Temporal Gravity Gradient of South Kalimantan Region

Abstract

South Kalimantan is one of the provinces in Indonesia facing a problem with the conversion use of peatland. This phenomenon may alter the pattern of some component, such as hydrology, where changes of hydrology further affect the gravity field around the area as well. In this research, the changes in gravity field are estimated using the temporal gravity data from GRACE satellite observations. The data used in this research is the temporal monthly data of the ITSG-Grace2016 from 2014 to 2016, which was the chosen time period to give the latest information available for the temporal gravity data in the region. The obtained gravity field is analysis using the topography maps also the land cover map of South Kalimantan. This research concluded that there have been variations in the mean gradient of gravity in South Kalimantan for period of 2014, 2015 and 2016 with values ranging from -2.23×10-13 to $4.19 \ \mathrm{x}\ 10^{14}$ mgal. The peak point during this period of time takes place on April 2015, while the lowest is on January 2014. It has also been approved that the gravity value is affected by the mass of water, meaning that the gravity gradient values can be used to determine the condition of hydrology in peatland area.