Land movement occurs due to reduced soil strength which is affected by water pressure. The Self Potential (SP) method is a geoelectric method that can detect well the flow of groundwater. The Self Potential method can also be used to detect the presence of debris flow  in the form of weathered soil, tuff sand, cobble gravel and other rock fragments that have mixed with water. Based on the results of the SP measurement, debris flow has a medium SP with a value (3 - 12) mV, rock that has shifted (sandstone associated with andesite fragment) has a SP value <  2mV, while water seepage and water flow has an SP value (13 - 36) mV.

Landslide is a geological event that occurs because the movement of slope-forming material in the form of soil, rock or combination of material type to a lower place due to the influence of gravity. The trigger factor of landslide in Pasanggrahan, South Sumedang, Indonesia is the increase of water content in the slope and the slip plane. The slip plane began to actively to turn on when the rainy season arrives. The infiltration of rainwater into slopes as an avalanche trigger can be detected by Self Potential (SP) method. SP measurements were performed to determine changes in subsurface water flow. SP data acquisition using fixed base technique and leap frog technique. The rocks in the research area that serve as the slip plane are clays associated with Volcanic Breccia. One of the geophysical methods that can identify the slip plane is the Electrical Resistivity Tomography Method. The ERT method can detect slip plane based on rock resistivity. Based on the local geology that has been correlated with the value of Self Potential and Electrical Resistivity Tomography, the following results are obtained: water table : (1 - 13) Ohm.m and SP value : (16 - 50) mV, clay : (72 - 100) Ohm.m and volcanic breccia: (171 - 550) Ohm.m.

Earthquakes with small magnitude and shallow depths are one form of manifestation of existence a fault line in Yogyakarta. Accurate hypocenter determination is needed to identify tectonic and fault conditions based on earthquake hypocenter distribution recorded by seismograf. Hypocenter was determined by using two methods Geiger’s Adaptive Damping for early hypocenter and Modified Joint Hypocenter Determination (MJHD) for relocate hypocenter, we used 2 weeks aftershock data after main quake occurred on June 10-14 2006 with total of 625 events earthquake obtained from the results of picking waves. The difference of hyposenter result on the longitude and latitude is about 2 -25 km and depth change around 0.3-5 km with major distribution to the east from the fault. The final result of this relocation shows that the area is more easily releases energy is in the eastern section of the fault consisting of sedimentary rocks.

Analysis of multiscale scattering and poroelastic attenuation in a real sedimentary rock sequenceAbstract. Attenuation is a physical parameter of rock that can reflect the geological conditions beneath the earth's surface. We conducted attenuation tomographic imaging in the "A" geothermal field by using microearthquake (MEQ) data. We applied a method of spectral fitting to invert the t* value. For the attenuation tomographic inversion, we used the initial 3-D velocity model from the previous study in the region. Our study shows that the value of Qp, Qs and Qp/Qs ratio in the geothermal field is an important parameter for interpreting the subsurface structure. The "A" geothermal field in this study lies between several active and dormant volcanoes in West Java Province, Indonesia. This geothermal field already produces electricity of more than 220 MWe. The hydraulic stimulation has been carried out from the end of 2007 until the beginning of 2008. This experiment was carried out in order to get an understanding about the orientation of weak or fractures zones in the subsurface, so that the strategy of future exploration and well targeting could be estimated. We interpreted the joint immaging result of Qp, Qs and Qp/Qs ratio with previous seismic velocities (Vp, Vs and Vp/Vs ratio) tomography result. We can see that the high attenuation value (low Q value) and low velocity anomaly structures may associated to fluid filled rock and also fault segment.

Abstrak: Metode geolistrik dapat diaplikasikan dalam berbagai bidang keilmuan termasuk lingkungan. Pada penelitian ini memanfaatkan perbedaan resistivitas untuk mengetahui aliran lindi di Tempat Pembuangan Akhir (TPA) Babakan Ciparay, dengan melihat hasil citra bawah permukaan dan diperkuat dengan analisis geokimia. Konfigurasi yang digunakan adalah Wenner dengan spasi elektroda minimum adalah 5 meter. Hasil penelitian menunjukan bahwa lindi mengalir menuju ke arah utara dan ke dataran yang lebih rendah. Hal tersebut dapat dilihat dari nilai resistivitas yang berada pada kisaran 0.019 -6.51 Ωm dan 0.9 -7,5 Ωm. Rentang resitivitas tersebut berada di bawah nilai resistivitas untuk air bersih (fresh water) yakni antara 10 -100 Ωm (Loke, 1997). Hasil tersebut diperkuat dengan hasil uji kualitas air yang dilakukan terhadap parameter kadar nitrit, nitrat, Amoniak total, Fe dan COD. Beberapa parameter kimia tersebut menunjukan bahwa untuk air yang berasal dari kawasan permukiman masih dikategosikan air bersih dan layak, akan tetapi beberapa aliran yang menuju ke wilayah tersebut sudah mengalami pencemaran lindi.Kata kunci: Geolistrik, Geokimia, Lindi, TPA, Ciparay. Abstract: Resistivity method is one of applied geopysics on enviromental issues. In this study resistivity variation and anomaly used to determine the leachate flow in the Babakan Ciparay landfill. The imaging of subsurface resistivity distribution and geochemical analysis lead to describe the area contaminated. Wenner configuration was used with the minimum electrode spacing in 5 meters. The results showed that the leachate flows to the northern part of landfill and to the lower terain.It can be seen from the value of resistivity in the range of 0. 019 -6.51 Ωm and 0.9 -7.5 Ωm. The resitivity range is below the resistivity of water (fresh water) which is between 10-100 Ωm (Loke, 1997