The image of Dr. Poland of the United States Geological Survey (USGS) standing next to a marked powerline in 1977 is circulated as a striking example of land subsidence. This and other historical data are common references for modern subsidence studies. Because of the significance of this data, recent work was conducted to analyze the historical data as well as independently measure the magnitude of subsidence since 1975, within the same study area southwest of Mendota, CA. The results indicate that local subsidence in the area of the photo is less than 0.5 meters between 1975 and 2017. Furthermore the results identify inconsistencies that may challenge the historical certainty of some local subsidence data. Procedures and methods used in the survey will also be discussed.


Bioresource and Agricultural Engineering

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This material may be downloaded for personal use only. Any other use requires prior permission of the American Society of Civil Engineers. This material may be found at https://ascelibrary.org/doi/abs/10.1061/9780784481400.005.


URL: https://digitalcommons.calpoly.edu/bae_fac/143