California is caving in at a rate even faster than earlier thought, satellite images from the National Aeronautics and Space Administration (NASA) revealed recently.

The images from the space agency showed how some parts of California are sinking—a scientific phenomenon called subsidence—at an astonishing rate. The Sacramento Valley, for instance, is sinking about half an inch per month.

Regions of the Tulare Basin, which includes Fresno, meanwhile shrank by 13 inches in just eight months.

The California Aqueduct—which delivers water from the Sierra Nevada mountains in northern and central California to Southern California through an intricate network of pipes, canals and tunnels, for its part—has already sunk by over a foot, most of which occurred during the past months.

What exactly is triggering California's faster shrinking? Officials believe that it is connected with the drought the Golden State is currently experiencing, considered to be the worst one in decades.

Mark Cowin, director of California's Department of Water Resources, explained that the extreme drought has caused intense pumping out of groundwater.

"Because of increased pumping, groundwater levels are reaching record lows — up to 100 feet (30 meters) lower than previous records," Cowin explained.

"As extensive groundwater pumping continues, the land is sinking more rapidly, and this puts nearby infrastructure at greater risk of costly damage," he added.

The high demand for groundwater in certain regions largely comes from agricultural areas. In fact, the state's fast-shrinking regions also account for most of California's agricultural output.

Farmers have mainly resorted to pumping out groundwater because their usual sources of surface water for irrigation, the San Joaquin and Sacramento rivers, are already drying up.

This voracious groundwater pumping, however, can have permanent negative effects. For instance, the land can permanently lose its ability to store groundwater if it sinks too much.

The fast shrinking of land in California can also have dangerous effects in infrastructure. It can cause roads, bridges and flood control structures to crack and cave in.

"Groundwater acts as a savings account to provide supplies during drought, but the NASA report shows the consequences of excessive withdrawals as we head into the fifth year of historic drought," Corwin said.

"We will work together with counties, local water districts, and affected communities to identify ways to slow the rate of subsidence and protect vital infrastructure such as canals, pumping stations, bridges and wells," he added.

The NASA satellite images showing a faster shrinking California were produced through the use of Japan's satellite-based Phased Array type L-band Synthetic Aperture Radar, Canada's Earth Observation satellite Radarsat-2, and NASA's airplane-based Uninhabited Aerial Vehicle Synthetic Aperture Radar.