A new map released recently and obtained with satellite radar data shows us the dangerous subsidence of the San Joaquin Valley, in California (USA).
This map in deceptively tranquil colors was published by NASA’s Earth Observatory. It shows us the subsidence of this California valley over a very short period, between May 2015 and September 2016. This subsidence is notably due to the pumping of groundwater from underground reservoirs. This problem is exacerbated by the recent extreme drought in the Southwestern United States.
According to the Earth Observatory, the california department of resources eau (DWR) recently commissioned NASA’s Jet Propulsion Laboratory (JPL) to monitor this subsidence very closely. This new image was obtained using data from the European Space Agency’s (ESA) Sentinel-1A satellite.
On this map, the areas that are the most yellow represent those that sag the most. According to the JPL report, Corcoran for example (a bowl-shaped depression) subsided about 56 centimeters over this period of just over a year. This area, which extends over about 97 km, was already known for its impressive subsidence, as is the case for another area near El Nido where satellite observations show a subsidence of about 40 cm over the same short period. .
If the problems on these areas were known, satellite observations show a new area of dangerous subsidence near Tranquility where a subsidence of approximately 51 cm has been recorded over an area of 11 km².
The US Geological Survey (USGS) explains that land subsidence can damage buildings, roads, canals and many other infrastructures, not to mention other problems. According to the organization, permanent damage to the underwater aquifer system that holds California’s groundwater is also a problem.