A method to establish seismic noise baselines for automated station assessment

Abstract

We present a method for quantifying station noise baselines<SUP> </SUP>and characterizing the spectral shape of out-of-nominal noise<SUP> </SUP>sources. Our intent is to automate this method in order to ensure<SUP> </SUP>that only the highest-quality data are used in rapid earthquake<SUP> </SUP>products at NEIC. In addition, the station noise baselines provide<SUP> </SUP>a valuable tool to support the quality control of GSN and ANSS<SUP> </SUP>backbone data and metadata. The procedures addressed here are currently<SUP> </SUP>in development at the NEIC, and work is underway to understand<SUP> </SUP>how quickly changes from nominal can be observed and used within<SUP> </SUP>the NEIC processing framework. The spectral methods and software<SUP> </SUP>used to compute station baselines and described herein (PQLX)<SUP> </SUP>can be useful to both permanent and portable seismic stations<SUP> </SUP>operators. Applications include: general seismic station and<SUP> </SUP>data quality control (QC), evaluation of instrument responses, assessment<SUP> </SUP>of near real-time communication system performance, characterization<SUP> </SUP>of site cultural noise conditions, and evaluation of sensor vault<SUP> </SUP>design, as well as assessment of gross network capabilities (<U>McNamara </U><U><I>et al.</I></U><U> 2005</U>).<SUP> </SUP>Future PQLX development plans include incorporating station baselines<SUP> </SUP>for automated QC methods and automating station status report generation<SUP> </SUP>and notification based on user-defined QC parameters. The PQLX software<SUP> </SUP>is available through the USGS (<U>) and</U><U><SUP> </SUP></U><U>IRIS (</U><U>).</U>