Analysis of Time Lapse Microgravity Anomaly Data Case Study in Kota Lama Tourism Area Semarang Indonesia

Abstract

Time lapse microgravity survey has been carried out in Kota Lama Semarang using the Gravimeter Scintrex CG5 on January 2019 and July 2019 with a total of 75 points spread evenly at research field. There are three possible values of gravity anomaly between time, positive, negative, and zero does not change. The results which is an anomaly which is known as time lapse microgravity anomaly show that maximum positive 0,29 mGal in the north and south, and minimum negative -0,11 mGal in northeast and southwest. For the time lapse microgravity vertical gradient anomaly show that maximum positive 0,0013 mGal in west, center, east, and minimum negative -0,0082 mGal in north and south. Conclusion are rainfall data throughout the study range show a downward trend and calculation of groundwater reduction using this data obtained a groundwater level decrease an average of - 3.63 mm.