Published date: Dec 26 2019

Journal Title: KnE Engineering

Issue title: The 1st International Conference on Geodesy, Geomatics, and Land Administration 2019

Pages: 106–114

DOI: 10.18502/keg.v4i3.5834

L M Sabrilmsabri@ft.undip.ac.idDepartment of Geodetic Engineering, Faculty of Engineering, Universitas Diponegoro, Indonesia

Bambang SudarsonoDepartment of Geodetic Engineering, Faculty of Engineering, Universitas Diponegoro, Indonesia

Rina Dwi IndrianaDepartment of Geophysic, Faculty of Science and Mathematic, Universitas Diponegoro, Indonesia

Vertical deflection can be determined by geometrical and physical measurement. In geometrical way, vertical deflection is obtained by comparing astronomical coordinate and geodetical coordinate. In physical way, vertical deflection can be computed from gravity measurement. In the past, vertical deflection was computed from gravity anomaly data. Gravity anomaly data measurement is difficult because it need reduction of gravity from surface of the earth to the geoid using orthometric height from spirit level measurement. In modern era, gravity anomaly data may be replaced by gravity disturbance data whose only required gravity and GNSS (Global Navigation Satellite System) measurement. This research aims to determine vertical deflection in Semarang City from terrestrial gravity disturbance data. The gravity data were measured in March of 2016. Formula of Vening Meinesz that usually used for vertical deflection was replaced by new formula that generated from derivation of function of Hotine. Applying gravity disturbance gave vertical deflection of east-west component that were vary from -1.2” to 12.2” while north-south component were vary from -4.2” to 4.2”. Comparing vertical deflection as computed from terrestrial data to as computed from EGM2008 coefficients showed conformity in shape and values. It was concluded that derivation of function of Hotine could be applied for vertical deflection determination from gravity disturbance.

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