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Methods for Amplitude Calibration and Orientation Discrepancy Measurement: Comparing Co‐Located Sensors of Different Types in the Southern California Seismic Network

Li, Zefeng and Hauksson, Egill and Andrews, Jennifer (2019) Methods for Amplitude Calibration and Orientation Discrepancy Measurement: Comparing Co‐Located Sensors of Different Types in the Southern California Seismic Network. Bulletin of the Seismological Society of America, 109 (4). pp. 1563-1570. ISSN 0037-1106. https://resolver.caltech.edu/CaltechAUTHORS:20190625-084518222

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Abstract

Modern seismic networks commonly equip a station with multiple sensors, to extend the frequency band and the dynamic range of data recorded at the station. In addition, in our recent study we showed that comparison of data from co‐located seismometers and accelerometers is useful for detecting instrument malfunctions and monitoring data quality. In this study, we extend comparison of data from different co‐located sensors to two other applications: (1) amplitude calibration for data from vertical short‐period sensors with strong‐motion sensors as baseline and (2) measurement of orientation discrepancy between strong‐motion and broadband sensors. We perform systematic analyses of data recorded by the California Institute of Technology/U.S. Geological Survey Southern California Seismic Network. In the first application, we compare the amplitude of data from vertical short‐period sensors to that of data from co‐located strong‐motion sensors and measure the amplitude calibration factors for 93 short‐period sensors. Among them, 49 stations are measured at ∼1.0⁠, 42 measured at ∼0.6⁠, as well as two outlying stations: GFF at 0.3 and CHI at 1.3. These values are found to be related to the sensors’ sensitivity values. In the second application, we measure orientation discrepancy between 222 co‐located broadband and strong‐motion sensors. All the vertical orientation differences are found to be within 5°. However, the horizontal orientation differences of 22 stations are greater than 6°, among which four stations have reverse rotation or 180° from the expected orientation. These measurements have been communicated to network operators and fixes are being applied. This study, together with our previously developed data monitoring framework, demonstrates that comparison of different co‐located sensors is a simple and effective tool for a broad range of seismic data assessment and instrument calibration.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1785/0120190019DOIArticle
ORCID:
AuthorORCID
Li, Zefeng0000-0003-4405-8872
Hauksson, Egill0000-0002-6834-5051
Andrews, Jennifer0000-0002-5679-5565
Additional Information:© 2019 Seismological Society of America. Manuscript received 31 January 2019; Published Online 25 June 2019. Data and Resources: The seismic waveforms and the earthquake catalog used in this study are from the California Institute of Technology/U.S. Geological Survey (Caltech/USGS) Southern California Seismic Network (SCSN, doi: 10.7914/SN/CI) stored at the Southern California Earthquake Data Center (doi: 10.7909/C3WD3xH1, available at http://scedc.caltech.edu/, last accessed January 2019). The authors are grateful to Associate Editor Cleat P. Zeiler and two anonymous reviewers for their constructive comments that improved this article. The authors also thank Igor Stubailo, Paul Hegarty, Ellen Yu, and Alberto Devora for help in finding the causes of the anomalous amplitude and orientation measurements. This research is supported by a Gordon and Betty Moore Foundation grant to California Institute of Technology (Caltech) and U.S. Geological Survey (USGS) Cooperative Agreements G15AC00023 and G17AC00347.
Group:Seismological Laboratory
Funders:
Funding AgencyGrant Number
Gordon and Betty Moore FoundationUNSPECIFIED
USGSG15AC00023
USGSG17AC00347
Issue or Number:4
Record Number:CaltechAUTHORS:20190625-084518222
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20190625-084518222
Official Citation:Zefeng Li, Egill Hauksson, Jennifer Andrews; Methods for Amplitude Calibration and Orientation Discrepancy Measurement: Comparing Co‐Located Sensors of Different Types in the Southern California Seismic Network. Bulletin of the Seismological Society of America ; 109 (4): 1563–1570. doi: https://doi.org/10.1785/0120190019
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:96683
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:25 Jun 2019 17:42
Last Modified:03 Oct 2019 21:24

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