Valerie J. Sahakian
Elias King
Annemarie S. Baltay Sundstrom
Alexis Klimasewski
Tara Nye
2023
<p><span>Ground‐motion studies are a key component of seismic hazard analyses and often rely on information of the source, path, and site. Extensive research has been done on each of these parameters; however, site‐specific studies are of particular interest to seismic hazard studies, especially in the field of earthquake engineering, as near‐site conditions can have a significant impact on the resulting ground motion at a site. There has been much focus on the constraint of site parameters and their application to seismic hazard studies, especially in the development of ground‐motion models (GMMs). Kappa is an observational parameter describing the high‐frequency attenuation of spectra, and its site contribution (</span><span class="inline-formula no-formula-id"><span id="MathJax-Element-3-Frame" class="MathJax" data-mathml="<math xmlns="http://www.w3.org/1998/Math/MathML"><msub xmlns=""><mi>&#x3BA;</mi><mn>0</mn></msub></math>"><span id="MathJax-Span-11" class="math"><span><span id="MathJax-Span-12" class="mrow"><span id="MathJax-Span-13" class="msub"><span id="MathJax-Span-14" class="mi">κ</span><span id="MathJax-Span-15" class="mn">0</span></span></span></span></span></span></span><span>) has shown to be a good predictor of high‐frequency ground motions; however, measurements are often limited. In this study, we develop a <span class="inline-formula no-formula-id"><span id="MathJax-Element-3-Frame" class="MathJax" data-mathml="<math xmlns="http://www.w3.org/1998/Math/MathML"><msub xmlns=""><mi>&#x3BA;</mi><mn>0</mn></msub></math>"><span id="MathJax-Span-11" class="math"><span id="MathJax-Span-12" class="mrow"><span id="MathJax-Span-13" class="msub"><span id="MathJax-Span-14" class="mi">κ</span><span id="MathJax-Span-15" class="mn">0</span></span></span></span></span></span></span><span> dataset for the San Francisco Bay area (SFBA) by estimating </span><span class="inline-formula no-formula-id"><span id="MathJax-Element-5-Frame" class="MathJax" data-mathml="<math xmlns="http://www.w3.org/1998/Math/MathML"><msub xmlns=""><mi>&#x3BA;</mi><mn>0</mn></msub></math>"><span id="MathJax-Span-21" class="math"><span><span id="MathJax-Span-22" class="mrow"><span id="MathJax-Span-23" class="msub"><span id="MathJax-Span-24" class="mi">κ</span></span></span></span></span><span class="MJX_Assistive_MathML">0</span></span></span><span> for 228 stations, and we produce a continuous regional map of </span><span class="inline-formula no-formula-id"><span id="MathJax-Element-6-Frame" class="MathJax" data-mathml="<math xmlns="http://www.w3.org/1998/Math/MathML"><msub xmlns=""><mi>&#x3BA;</mi><mn>0</mn></msub></math>"><span id="MathJax-Span-26" class="math"><span><span id="MathJax-Span-27" class="mrow"><span id="MathJax-Span-28" class="msub"><span id="MathJax-Span-29" class="mi">κ</span></span></span></span></span><span class="MJX_Assistive_MathML">0</span></span></span><span>. We find <span class="inline-formula no-formula-id"><span id="MathJax-Element-3-Frame" class="MathJax" data-mathml="<math xmlns="http://www.w3.org/1998/Math/MathML"><msub xmlns=""><mi>&#x3BA;</mi><mn>0</mn></msub></math>"><span id="MathJax-Span-11" class="math"><span id="MathJax-Span-12" class="mrow"><span id="MathJax-Span-13" class="msub"><span id="MathJax-Span-14" class="mi">κ</span><span id="MathJax-Span-15" class="mn">0</span></span></span></span></span></span></span><span> to range between 0.003 and 0.072 s, with larger values concentrating on the east, north, and south sides of the bay, and lower values concentrating on the west side. We also evaluate the robustness of </span><span class="inline-formula no-formula-id"><span id="MathJax-Element-8-Frame" class="MathJax" data-mathml="<math xmlns="http://www.w3.org/1998/Math/MathML"><msub xmlns=""><mi>&#x3BA;</mi><mn>0</mn></msub></math>"><span id="MathJax-Span-36" class="math"><span><span id="MathJax-Span-37" class="mrow"><span id="MathJax-Span-38" class="msub"><span id="MathJax-Span-39" class="mi">κ</span></span></span></span></span><span class="MJX_Assistive_MathML">0</span></span></span><span> as a site parameter and find it to correlate with peak ground acceleration. These estimates of </span><span class="inline-formula no-formula-id"><span id="MathJax-Element-9-Frame" class="MathJax" data-mathml="<math xmlns="http://www.w3.org/1998/Math/MathML"><msub xmlns=""><mi>&#x3BA;</mi><mn>0</mn></msub></math>"><span id="MathJax-Span-41" class="math"><span><span id="MathJax-Span-42" class="mrow"><span id="MathJax-Span-43" class="msub"><span id="MathJax-Span-44" class="mi">κ</span></span></span></span></span><span class="MJX_Assistive_MathML">0</span></span></span><span> can add predictive power to GMMs, thus increasing the accuracy of predicted ground motion and improving the robustness of ground‐motion studies in the SFBA.</span></p>
application/pdf
10.1785/0120220046
en
Seismological Society of America
Estimates of k0 and effects on ground motions in the San Francisco Bay area
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