Jakarta, CNBC Indonesia - The National Research and Innovation Agency (BRIN) revealed that, without realizing it, the land could experience subsidence of up to 10 cm per year. Land subsidence occurs slowly. According to BRIN, some areas have seen a decline of more than one meter in 8 years.
However, the cause was not an earthquake or landslide which was immediately felt. However, excessive extraction of groundwater, soft soils, natural compaction of sediments and loading of buildings on soft soils.
This land subsidence also poses a serious threat. The consequences include damage to buildings, road collapses and more frequent thefts.
"Land subsidence poses a serious threat, especially in the northern coast of Java, such as Jakarta, Pekalongan and Sayung, Demak," said Joko Widodo, a researcher at the BRIN Geoinformatics Research Center, in an article published on the official social media account of BRIN, quoted on Friday (10/10/2025).
"If this problem is not addressed through appropriate mitigation and adaptation measures, the impact could be very detrimental, ranging from loss of land area to disruption of life in coastal communities," he added.
It has been explained that land subsidence is a gradual lowering of the earth's surface due to the shrinkage of materials beneath the ground.
The main causes are excessive withdrawal of groundwater, natural compaction of sediments and the weight of buildings on soft ground.
So how can BRIN know that the land has suffered subsidence?
It turns out that BRIN uses PS-InSAR (Persistent Scatterer Interferometric Synthetic Aperture Radar) technology to obtain satellite radar data that detects ground movements with millimeter precision per year.
BRIN monitoring results show that the land situation in Jakarta is quite worrying.
"In the North Jakarta area, the land surface has decreased by approximately 5 to 6 cm per year," BRIN writes.
"In Muara Baru, at high tide, the land is already 2.4 meters below sea level," BRIN continued.
However, BRIN said, not only Jakarta, other cities have also experienced extreme land subsidence.
"Pekalongan experiences land subsidence of 10 to 19 cm per year, one of the highest in Pantura," BRIN wrote.
"BRIN analyzed 45 radar images from 2014 to 2022. Up to 60.9% of the city's area showed a significant decline. Some points even fell by one meter in 8 years," BRIN explained.
BRIN calls this land subsidence a "silent killer", aka the Silent Killer.
"Land subsidence is happening quietly, but the impacts are significant, such as cracking and damage to buildings, seawater penetrating further inland, and flooding ten times faster than sea level rise due to climate," BRIN explained.
He added that there is already a policy on this. But unfortunately, the goal has not yet been achieved.
"DKI Jakarta has Governor's Regulation No. 93/2021 regarding the prohibition of groundwater extraction. But the PS-InSAR analysis results show that the areas with the worst land subsidence, North Jakarta and West Jakarta, are not yet in the prohibited zone," BRIN said.
BRIN also recommends that routine monitoring be carried out using InSAR technology. Apart from this, groundwater extraction. At the same time, public awareness is necessary.
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