0px; clip: rect(1px, 1px, 1px, 1px); user-select: none; transition: none 0s ease 0s; padding: 1px 0px 0px !important; position: absolute !important; border: 0px !important; height: 1px !important; width: 1px !important; overflow: hidden !important; display: block !important;"><math xmlns="http://www.w3.org/1998/Math/MathML"><mrow is="true"><msubsup is="true"><mi is="true">�</mi><mi is="true">�</mi><mrow is="true"><mo is="true">−</mo><mn is="true">1</mn></mrow></msubsup></mrow></math></span></span></span><span style="color: rgb(31, 31, 31); font-family: ElsevierGulliver, Georgia, "Times New Roman", Times, STIXGeneral, "Cambria Math", "Lucida Sans Unicode", "Microsoft Sans Serif", "Segoe UI Symbol", "Arial Unicode MS", serif; font-size: 16px;"> (<10%) is found in the Songpan-Ganzi block after the mainshock. Temporal variations of coda attenuation differ significantly in individual blocks after the mainshock. The coda attenuation is proposed to be a beacon to tectonic static stress changes associated with the Wenchuan earthquake.</span><br></p>
Elsevier Ltd.
November 2021
pdf
Geodesy and Geodynamics
Temporal variations in coda attenuation associated with the 2008 Wenchuan (MW7.9) Earthquake in SW, China
mixed material
Elsevier Ltd.