NASA data show that California's San Joaquin Valley is still subsiding, meaning that the land is slowly and continuously sinking. Although subsidence has gradually slowed since peaking in the mid-20th century, ongoing ground uplift due to tectonic changes along the Pacific Coast, rising sea levels, loss of groundwater and oil reservoirs, among other environmental stressors and natural occurrences, contribute to the region's subsidence problem. As one of the country's most agricultural-rich areas, this land displacement poses various significant socio-economic and land-use challenges to the San Joaquin Valley and California as a whole.