One large quake last Wednesday, two more smaller quakes on Monday
By CA Department of Water Resources
News of yet another earthquake in the heart of the Delta in the last week is a serious reminder about the importance of modernizing and protecting water supply infrastructure. The quake on Wednesday, Oct. 18th measured 4.2 and was centered 5 kilometers southwest of Isleton. Two more quakes measuring 2.9 magnitude and 2.5 mag, with epicenters 4 km southeast of Rio Vista, occurred on Monday, Oct. 23, according to the US Geological Survey (USGS).
In a report by CBS News last week, Austin Elliott with the USGS said that “a very large earthquake, centered near the Delta, would pose a particularly significant threat to both protective systems that the levees provide, as well as the water distribution and intake systems.”
He also said that “Larger earthquakes magnitude — five or six — would begin to produce liquefaction and damage some of the infrastructure and geotechnical work there.” And according to the USGS, there is a 72 percent chance of a 6.7 or greater magnitude earthquake occurring in the Bay Area by 2043.
The Delta Conveyance Project is meant to help the State Water Project guard against these seismic threats.
DWR has also invested millions of dollars to reinforce many Delta levees through the Delta Levees Special Flood Control Projects programs. Additionally, DWR has been planning for and strategizing how to address the earthquake risk and potential disruption to California’s water supply and has developed detailed plans to guide response and recovery efforts.
For more information on how the proposed Delta Conveyance Project would make California’s water supply more earthquake resilient, check out this digital article and these two in-depth videos (Part 1 and Part 2).
Allen D. Payton contributed to this report.