Achmad Yoshi Satriady Muhamad Harfan Yusuf Hadi SELF POTENTIAL (SP)

Self Potential Surveying Introduction This method measures naturally occurring electrical potentials on the ground surface. The spontaneous or natural potentials developed in the earth by electrochemical actions between minerals and subsurface fluids or by electrokinetic processes involving the flow of ionic fluids.

Basic Concept Electrofiltration Potential The flow of fluid through a capillary or porous medium may generate an electrical potential (called the streaming potential) along the flow path

Basic Concept Mineralization Potential

Types of natural electric potential

Types of SP anomalies and their geological source

Field Procedure Fixed-Based Configuration Dipole Configuration (Gradient Configuration)

Aplication of Self-Potential Method Detection of Buried Tank Self-potential signals associated with ground water flow

Lokasi Pengukuran Anomali SP ITB U Lokasi Penelitian Jl.Tamansari Jl.Siliwangi Daerah survey dilakukan di Lebaksiliwangi Sabuga Bandung Luas daerah pengukuran 14 x 9 m2 Teknik pengukuran yang dipakai Metode Amplitudo Potensial

Pola pengukuran Jumlah titik pengukuran 150 grid Jarak tiap titik panjang maupun lebarnya sebesar 1 meter, dengan 1 titik acuan tetap

Kontur Pengukuran Hasil Survey SP

Gambar 3D dari pengukuran SP

Hasil kurva anomali kordinat -4 yang di dapat setelah data processing dari tabel dan grafik disamping diketahui : V(0) = -2,5 mV xo = -0,122 meter L(xi) = hasil pengukuran potensial yang dianggap anomaly q (silinder) = 1 (sesuai referensi menurut Bhatacharya dan Roy) merupakan ordinat posisi yang pada kasus ini posisinya sedikit di geser agar mempermudah perhitungan (dengan menambahkan 4,275)

Hasil kurva anomali kordinat -6 yang di dapat setelah data processing V(0) = -4,3 mV xo = -0,217 meter L(xi) = hasil pengukuran potensial yang dianggap anomaly q (silinder) = 1 (sesuai referensi menurut Bhatacharya dan Roy) merupakan ordinat posisi yang pada kasus ini posisinya sedikit di geser agar mempermudah perhitungan (dengan menambahkan 4,18)

Hasil survey Besar momen dipol yang didapat berupa minus, dalam hal ini dapat di asumsikan bahwa kedua anomali merupakan bahan mineral berbahan konduktor, di prediksi ini merupakan sebuah drum.

Self-potential signals associated with ground water flow (infiltration test from a ditch) Acquisition

Self Potential anomaly expected over water flowing into & out fracture zone Self Potential anomaly expected over water flowing into fracture zone. Self Potential anomaly expected over water flowing into fracture zone.

The Measured Self-Potential Signal (measured along profile 3)

The Self-Potential Signal (perpendicular to the ditch)

References Sharma, Prem V., 2004, Environmental and Engineering Geophysics, Cambridge University Press, UK. A. Boleve et al., A new formulation to compute self-potential signals associated with ground water flow, 2007, Hydrology and earth System Sciences Discussions. Putri, Anggun K., Fenomena Self Potential dan Interpretasinya Dengan Metoda least square, 2006, Universitas Negeri Jakarta, Indonesia.