Evaluation of Seismometer Wave Gage and Comparative Analysis of Wave Data at Yaquina and Coquille Bays, Oregon.
Final rept. Jun 84-Feb 85,
COASTAL ENGINEERING RESEARCH CENTER VICKSBURG MS
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This report provides a preliminary evaluation of the seismometer wave gage system developed by Oregon State University OSU. The background and theoretical basis for the OSU system is reviewed. An empirical evaluation is obtained by comparing Yaquina Bay seismometer analyses with data from a pressure gage in the same area during 22 February to 5 March 1984. The pressure gage was funded by the US Army Engineer District, Portland. The OSU system appears to be well suited as a sea state indicator for real-time operational purposes. The system has inherent limitations, particularly for estimating wave period. Comparisons with the pressure gage indicate significant wave heights from the seismometer system are relatively reliable. The correlation coefficient is 0.98, and the mean significant heights differ by 8 percent. Suggestions for improving the seismometer system are provided. The OSU method for analyzing seismometer strip chart records is compared wtih Coastal Engineering Research Center CERC method developed for this study. The CERC method appears to have small advantages. Guidelines for interpreting past OSU analyses are provided. A 2-month comparison between the seismometer and a pressure gage near Coquille Bay is also included. This site has the nearest available coastal gage record with longer-term operation. The gage is funded by the Corps of Engineers Field Data Collection Program. Despite the distance between sites the comparison is favorable, particularly during high-energy winter wave conditions. Author