David C. Wilson
Emily Wolin
Tyler Storm
L. D. Sandoval
Adam T. Ringler
2020
<p><span>World‐Wide Standardized Seismograph Network (WWSSN) records contain daily calibration pulses that can be used to retrieve the magnification as well as the response of the instrument for a given day record. We analyze a select number of long‐period vertical (LPZ) records from WWSSN station ALQ (Albuquerque, New Mexico). Although we find that the response of this instrument varies widely throughout time, we show that in most cases, we are able to estimate a pole‐zero response that has a root mean square error of </span><span class="inline-formula no-formula-id"><span id="MathJax-Element-1-Frame" class="MathJax" data-mathml="<math xmlns="http://www.w3.org/1998/Math/MathML"><mo xmlns="" form="prefix">&lt;</mo><mn xmlns="">10</mn><mo xmlns="">%</mo></math>"><span id="_mce_caret" data-mce-bogus="1" data-mce-type="format-caret"><span id="MathJax-Span-1" class="math"><span><span id="MathJax-Span-2" class="mrow"><span id="MathJax-Span-3" class="mo"></span></span></span></span></span><span class="MJX_Assistive_MathML"><10%</span></span></span><span>. The variability of responses in historical networks has been reported elsewhere because a large number of adjustments of the galvanometer and seismometer were necessary. Using our derived responses, we estimate noise levels for a number of 1 hr digitized traces. We find that noise levels for the LPZ ALQ records are lower than previously reported, suggesting that these records can resolve smaller amplitude signals than previously suggested. We also find that although care must be taken in the digitization and calibration analysis, we are not limited by noise introduced in the digitization process. Finally, we see that to retrieve the full secondary microseism amplitude, we must use both the LPZ and short‐period components because the LPZ component is limited by system noise at periods less than </span><span class="inline-formula no-formula-id"><span id="MathJax-Element-2-Frame" class="MathJax" data-mathml="<math xmlns="http://www.w3.org/1998/Math/MathML"><mo xmlns="" form="prefix">&#x223C;</mo><mn xmlns="">5</mn><mtext xmlns="">&#x2009;&#x2009;</mtext><mi xmlns="" mathvariant="normal">s</mi></math>"><span class="MJX_Assistive_MathML">∼5 s</span></span></span><span>.</span></p>
application/pdf
10.1785/0220190201
en
Seismological Society of America
Calibration analysis and noise estimates of WWSSN Station ALQ (Albuquerque, New Mexico)
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