The area of Los Angeles highlighted in the satellite image below, also referred as the area of interest (AOI), is being monitored for potential ground deformation using RADARSAT-2 satellite radar technology. The AOI covers the Playa del Rey Gas Storage Field as well as the outlying area.
The RADARSAT-2 satellite passes over the AOI every 24 days at an elevation of approximately 500 miles, and covers the AOI in approximately one second while collecting several million readings. The acquired RADARSAT-2 imagery is being used for the generation of deformation maps of the AOI, two of which are delivered to SoCalGas every 6 months. The vertical accuracy of each deformation map is estimated to be in the order of 0.02 feet. This means that systematic deformation over areas larger than approximately a football field are being monitored, detected, and measured. Over time, it is expected that the accumulated deformation data will show in great detail any potential subsidence or uplift in the area. The AOI will be monitored using satellite radar technology for the coming years. Deformation data will be visualized and presented on a regular basis.
The current deformation data produced for the time period December 24, 2009 to June 10, 2010 (see Figure 1) are shown in the figure below (contour intervals of 0.01 ft). In this time period the subtle deformation seen in the Playa del Rey Gas Storage Field is due to seasonal moisture change. During the time period from December 2009 to March 2010 rainfall accumulation contributed to the natural terrain expansion, hence uplift. Subsequently, minimal rainfall occurred from period March 2010 to June 2010 resulting in a decrease in the natural terrain moisture. The next 3 years should confirm what the nature of the changes occurring within the SoCalGas AOI are related to.
The deformation data demonstrate the precision and sensitivity of satellite Synthetic Aperture Radar ("SAR") technology in the AOI between Windsor Hills and Ladera Heights (see Figure 2) where systematic subsidence signals can be observed with a magnitude of approximately 0.03 - 0.05 ft for the referenced time span. West of this is an area of uplift in the order of 0.04 - 0.09 ft.
AOI Satellite Images: Click on images to enlarge
This information is provided solely for informational purposes. Although The Gas Company has used reasonable efforts to assure its accuracy, no representation is made that the contents are free from error or suitable for use for any particular purpose. The Gas Company assumes no responsibility for use of, or reliance on, this information by any party, and specifically advises such parties to discuss any decisions.
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Updated 12/2010