Heliani, Leni Sophia
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GPS Technology Implementation for Sangihe Islands' Movement Monitoring in 2017-2019 Ulinnuha, Hilmiyati; Lestari, Dwi; Heliani, Leni Sophia; Widjajanti, Nurrohmat; Pratama, Cecep; Parseno, Parseno; Nugroho, Krishna Fitranto
Jurnal Geospasial Indonesia Vol 2, No 2 (2019): December
Publisher : Department of Geodetic Engineering, Faculty of Engineering, Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/jgise.51033

Abstract

Sangihe Islands belong to a complex tectonic area at the subduction of the Eurasian plate and the Philippine Sea. Sangihe subduction zones are complex subduction zone, so that there is a need for continuous movement monitoring. Previous research had been carried out to monitor movement of the Sangihe subduction zone, but no monitoring has been done in 2019. Therefore, this study aims to monitor movement of Sangihe subduction zones with the latest observation data.This study aims to obtain velocity of Sangihe Islands plate movement during 2017 to 2019. Observation was performed using 3 monitoring control points for 7 days in 2019. While observation data from 2017 to 2018 were obtained from previous studies. Observations was carried out using GNSS differential method technology. Loosely constrained of weighted parameter was performed in least square adjustment of GNSS data daily processing, while Kalman Filtering algorithm applied for combining multiyear GNSS data to estimate the velocity refer to ITRF 2014 using GAMIT/GLOBK.This study indicates that Sangihe Islands has horizontal movement to the Southeast with velocity vector of 1 to 2.16 cm/year. This results confirm the previous studies in that area.
Analysis of Sangihe Islands Movements derived from Recent GPS Observation Nugroho, Krishna Fitranto; Heliani, Leni Sophia
Jurnal Geospasial Indonesia Vol 2, No 2 (2019): December
Publisher : Department of Geodetic Engineering, Faculty of Engineering, Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/jgise.51146

Abstract

Sangihe Islands is one of the districts located in the border region of the Republic of Indonesia precisely located in North Sulawesi Province which borders with the Philippines. Sangihe subduction zone is a subduction between the Sangihe plate and the Maluku sea plate. (Di Leo, et al., 2012). This situation causes the Sangihe Islands region to be very prone to earthquake and others disasters, so mitigation efforts are needed to minimize casualties and losses in other material forms. One of these efforts is mapping the potential of earthquakes through Geodynamic studies which are represented at the point of deformation control. This study is using four times GNSS observations epoch 2015, 2016, 2017 and 2018 tied to ITRF 2014. The data used for 3D deformation analysis with the multiepoch method to calculate the movement speed of the Sangihe plate and simultaneous tectonic plate strain observation. The results of this study are the coordinates and accuracy values of monitoring point also the plate movement speed and annual tectonic plate strain values. The movement speed of the Sangihe plate is SGH1 point is having horizontal deformation of 9.88 mm / year to the southeast and vertical deformation descend by 58.66 mm/year. SGH3 point is having horizontal deformation of 12.74 mm/year to the southeast and vertical deformation descend by 18.51 mm/year. SGH4 point is having horizontal deformation of 19.04 mm/year to the southeast and vertical deformation descend by 5.27 mm/ year. This research also proves the hypothesis of a change in the volume of the Sangihe Islands tectonic plate based on the values of normal strain parameters and shear strain in the fraction of 10-6 to 10-4 strains.