Geophysics UI students are studying both Geology and Physics in order to understand Geophysics itself, which has some survey methods as tools in exploring the objects. Principles theory of those survey methods has been given in campus as credits, but studying without practicing those methods seems useless. Major of Exploration Geophysics, Department of Physics UI, realize that practicing those survey methods are necessary, so this practice activity comes in 2 different subjects in different times too. First subject given to junior student (3rd year students) and survey did inside campus’ forest (UI) area as introduction. But, the second subject given to senior student (4th year students) and survey will did in the real survey area, in this case: Mount Pancar, Bogor – West Java. This second subject names Geological and Geophysical Survey – Field Camp for 2 credits. Although it is a lecture activity, but UISC AAPG feels honored could supporting this activity.
Geophysical survey methods are consists of: Seismic Methods (Reflection & Refraction), Gravity Method, Geomagnetic Method, Geoelectric & EM Methods (Resistivity, MT, IP, & SP), GPR Method, and Radioactive Method. This activity plans to do 3 geophysical methods, those are: Gravity Method, Geomagnetic Method, and Resistivity Method. Las but not least, we are also planning to do Geological survey, because we could not do any clear interpretation before understanding its geological setting so that we could get the brighter view about what lies below and on the surface. We all know that Seismic Methods are the most familiar survey in Oil and Gas exploration because of its accuracy and depth penetration, but these methods are relatively expensive. This is why Seismic Methods are impossibly taken in preliminary survey. Alternatively, we are using Geological Survey, Gravity Methods, and Geomagnetic Methods in preliminary survey, while Resistivity Methods usually used in special cased i.e. “Basement Fractured”. So, these methods are still necessary and interesting to practice to.
As advance survey in Geophysics UI curriculum, UI Geophysical Lecturers has to choose the right place to survey to, and Mount Pancar is one of the right choices. Mount Pancar is one of place that possibly representatives geothermal system and available to survey on. This hypothesis based on its lithology, which is young Middle – Miocene Andesitic intrusive rocks which possibly could be the mother source. Another consideration is based on the presence of some surface manifestation such as clay alteration, hot pools, and hot spring. The most conspicuous hot springs are Kawah Merah, Kawah Putih, and Kawah Hitam. We will study about this surface manifestation and geological setting by doing simple geological survey without mapping. In order to know what lies below Mount Pancar, we need to do some geophysical survey.
Gravity, Magnetic and resistivity survey design will continue the previous survey design, to complete the data and the conceptual model we made will represent the real geothermal system. Gravity Method is geophysical method which using rocks density as parameter, this survey will held around Mt Pancar, from its slope till summit and gridding survey design in interval ±200-250m. Geomagnetic Method is geophysical method which using rocks susceptibility as parameter, this survey will using the same survey design as Gravity Method did. By doing these methods, we possibly predicted the subsurface layer in Mount Pancar, possibly predicted the mother source, and probably could estimating the reservoir of its geothermal system.
While Resistivity Method is geophysical method which using rocks resistivity as parameter, this survey design will different, because will did in some lines between Kawah Merah, Kawah Hitam and Kawah Putih. By doing this method, hopefully we could determine whether those hot springs are related to Mount Pancar or not and knowing the correlation between those surface manifestations.
After doing those surveys, all participants will process those data acquisition until ready to interpret. Hopefully we could map Mount Pancar subsurface structure and estimate its reservoir location. This activity will be held in 1st – 4th December 2011. As many as 26 students will participate in this activity that will be lead by Mr. Yunus Daud and Mr.Syamsu Rosid as instructor along with his 3 field assistant and under BMKG Operators’ control