TIME-SERIES GROUND SUBSIDENCE IN BALI BEFORE AND DURING THE COVID-19 PANDEMIC MONITORED BY PS-INSAR METHOD

Some researchers have reported subsidence in Bali. However, the main factor and the subsidence mechanism remain unclear due to a lack of data. One possibility is due to groundwater extraction. During the Covid-19 pandemic, the number of visitors to Bali decreased significantly. Using the persistent interferometric synthetic aperture radar (PS-InSAR) and the trend model method, we found a strong relationship between the number of visitors and the subsidence velocity. The subsidence velocity decreased rapidly during the Covid-19 pandemic. It may cause a decrease in groundwater extraction. It may be proven that groundwater extraction is one factor of subsidence in Bali. However, a detailed field investigation, such as groundwater table measurement, is required to validate this new finding.