A sinking landscape
In the arid plains of central Myanmar's Magway Region, the ground is slowly sinking. This geological phenomenon, known as subsidence, is a direct consequence of more than a century of intensive oil and gas extraction. The region hosts some of the world's oldest petroleum industries, including the Yenangyaung and Chauk fields, where oil has been extracted since the late 19th century. The first exports of crude oil from British Burma date back to 1853.
The mechanism behind the sinking is a matter of subsurface physics. The oil and gas are trapped in porous sandstone formations deep underground, part of a Cenozoic-era system. The pressure of these hydrocarbons helps support the weight of the overlying rock layers. When oil and gas are pumped to the surface, this underground pressure decreases. Without that support, the porous rock structures compact under the immense weight from above, leading to a gradual drop in the ground level. This process can damage surface infrastructure and alter drainage patterns over large areas. The Central Myanmar Basin contains Cenozoic sediments that can exceed 18 kilometers in thickness, providing a massive column of material to compress.
Measuring the drop from orbit
Detecting such a slow, widespread depression in the land surface is impossible with the naked eye. Scientists use a satellite-based technique called Interferometric Synthetic Aperture Radar (InSAR) to map the changes with millimeter-scale accuracy. Satellites, such as the European Space Agency's Sentinel-1, repeatedly bounce radar signals off the Earth's surface as they orbit. By comparing the radar waves from two different passes over the same area, researchers can create a digital map called an interferogram that reveals tiny shifts in ground elevation.
Studies using InSAR data have confirmed that parts of the Magway oil fields are subsiding at a rate of up to 2 centimeters per year. This deformation is not uniform; it is concentrated in areas directly above the parts of the oil reservoirs experiencing the largest pressure drops from extraction. This data provides a clear link between hydrocarbon production and surface-level changes. While subsidence from oil extraction has been observed in fields globally, monitoring it in historically significant and continuously operated areas like Chauk and Yenangyaung provides a long-term case study of the geological impacts of resource extraction.