IDENTIFIKASI ZONA PENGURANGAN AIR TANAH BERDASARKAN MODEL 3D GAYA BERAT MIKRO ANTAR WAKTU

Supriyadi -(1), WGA Kadir(2), Sarkowi -(3), R Herbet(4),


(1) Gedung D7 Lt 2 Kampus Sekaran Semarang 50229
(2) Geofisika Terapan Institut Teknologi Bandung
(3) Teknik Geofisika Universitas Lampung
(4) Geofisika Terapan Institut Teknologi Bandung

Abstract

Penelitian ini dilatar belakangi oleh kenyataan bahwa di kota Semarang telah terjadi penurunan muka air tanah di beberapa lokasi. Penelitian menggunakan metoda gaya berat mikro antar waktu (time lapse selama kurun waktu Desember 2003 hingga Juni 2004 di daerah Semarang. Tujuan penelitian adalah untuk mengaplikasikan metoda gaya berat mikro dalam menentukan zona pengurangan air tanah dataran aluvial Semarang dan melakukan pemodelan 3D menggunakan program Grav3D untuk identifikasi zona pengur angan air tanah dataran aluvial Semarang. Akusisi metoda gaya berat dilakukan dengan menggunakan alat gravitimeter Lacoste & Romberg tipe G1158 dan G1118 yang dilengkapi dengan alliod 100 untuk mengukur gaya berat tiap stasiun dan gravitimeter Lacoste & Romberg tipe G508 untuk mengukur efek pasang surut terhadap gaya berat. Pemodelan 3D anomali gaya berat mikro time-lapse efek dinamika fluida mampu mengidentifikasi 9 zona pengurangan air tanah yakni sekitar masjid Ataqwa,  PRPP,  Tugu Muda , Simpang Lima,  Jl. Majapahit, Genuk, Tanah Mas, Tanah Putih dan daerah sekitar kelurahan Sendangguwo.

 

The background of this research is that Semarang has experienced the ground water level degradation in some areas. The method used in this research was time lapse microgravity during December 2003 to June 2004. The purpose of the research is to apply the microgravity method in determining the reduction zone of groundwater and alluvial plains Semarang using a 3D modeling by usingGrav3D program to identify the reduction of groundwater zone of alluvial plains in Semarang. The acquisition method of gravity wass done by using a Lacoste & Romberg gravitimeter G1158 and G1118 type equipped with alliod 100 to measure the gravity of each station and Lacoste & Romberg gravitimeter G508 type to measure the tidal effect of the gravity. The 3D modeling microgravity anomaly time-lapse effects of fluid dynamics is able to identify 9 groundwater reduction zones which is about, Ataqwa mosque, PRPP, Tugu Muda, Simpang Lima, Jl. Majapahit, Genuk, Tanah Mas, Tanah Putih, and around Sendangguwo area.

Keywords

time lapse microgravity; groundwater

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