Calibration analysis and noise estimates of WWSSN Station ALQ (Albuquerque, New Mexico)

Seismological Research Letters
By: , and 

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Abstract

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 <10%. 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 ∼5  s.

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Publication type Article
Publication Subtype Journal Article
Title Calibration analysis and noise estimates of WWSSN Station ALQ (Albuquerque, New Mexico)
Series title Seismological Research Letters
DOI 10.1785/0220190201
Volume 91
Issue 3
Year Published 2020
Language English
Publisher Seismological Society of America
Contributing office(s) Geologic Hazards Science Center
Description 8 p.
First page 1359
Last page 1366
Country United States
State New Mexico
City Albuquerque
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